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<h1 align="center">
C-language Interface Specification for SQLite
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<p>This page is intended to be a precise and detailed specification.
For a tutorial introductions, see instead:
<ul>
<li><a href="quickstart.html">SQLite In 3 Minutes Or Less</a> and/or
<li>the <a href="cintro.html">Introduction To The SQLite C/C++ Interface</a>.
</ul>
This same content is also available split out into
<a href="../c3ref/intro.html">some smaller pages</a>.</p>
<hr>
<h2>Experimental And Deprecated Interfaces</h2>
<p>SQLite interfaces can be subdivided into three categories:</p>
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<li>Stable</li>
<li>Experimental</li>
<li>Deprecated</li>
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<p>Experimental interfaces are subject to change.
Applications that use experimental interfaces
may need to be modified when upgrading to a newer SQLite release, though
this is rare.
When new interfaces are added to SQLite, they generally begin
as experimental interfaces. After an interface has been in use for
a while and the developers are confident that the design of the interface
is sound and worthy of long-term support, the interface is marked
as stable.</p>
<p>Deprecated interfaces have been superceded by better methods of
accomplishing the same thing and should be avoided in new applications.
Deprecated interfaces continue to be supported for the sake of
backwards compatibility. At some point in the future, it is possible
that deprecated interfaces may be removed.</p>
<p>Key points:</p>
<ul>
<li>Experimental interfaces are subject to change and/or removal
at any time.</li>
<li>Deprecated interfaces should not be used in new code and might
be removed in some future release.</li>
</ul>
<hr>
<h2>List Of Objects:</h2>
<div class='columns' style='columns: 14em auto;'>
<ul style='padding-top:0;'>
<li><a href='#sqlite3'>sqlite3</a></li>
<li><a href='#sqlite3_api_routines'>sqlite3_api_routines</a></li>
<li><a href='#sqlite3_backup'>sqlite3_backup</a></li>
<li><a href='#sqlite3_blob'>sqlite3_blob</a></li>
<li><a href='#sqlite3_context'>sqlite3_context</a></li>
<li><a href='#sqlite3_data_directory'>sqlite3_data_directory</a></li>
<li><a href='#sqlite3_file'>sqlite3_file</a></li>
<li><a href='#sqlite3_filename'>sqlite3_filename</a></li>
<li><a href='#sqlite3_index_info'>sqlite3_index_info</a></li>
<li><a href='#sqlite3_int64'>sqlite3_int64</a></li>
<li><a href='#sqlite3_int64'>sqlite3_uint64</a></li>
<li><a href='#sqlite3_int64'>sqlite_int64</a></li>
<li><a href='#sqlite3_int64'>sqlite_uint64</a></li>
<li><a href='#sqlite3_io_methods'>sqlite3_io_methods</a></li>
<li><a href='#sqlite3_mem_methods'>sqlite3_mem_methods</a></li>
<li><a href='#sqlite3_module'>sqlite3_module</a></li>
<li><a href='#sqlite3_mutex'>sqlite3_mutex</a></li>
<li><a href='#sqlite3_mutex_methods'>sqlite3_mutex_methods</a></li>
<li><a href='#sqlite3_pcache'>sqlite3_pcache</a></li>
<li><a href='#sqlite3_pcache_methods2'>sqlite3_pcache_methods2</a></li>
<li><a href='#sqlite3_pcache_page'>sqlite3_pcache_page</a></li>
<li><a href='#sqlite3_snapshot'>sqlite3_snapshot</a></li>
<li><a href='#sqlite3_stmt'>sqlite3_stmt</a></li>
<li><a href='#sqlite3_str'>sqlite3_str</a></li>
<li><a href='#sqlite3_temp_directory'>sqlite3_temp_directory</a></li>
<li><a href='#sqlite3_value'>sqlite3_value</a></li>
<li><a href='#sqlite3_vfs'>sqlite3_vfs</a></li>
<li><a href='#sqlite3_vtab'>sqlite3_vtab</a></li>
<li><a href='#sqlite3_vtab_cursor'>sqlite3_vtab_cursor</a></li>
</ul>
</div>
<hr>
<h2>List Of Constants:</h2>
<p>Also available: <a href="rescode.html">list of error codes</a></p>
<div class='columns' style='columns: 20em auto;'>
<ul style='padding-top:0;'>
<li><a href='#SQLITE_ABORT'>SQLITE_ABORT</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_ABORT_ROLLBACK</a></li>
<li><a href='#SQLITE_ACCESS_EXISTS'>SQLITE_ACCESS_EXISTS</a></li>
<li><a href='#SQLITE_ACCESS_EXISTS'>SQLITE_ACCESS_READ</a></li>
<li><a href='#SQLITE_ACCESS_EXISTS'>SQLITE_ACCESS_READWRITE</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_ALTER_TABLE</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_ANALYZE</a></li>
<li><a href='#SQLITE_ANY'>SQLITE_ANY</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_ATTACH</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_AUTH</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_AUTH_USER</a></li>
<li><a href='#SQLITE_BLOB'>SQLITE_BLOB</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_BUSY</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_BUSY_RECOVERY</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_BUSY_SNAPSHOT</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_BUSY_TIMEOUT</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_CANTOPEN</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_CONVPATH</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_DIRTYWAL</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_FULLPATH</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_ISDIR</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_NOTEMPDIR</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_SYMLINK</a></li>
<li><a href='#SQLITE_CHECKPOINT_FULL'>SQLITE_CHECKPOINT_FULL</a></li>
<li><a href='#SQLITE_CHECKPOINT_FULL'>SQLITE_CHECKPOINT_PASSIVE</a></li>
<li><a href='#SQLITE_CHECKPOINT_FULL'>SQLITE_CHECKPOINT_RESTART</a></li>
<li><a href='#SQLITE_CHECKPOINT_FULL'>SQLITE_CHECKPOINT_TRUNCATE</a></li>
<li><a href='#sqliteconfigcoveringindexscan'>SQLITE_CONFIG_COVERING_INDEX_SCAN</a></li>
<li><a href='#sqliteconfiggetmalloc'>SQLITE_CONFIG_GETMALLOC</a></li>
<li><a href='#sqliteconfiggetmutex'>SQLITE_CONFIG_GETMUTEX</a></li>
<li><a href='#sqliteconfiggetpcache'>SQLITE_CONFIG_GETPCACHE</a></li>
<li><a href='#sqliteconfiggetpcache2'>SQLITE_CONFIG_GETPCACHE2</a></li>
<li><a href='#sqliteconfigheap'>SQLITE_CONFIG_HEAP</a></li>
<li><a href='#sqliteconfiglog'>SQLITE_CONFIG_LOG</a></li>
<li><a href='#sqliteconfiglookaside'>SQLITE_CONFIG_LOOKASIDE</a></li>
<li><a href='#sqliteconfigmalloc'>SQLITE_CONFIG_MALLOC</a></li>
<li><a href='#sqliteconfigmemdbmaxsize'>SQLITE_CONFIG_MEMDB_MAXSIZE</a></li>
<li><a href='#sqliteconfigmemstatus'>SQLITE_CONFIG_MEMSTATUS</a></li>
<li><a href='#sqliteconfigmmapsize'>SQLITE_CONFIG_MMAP_SIZE</a></li>
<li><a href='#sqliteconfigmultithread'>SQLITE_CONFIG_MULTITHREAD</a></li>
<li><a href='#sqliteconfigmutex'>SQLITE_CONFIG_MUTEX</a></li>
<li><a href='#sqliteconfigpagecache'>SQLITE_CONFIG_PAGECACHE</a></li>
<li><a href='#sqliteconfigpcache'>SQLITE_CONFIG_PCACHE</a></li>
<li><a href='#sqliteconfigpcache2'>SQLITE_CONFIG_PCACHE2</a></li>
<li><a href='#sqliteconfigpcachehdrsz'>SQLITE_CONFIG_PCACHE_HDRSZ</a></li>
<li><a href='#sqliteconfigpmasz'>SQLITE_CONFIG_PMASZ</a></li>
<li><a href='#sqliteconfigrowidinview'>SQLITE_CONFIG_ROWID_IN_VIEW</a></li>
<li><a href='#sqliteconfigscratch'>SQLITE_CONFIG_SCRATCH</a></li>
<li><a href='#sqliteconfigserialized'>SQLITE_CONFIG_SERIALIZED</a></li>
<li><a href='#sqliteconfigsinglethread'>SQLITE_CONFIG_SINGLETHREAD</a></li>
<li><a href='#sqliteconfigsmallmalloc'>SQLITE_CONFIG_SMALL_MALLOC</a></li>
<li><a href='#sqliteconfigsorterrefsize'>SQLITE_CONFIG_SORTERREF_SIZE</a></li>
<li><a href='#sqliteconfigsqllog'>SQLITE_CONFIG_SQLLOG</a></li>
<li><a href='#sqliteconfigstmtjrnlspill'>SQLITE_CONFIG_STMTJRNL_SPILL</a></li>
<li><a href='#sqliteconfiguri'>SQLITE_CONFIG_URI</a></li>
<li><a href='#sqliteconfigwin32heapsize'>SQLITE_CONFIG_WIN32_HEAPSIZE</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_CONSTRAINT</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_CHECK</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_COMMITHOOK</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_DATATYPE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_FOREIGNKEY</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_FUNCTION</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_NOTNULL</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_PINNED</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_PRIMARYKEY</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_ROWID</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_TRIGGER</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_UNIQUE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_VTAB</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_COPY</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_CORRUPT</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CORRUPT_INDEX</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CORRUPT_SEQUENCE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CORRUPT_VTAB</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_INDEX</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TABLE</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TEMP_INDEX</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TEMP_TABLE</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TEMP_TRIGGER</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TEMP_VIEW</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TRIGGER</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_VIEW</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_VTABLE</a></li>
<li><a href='#sqlitedbconfigdefensive'>SQLITE_DBCONFIG_DEFENSIVE</a></li>
<li><a href='#sqlitedbconfigdqsddl'>SQLITE_DBCONFIG_DQS_DDL</a></li>
<li><a href='#sqlitedbconfigdqsdml'>SQLITE_DBCONFIG_DQS_DML</a></li>
<li><a href='#sqlitedbconfigenablefkey'>SQLITE_DBCONFIG_ENABLE_FKEY</a></li>
<li><a href='#sqlitedbconfigenablefts3tokenizer'>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</a></li>
<li><a href='#sqlitedbconfigenableloadextension'>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</a></li>
<li><a href='#sqlitedbconfigenableqpsg'>SQLITE_DBCONFIG_ENABLE_QPSG</a></li>
<li><a href='#sqlitedbconfigenabletrigger'>SQLITE_DBCONFIG_ENABLE_TRIGGER</a></li>
<li><a href='#sqlitedbconfigenableview'>SQLITE_DBCONFIG_ENABLE_VIEW</a></li>
<li><a href='#sqlitedbconfiglegacyaltertable'>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</a></li>
<li><a href='#sqlitedbconfiglegacyfileformat'>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</a></li>
<li><a href='#sqlitedbconfiglookaside'>SQLITE_DBCONFIG_LOOKASIDE</a></li>
<li><a href='#sqlitedbconfigmaindbname'>SQLITE_DBCONFIG_MAINDBNAME</a></li>
<li><a href='#SQLITE_DBCONFIG_DEFENSIVE'>SQLITE_DBCONFIG_MAX</a></li>
<li><a href='#sqlitedbconfignockptonclose'>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</a></li>
<li><a href='#sqlitedbconfigresetdatabase'>SQLITE_DBCONFIG_RESET_DATABASE</a></li>
<li><a href='#sqlitedbconfigreversescanorder'>SQLITE_DBCONFIG_REVERSE_SCANORDER</a></li>
<li><a href='#sqlitedbconfigstmtscanstatus'>SQLITE_DBCONFIG_STMT_SCANSTATUS</a></li>
<li><a href='#sqlitedbconfigtriggereqp'>SQLITE_DBCONFIG_TRIGGER_EQP</a></li>
<li><a href='#sqlitedbconfigtrustedschema'>SQLITE_DBCONFIG_TRUSTED_SCHEMA</a></li>
<li><a href='#sqlitedbconfigwritableschema'>SQLITE_DBCONFIG_WRITABLE_SCHEMA</a></li>
<li><a href='#sqlitedbstatuscachehit'>SQLITE_DBSTATUS_CACHE_HIT</a></li>
<li><a href='#sqlitedbstatuscachemiss'>SQLITE_DBSTATUS_CACHE_MISS</a></li>
<li><a href='#sqlitedbstatuscachespill'>SQLITE_DBSTATUS_CACHE_SPILL</a></li>
<li><a href='#sqlitedbstatuscacheused'>SQLITE_DBSTATUS_CACHE_USED</a></li>
<li><a href='#sqlitedbstatuscacheusedshared'>SQLITE_DBSTATUS_CACHE_USED_SHARED</a></li>
<li><a href='#sqlitedbstatuscachewrite'>SQLITE_DBSTATUS_CACHE_WRITE</a></li>
<li><a href='#sqlitedbstatusdeferredfks'>SQLITE_DBSTATUS_DEFERRED_FKS</a></li>
<li><a href='#sqlitedbstatuslookasidehit'>SQLITE_DBSTATUS_LOOKASIDE_HIT</a></li>
<li><a href='#sqlitedbstatuslookasidemissfull'>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</a></li>
<li><a href='#sqlitedbstatuslookasidemisssize'>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</a></li>
<li><a href='#sqlitedbstatuslookasideused'>SQLITE_DBSTATUS_LOOKASIDE_USED</a></li>
<li><a href='#SQLITE_DBSTATUS options'>SQLITE_DBSTATUS_MAX</a></li>
<li><a href='#sqlitedbstatusschemaused'>SQLITE_DBSTATUS_SCHEMA_USED</a></li>
<li><a href='#sqlitedbstatusstmtused'>SQLITE_DBSTATUS_STMT_USED</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DELETE</a></li>
<li><a href='#SQLITE_DENY'>SQLITE_DENY</a></li>
<li><a href='#SQLITE_DESERIALIZE_FREEONCLOSE'>SQLITE_DESERIALIZE_FREEONCLOSE</a></li>
<li><a href='#SQLITE_DESERIALIZE_FREEONCLOSE'>SQLITE_DESERIALIZE_READONLY</a></li>
<li><a href='#SQLITE_DESERIALIZE_FREEONCLOSE'>SQLITE_DESERIALIZE_RESIZEABLE</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DETACH</a></li>
<li><a href='#sqlitedeterministic'>SQLITE_DETERMINISTIC</a></li>
<li><a href='#sqlitedirectonly'>SQLITE_DIRECTONLY</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_DONE</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_INDEX</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TABLE</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TEMP_INDEX</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TEMP_TABLE</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TEMP_TRIGGER</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TEMP_VIEW</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TRIGGER</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_VIEW</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_VTABLE</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_EMPTY</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_ERROR</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_ERROR_MISSING_COLLSEQ</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_ERROR_RETRY</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_ERROR_SNAPSHOT</a></li>
<li><a href='#SQLITE_FAIL'>SQLITE_FAIL</a></li>
<li><a href='#sqlitefcntlbeginatomicwrite'>SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a></li>
<li><a href='#sqlitefcntlbusyhandler'>SQLITE_FCNTL_BUSYHANDLER</a></li>
<li><a href='#sqlitefcntlchunksize'>SQLITE_FCNTL_CHUNK_SIZE</a></li>
<li><a href='#sqlitefcntlckptdone'>SQLITE_FCNTL_CKPT_DONE</a></li>
<li><a href='#sqlitefcntlckptstart'>SQLITE_FCNTL_CKPT_START</a></li>
<li><a href='#sqlitefcntlcksmfile'>SQLITE_FCNTL_CKSM_FILE</a></li>
<li><a href='#sqlitefcntlcommitatomicwrite'>SQLITE_FCNTL_COMMIT_ATOMIC_WRITE</a></li>
<li><a href='#sqlitefcntlcommitphasetwo'>SQLITE_FCNTL_COMMIT_PHASETWO</a></li>
<li><a href='#sqlitefcntldataversion'>SQLITE_FCNTL_DATA_VERSION</a></li>
<li><a href='#sqlitefcntlexternalreader'>SQLITE_FCNTL_EXTERNAL_READER</a></li>
<li><a href='#sqlitefcntlfilepointer'>SQLITE_FCNTL_FILE_POINTER</a></li>
<li><a href='#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE'>SQLITE_FCNTL_GET_LOCKPROXYFILE</a></li>
<li><a href='#sqlitefcntlhasmoved'>SQLITE_FCNTL_HAS_MOVED</a></li>
<li><a href='#sqlitefcntljournalpointer'>SQLITE_FCNTL_JOURNAL_POINTER</a></li>
<li><a href='#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE'>SQLITE_FCNTL_LAST_ERRNO</a></li>
<li><a href='#sqlitefcntllockstate'>SQLITE_FCNTL_LOCKSTATE</a></li>
<li><a href='#sqlitefcntllocktimeout'>SQLITE_FCNTL_LOCK_TIMEOUT</a></li>
<li><a href='#sqlitefcntlmmapsize'>SQLITE_FCNTL_MMAP_SIZE</a></li>
<li><a href='#sqlitefcntloverwrite'>SQLITE_FCNTL_OVERWRITE</a></li>
<li><a href='#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE'>SQLITE_FCNTL_PDB</a></li>
<li><a href='#sqlitefcntlpersistwal'>SQLITE_FCNTL_PERSIST_WAL</a></li>
<li><a href='#sqlitefcntlpowersafeoverwrite'>SQLITE_FCNTL_POWERSAFE_OVERWRITE</a></li>
<li><a href='#sqlitefcntlpragma'>SQLITE_FCNTL_PRAGMA</a></li>
<li><a href='#sqlitefcntlrbu'>SQLITE_FCNTL_RBU</a></li>
<li><a href='#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE'>SQLITE_FCNTL_RESERVE_BYTES</a></li>
<li><a href='#sqlitefcntlresetcache'>SQLITE_FCNTL_RESET_CACHE</a></li>
<li><a href='#sqlitefcntlrollbackatomicwrite'>SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE</a></li>
<li><a href='#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE'>SQLITE_FCNTL_SET_LOCKPROXYFILE</a></li>
<li><a href='#sqlitefcntlsizehint'>SQLITE_FCNTL_SIZE_HINT</a></li>
<li><a href='#sqlitefcntlsizelimit'>SQLITE_FCNTL_SIZE_LIMIT</a></li>
<li><a href='#sqlitefcntlsync'>SQLITE_FCNTL_SYNC</a></li>
<li><a href='#sqlitefcntlsyncomitted'>SQLITE_FCNTL_SYNC_OMITTED</a></li>
<li><a href='#sqlitefcntltempfilename'>SQLITE_FCNTL_TEMPFILENAME</a></li>
<li><a href='#sqlitefcntltrace'>SQLITE_FCNTL_TRACE</a></li>
<li><a href='#sqlitefcntlvfsname'>SQLITE_FCNTL_VFSNAME</a></li>
<li><a href='#sqlitefcntlvfspointer'>SQLITE_FCNTL_VFS_POINTER</a></li>
<li><a href='#sqlitefcntlwalblock'>SQLITE_FCNTL_WAL_BLOCK</a></li>
<li><a href='#sqlitefcntlwin32avretry'>SQLITE_FCNTL_WIN32_AV_RETRY</a></li>
<li><a href='#sqlitefcntlwin32gethandle'>SQLITE_FCNTL_WIN32_GET_HANDLE</a></li>
<li><a href='#sqlitefcntlwin32sethandle'>SQLITE_FCNTL_WIN32_SET_HANDLE</a></li>
<li><a href='#sqlitefcntlzipvfs'>SQLITE_FCNTL_ZIPVFS</a></li>
<li><a href='#SQLITE_BLOB'>SQLITE_FLOAT</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_FORMAT</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_FULL</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_FUNCTION</a></li>
<li><a href='#SQLITE_DENY'>SQLITE_IGNORE</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_EQ</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_FUNCTION</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_GE</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_GLOB</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_GT</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_IS</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_ISNOT</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_ISNOTNULL</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_ISNULL</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_LE</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_LIKE</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_LIMIT</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_LT</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_MATCH</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_NE</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_OFFSET</a></li>
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_REGEXP</a></li>
<li><a href='#SQLITE_INDEX_SCAN_UNIQUE'>SQLITE_INDEX_SCAN_UNIQUE</a></li>
<li><a href='#sqliteinnocuous'>SQLITE_INNOCUOUS</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_INSERT</a></li>
<li><a href='#SQLITE_BLOB'>SQLITE_INTEGER</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_INTERNAL</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_INTERRUPT</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC16K</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC1K</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC2K</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC32K</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC4K</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC512</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC64K</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC8K</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_BATCH_ATOMIC</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_IMMUTABLE</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_POWERSAFE_OVERWRITE</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_SAFE_APPEND</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_SEQUENTIAL</a></li>
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_IOERR</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_ACCESS</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_AUTH</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_BEGIN_ATOMIC</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_BLOCKED</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_CHECKRESERVEDLOCK</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_CLOSE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_COMMIT_ATOMIC</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_CONVPATH</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_CORRUPTFS</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_DATA</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_DELETE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_DELETE_NOENT</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_DIR_CLOSE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_DIR_FSYNC</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_FSTAT</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_FSYNC</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_GETTEMPPATH</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_IN_PAGE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_LOCK</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_MMAP</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_NOMEM</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_RDLOCK</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_READ</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_ROLLBACK_ATOMIC</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SEEK</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SHMLOCK</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SHMMAP</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SHMOPEN</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SHMSIZE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SHORT_READ</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_TRUNCATE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_UNLOCK</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_VNODE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_WRITE</a></li>
<li><a href='#sqlitelimitattached'>SQLITE_LIMIT_ATTACHED</a></li>
<li><a href='#sqlitelimitcolumn'>SQLITE_LIMIT_COLUMN</a></li>
<li><a href='#sqlitelimitcompoundselect'>SQLITE_LIMIT_COMPOUND_SELECT</a></li>
<li><a href='#sqlitelimitexprdepth'>SQLITE_LIMIT_EXPR_DEPTH</a></li>
<li><a href='#sqlitelimitfunctionarg'>SQLITE_LIMIT_FUNCTION_ARG</a></li>
<li><a href='#sqlitelimitlength'>SQLITE_LIMIT_LENGTH</a></li>
<li><a href='#sqlitelimitlikepatternlength'>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</a></li>
<li><a href='#sqlitelimitsqllength'>SQLITE_LIMIT_SQL_LENGTH</a></li>
<li><a href='#sqlitelimittriggerdepth'>SQLITE_LIMIT_TRIGGER_DEPTH</a></li>
<li><a href='#sqlitelimitvariablenumber'>SQLITE_LIMIT_VARIABLE_NUMBER</a></li>
<li><a href='#sqlitelimitvdbeop'>SQLITE_LIMIT_VDBE_OP</a></li>
<li><a href='#sqlitelimitworkerthreads'>SQLITE_LIMIT_WORKER_THREADS</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_LOCKED</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_LOCKED_SHAREDCACHE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_LOCKED_VTAB</a></li>
<li><a href='#SQLITE_LOCK_EXCLUSIVE'>SQLITE_LOCK_EXCLUSIVE</a></li>
<li><a href='#SQLITE_LOCK_EXCLUSIVE'>SQLITE_LOCK_NONE</a></li>
<li><a href='#SQLITE_LOCK_EXCLUSIVE'>SQLITE_LOCK_PENDING</a></li>
<li><a href='#SQLITE_LOCK_EXCLUSIVE'>SQLITE_LOCK_RESERVED</a></li>
<li><a href='#SQLITE_LOCK_EXCLUSIVE'>SQLITE_LOCK_SHARED</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_MISMATCH</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_MISUSE</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_FAST</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_RECURSIVE</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_APP1</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_APP2</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_APP3</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_LRU</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_LRU2</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_MAIN</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_MEM</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_MEM2</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_OPEN</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_PMEM</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_PRNG</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_VFS1</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_VFS2</a></li>
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_VFS3</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_NOLFS</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_NOMEM</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_NOTADB</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_NOTFOUND</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_NOTICE</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_NOTICE_RBU</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_NOTICE_RECOVER_ROLLBACK</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_NOTICE_RECOVER_WAL</a></li>
<li><a href='#SQLITE_BLOB'>SQLITE_NULL</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_OK</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_OK_LOAD_PERMANENTLY</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_OK_SYMLINK</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_AUTOPROXY</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_CREATE</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_DELETEONCLOSE</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_EXCLUSIVE</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_EXRESCODE</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_FULLMUTEX</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_MAIN_DB</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_MAIN_JOURNAL</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_MEMORY</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_NOFOLLOW</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_NOMUTEX</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_PRIVATECACHE</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_READONLY</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_READWRITE</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_SHAREDCACHE</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_SUBJOURNAL</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_SUPER_JOURNAL</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_TEMP_DB</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_TEMP_JOURNAL</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_TRANSIENT_DB</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_URI</a></li>
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_WAL</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_PERM</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_PRAGMA</a></li>
<li><a href='#sqlitepreparenormalize'>SQLITE_PREPARE_NORMALIZE</a></li>
<li><a href='#sqlitepreparenovtab'>SQLITE_PREPARE_NO_VTAB</a></li>
<li><a href='#sqlitepreparepersistent'>SQLITE_PREPARE_PERSISTENT</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_PROTOCOL</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_RANGE</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_READ</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_READONLY</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_CANTINIT</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_CANTLOCK</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_DBMOVED</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_DIRECTORY</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_RECOVERY</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_ROLLBACK</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_RECURSIVE</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_REINDEX</a></li>
<li><a href='#SQLITE_FAIL'>SQLITE_REPLACE</a></li>
<li><a href='#sqliteresultsubtype'>SQLITE_RESULT_SUBTYPE</a></li>
<li><a href='#SQLITE_FAIL'>SQLITE_ROLLBACK</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_ROW</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_SAVEPOINT</a></li>
<li><a href='#SQLITE_SCANSTAT_COMPLEX'>SQLITE_SCANSTAT_COMPLEX</a></li>
<li><a href='#sqlitescanstatest'>SQLITE_SCANSTAT_EST</a></li>
<li><a href='#sqlitescanstatexplain'>SQLITE_SCANSTAT_EXPLAIN</a></li>
<li><a href='#sqlitescanstatname'>SQLITE_SCANSTAT_NAME</a></li>
<li><a href='#sqlitescanstatncycle'>SQLITE_SCANSTAT_NCYCLE</a></li>
<li><a href='#sqlitescanstatnloop'>SQLITE_SCANSTAT_NLOOP</a></li>
<li><a href='#sqlitescanstatnvisit'>SQLITE_SCANSTAT_NVISIT</a></li>
<li><a href='#sqlitescanstatparentid'>SQLITE_SCANSTAT_PARENTID</a></li>
<li><a href='#sqlitescanstatselectid'>SQLITE_SCANSTAT_SELECTID</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_SCHEMA</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_SELECT</a></li>
<li><a href='#SQLITE_SERIALIZE_NOCOPY'>SQLITE_SERIALIZE_NOCOPY</a></li>
<li><a href='#SQLITE_SHM_EXCLUSIVE'>SQLITE_SHM_EXCLUSIVE</a></li>
<li><a href='#SQLITE_SHM_EXCLUSIVE'>SQLITE_SHM_LOCK</a></li>
<li><a href='#SQLITE_SHM_NLOCK'>SQLITE_SHM_NLOCK</a></li>
<li><a href='#SQLITE_SHM_EXCLUSIVE'>SQLITE_SHM_SHARED</a></li>
<li><a href='#SQLITE_SHM_EXCLUSIVE'>SQLITE_SHM_UNLOCK</a></li>
<li><a href='#SQLITE_SOURCE_ID'>SQLITE_SOURCE_ID</a></li>
<li><a href='#SQLITE_STATIC'>SQLITE_STATIC</a></li>
<li><a href='#sqlitestatusmalloccount'>SQLITE_STATUS_MALLOC_COUNT</a></li>
<li><a href='#sqlitestatusmallocsize'>SQLITE_STATUS_MALLOC_SIZE</a></li>
<li><a href='#sqlitestatusmemoryused'>SQLITE_STATUS_MEMORY_USED</a></li>
<li><a href='#sqlitestatuspagecacheoverflow'>SQLITE_STATUS_PAGECACHE_OVERFLOW</a></li>
<li><a href='#sqlitestatuspagecachesize'>SQLITE_STATUS_PAGECACHE_SIZE</a></li>
<li><a href='#sqlitestatuspagecacheused'>SQLITE_STATUS_PAGECACHE_USED</a></li>
<li><a href='#sqlitestatusparserstack'>SQLITE_STATUS_PARSER_STACK</a></li>
<li><a href='#sqlitestatusscratchoverflow'>SQLITE_STATUS_SCRATCH_OVERFLOW</a></li>
<li><a href='#sqlitestatusscratchsize'>SQLITE_STATUS_SCRATCH_SIZE</a></li>
<li><a href='#sqlitestatusscratchused'>SQLITE_STATUS_SCRATCH_USED</a></li>
<li><a href='#sqlitestmtstatusautoindex'>SQLITE_STMTSTATUS_AUTOINDEX</a></li>
<li><a href='#SQLITE_STMTSTATUS counter'>SQLITE_STMTSTATUS_FILTER_HIT</a></li>
<li><a href='#sqlitestmtstatusfiltermiss'>SQLITE_STMTSTATUS_FILTER_MISS</a></li>
<li><a href='#sqlitestmtstatusfullscanstep'>SQLITE_STMTSTATUS_FULLSCAN_STEP</a></li>
<li><a href='#sqlitestmtstatusmemused'>SQLITE_STMTSTATUS_MEMUSED</a></li>
<li><a href='#sqlitestmtstatusreprepare'>SQLITE_STMTSTATUS_REPREPARE</a></li>
<li><a href='#sqlitestmtstatusrun'>SQLITE_STMTSTATUS_RUN</a></li>
<li><a href='#sqlitestmtstatussort'>SQLITE_STMTSTATUS_SORT</a></li>
<li><a href='#sqlitestmtstatusvmstep'>SQLITE_STMTSTATUS_VM_STEP</a></li>
<li><a href='#sqlitesubtype'>SQLITE_SUBTYPE</a></li>
<li><a href='#SQLITE_SYNC_DATAONLY'>SQLITE_SYNC_DATAONLY</a></li>
<li><a href='#SQLITE_SYNC_DATAONLY'>SQLITE_SYNC_FULL</a></li>
<li><a href='#SQLITE_SYNC_DATAONLY'>SQLITE_SYNC_NORMAL</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_ALWAYS</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_ASSERT</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_BITVEC_TEST</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_BYTEORDER</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_EXPLAIN_STMT</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_FAULT_INSTALL</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_FIRST</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_FK_NO_ACTION</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_IMPOSTER</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_INTERNAL_FUNCTIONS</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_ISINIT</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_ISKEYWORD</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_JSON_SELFCHECK</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_LAST</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_LOCALTIME_FAULT</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_LOGEST</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_NEVER_CORRUPT</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_OPTIMIZATIONS</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PARSER_COVERAGE</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PENDING_BYTE</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PRNG_RESET</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PRNG_RESTORE</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PRNG_SAVE</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PRNG_SEED</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_RESERVE</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_RESULT_INTREAL</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_SCRATCHMALLOC</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_SEEK_COUNT</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_SORTER_MMAP</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_TRACEFLAGS</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_TUNE</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_USELONGDOUBLE</a></li>
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_VDBE_COVERAGE</a></li>
<li><a href='#SQLITE_BLOB'>SQLITE_TEXT</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_TOOBIG</a></li>
<li><a href='#SQLITE_TRACE'>SQLITE_TRACE</a></li>
<li><a href='#sqlitetraceclose'>SQLITE_TRACE_CLOSE</a></li>
<li><a href='#sqlitetraceprofile'>SQLITE_TRACE_PROFILE</a></li>
<li><a href='#sqlitetracerow'>SQLITE_TRACE_ROW</a></li>
<li><a href='#sqlitetracestmt'>SQLITE_TRACE_STMT</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_TRANSACTION</a></li>
<li><a href='#SQLITE_STATIC'>SQLITE_TRANSIENT</a></li>
<li><a href='#sqlitetxnnone'>SQLITE_TXN_NONE</a></li>
<li><a href='#sqlitetxnread'>SQLITE_TXN_READ</a></li>
<li><a href='#sqlitetxnwrite'>SQLITE_TXN_WRITE</a></li>
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_UPDATE</a></li>
<li><a href='#SQLITE_ANY'>SQLITE_UTF16</a></li>
<li><a href='#SQLITE_ANY'>SQLITE_UTF16BE</a></li>
<li><a href='#SQLITE_ANY'>SQLITE_UTF16LE</a></li>
<li><a href='#SQLITE_ANY'>SQLITE_UTF16_ALIGNED</a></li>
<li><a href='#SQLITE_ANY'>SQLITE_UTF8</a></li>
<li><a href='#SQLITE_SOURCE_ID'>SQLITE_VERSION</a></li>
<li><a href='#SQLITE_SOURCE_ID'>SQLITE_VERSION_NUMBER</a></li>
<li><a href='#sqlitevtabconstraintsupport'>SQLITE_VTAB_CONSTRAINT_SUPPORT</a></li>
<li><a href='#sqlitevtabdirectonly'>SQLITE_VTAB_DIRECTONLY</a></li>
<li><a href='#sqlitevtabinnocuous'>SQLITE_VTAB_INNOCUOUS</a></li>
<li><a href='#sqlitevtabusesallschemas'>SQLITE_VTAB_USES_ALL_SCHEMAS</a></li>
<li><a href='#SQLITE_ABORT'>SQLITE_WARNING</a></li>
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_WARNING_AUTOINDEX</a></li>
<li><a href='#SQLITE_WIN32_DATA_DIRECTORY_TYPE'>SQLITE_WIN32_DATA_DIRECTORY_TYPE</a></li>
<li><a href='#SQLITE_WIN32_DATA_DIRECTORY_TYPE'>SQLITE_WIN32_TEMP_DIRECTORY_TYPE</a></li>
</ul>
</div>
<hr>
<h2>List Of Functions:</h2>
<p>Note: Functions marked with "<small><i>(exp)</i></small>"
are <a href="capi3ref.html">experimental</a> and functions whose names are
<s>struck through</s> are <a href="capi3ref.html">deprecated</a>.</p>
<!-- number of functions: 288 -->
<!-- number of deprecated functions: 9 -->
<!-- number of experimental functions: 0 -->
<div class='columns' style='columns: 15em auto;'>
<ul style='padding-top:0;'>
<li><a href='#sqlite3_aggregate_context'>sqlite3_aggregate_context</a></li>
<li><s>sqlite3_aggregate_count</s></li>
<li><a href='#sqlite3_auto_extension'>sqlite3_auto_extension</a></li>
<li><a href='#sqlite3_autovacuum_pages'>sqlite3_autovacuum_pages</a></li>
<li><a href='#sqlite3backupfinish'>sqlite3_backup_finish</a></li>
<li><a href='#sqlite3backupinit'>sqlite3_backup_init</a></li>
<li><a href='#sqlite3backuppagecount'>sqlite3_backup_pagecount</a></li>
<li><a href='#sqlite3backupremaining'>sqlite3_backup_remaining</a></li>
<li><a href='#sqlite3backupstep'>sqlite3_backup_step</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_blob</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_blob64</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_double</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_int</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_int64</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_null</a></li>
<li><a href='#sqlite3_bind_parameter_count'>sqlite3_bind_parameter_count</a></li>
<li><a href='#sqlite3_bind_parameter_index'>sqlite3_bind_parameter_index</a></li>
<li><a href='#sqlite3_bind_parameter_name'>sqlite3_bind_parameter_name</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_pointer</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text16</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text64</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_value</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_zeroblob</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_zeroblob64</a></li>
<li><a href='#sqlite3_blob_bytes'>sqlite3_blob_bytes</a></li>
<li><a href='#sqlite3_blob_close'>sqlite3_blob_close</a></li>
<li><a href='#sqlite3_blob_open'>sqlite3_blob_open</a></li>
<li><a href='#sqlite3_blob_read'>sqlite3_blob_read</a></li>
<li><a href='#sqlite3_blob_reopen'>sqlite3_blob_reopen</a></li>
<li><a href='#sqlite3_blob_write'>sqlite3_blob_write</a></li>
<li><a href='#sqlite3_busy_handler'>sqlite3_busy_handler</a></li>
<li><a href='#sqlite3_busy_timeout'>sqlite3_busy_timeout</a></li>
<li><a href='#sqlite3_cancel_auto_extension'>sqlite3_cancel_auto_extension</a></li>
<li><a href='#sqlite3_changes'>sqlite3_changes</a></li>
<li><a href='#sqlite3_changes'>sqlite3_changes64</a></li>
<li><a href='#sqlite3_clear_bindings'>sqlite3_clear_bindings</a></li>
<li><a href='#sqlite3_close'>sqlite3_close</a></li>
<li><a href='#sqlite3_close'>sqlite3_close_v2</a></li>
<li><a href='#sqlite3_collation_needed'>sqlite3_collation_needed</a></li>
<li><a href='#sqlite3_collation_needed'>sqlite3_collation_needed16</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_blob</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_bytes</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_bytes16</a></li>
<li><a href='#sqlite3_column_count'>sqlite3_column_count</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_database_name</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_database_name16</a></li>
<li><a href='#sqlite3_column_decltype'>sqlite3_column_decltype</a></li>
<li><a href='#sqlite3_column_decltype'>sqlite3_column_decltype16</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_double</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_int</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_int64</a></li>
<li><a href='#sqlite3_column_name'>sqlite3_column_name</a></li>
<li><a href='#sqlite3_column_name'>sqlite3_column_name16</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_origin_name</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_origin_name16</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_table_name</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_table_name16</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_text</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_text16</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_type</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_value</a></li>
<li><a href='#sqlite3_commit_hook'>sqlite3_commit_hook</a></li>
<li><a href='#sqlite3_compileoption_get'>sqlite3_compileoption_get</a></li>
<li><a href='#sqlite3_compileoption_get'>sqlite3_compileoption_used</a></li>
<li><a href='#sqlite3_complete'>sqlite3_complete</a></li>
<li><a href='#sqlite3_complete'>sqlite3_complete16</a></li>
<li><a href='#sqlite3_config'>sqlite3_config</a></li>
<li><a href='#sqlite3_context_db_handle'>sqlite3_context_db_handle</a></li>
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation</a></li>
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation16</a></li>
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation_v2</a></li>
<li><a href='#sqlite3_create_filename'>sqlite3_create_filename</a></li>
<li><a href='#sqlite3_create_function'>sqlite3_create_function</a></li>
<li><a href='#sqlite3_create_function'>sqlite3_create_function16</a></li>
<li><a href='#sqlite3_create_function'>sqlite3_create_function_v2</a></li>
<li><a href='#sqlite3_create_module'>sqlite3_create_module</a></li>
<li><a href='#sqlite3_create_module'>sqlite3_create_module_v2</a></li>
<li><a href='#sqlite3_create_function'>sqlite3_create_window_function</a></li>
<li><a href='#sqlite3_data_count'>sqlite3_data_count</a></li>
<li><a href='#sqlite3_database_file_object'>sqlite3_database_file_object</a></li>
<li><a href='#sqlite3_db_cacheflush'>sqlite3_db_cacheflush</a></li>
<li><a href='#sqlite3_db_config'>sqlite3_db_config</a></li>
<li><a href='#sqlite3_db_filename'>sqlite3_db_filename</a></li>
<li><a href='#sqlite3_db_handle'>sqlite3_db_handle</a></li>
<li><a href='#sqlite3_db_mutex'>sqlite3_db_mutex</a></li>
<li><a href='#sqlite3_db_name'>sqlite3_db_name</a></li>
<li><a href='#sqlite3_db_readonly'>sqlite3_db_readonly</a></li>
<li><a href='#sqlite3_db_release_memory'>sqlite3_db_release_memory</a></li>
<li><a href='#sqlite3_db_status'>sqlite3_db_status</a></li>
<li><a href='#sqlite3_declare_vtab'>sqlite3_declare_vtab</a></li>
<li><a href='#sqlite3_deserialize'>sqlite3_deserialize</a></li>
<li><a href='#sqlite3_drop_modules'>sqlite3_drop_modules</a></li>
<li><a href='#sqlite3_enable_load_extension'>sqlite3_enable_load_extension</a></li>
<li><a href='#sqlite3_enable_shared_cache'>sqlite3_enable_shared_cache</a></li>
<li><a href='#sqlite3_errcode'>sqlite3_errcode</a></li>
<li><a href='#sqlite3_errcode'>sqlite3_errmsg</a></li>
<li><a href='#sqlite3_errcode'>sqlite3_errmsg16</a></li>
<li><a href='#sqlite3_errcode'>sqlite3_error_offset</a></li>
<li><a href='#sqlite3_errcode'>sqlite3_errstr</a></li>
<li><a href='#sqlite3_exec'>sqlite3_exec</a></li>
<li><a href='#sqlite3_expanded_sql'>sqlite3_expanded_sql</a></li>
<li><s>sqlite3_expired</s></li>
<li><a href='#sqlite3_errcode'>sqlite3_extended_errcode</a></li>
<li><a href='#sqlite3_extended_result_codes'>sqlite3_extended_result_codes</a></li>
<li><a href='#sqlite3_file_control'>sqlite3_file_control</a></li>
<li><a href='#sqlite3_filename_database'>sqlite3_filename_database</a></li>
<li><a href='#sqlite3_filename_database'>sqlite3_filename_journal</a></li>
<li><a href='#sqlite3_filename_database'>sqlite3_filename_wal</a></li>
<li><a href='#sqlite3_finalize'>sqlite3_finalize</a></li>
<li><a href='#sqlite3_free'>sqlite3_free</a></li>
<li><a href='#sqlite3_create_filename'>sqlite3_free_filename</a></li>
<li><a href='#sqlite3_free_table'>sqlite3_free_table</a></li>
<li><a href='#sqlite3_get_autocommit'>sqlite3_get_autocommit</a></li>
<li><a href='#sqlite3_get_auxdata'>sqlite3_get_auxdata</a></li>
<li><a href='#sqlite3_get_clientdata'>sqlite3_get_clientdata</a></li>
<li><a href='#sqlite3_free_table'>sqlite3_get_table</a></li>
<li><s>sqlite3_global_recover</s></li>
<li><a href='#sqlite3_hard_heap_limit64'>sqlite3_hard_heap_limit64</a></li>
<li><a href='#sqlite3_initialize'>sqlite3_initialize</a></li>
<li><a href='#sqlite3_interrupt'>sqlite3_interrupt</a></li>
<li><a href='#sqlite3_interrupt'>sqlite3_is_interrupted</a></li>
<li><a href='#sqlite3_keyword_check'>sqlite3_keyword_check</a></li>
<li><a href='#sqlite3_keyword_check'>sqlite3_keyword_count</a></li>
<li><a href='#sqlite3_keyword_check'>sqlite3_keyword_name</a></li>
<li><a href='#sqlite3_last_insert_rowid'>sqlite3_last_insert_rowid</a></li>
<li><a href='#sqlite3_libversion'>sqlite3_libversion</a></li>
<li><a href='#sqlite3_libversion'>sqlite3_libversion_number</a></li>
<li><a href='#sqlite3_limit'>sqlite3_limit</a></li>
<li><a href='#sqlite3_load_extension'>sqlite3_load_extension</a></li>
<li><a href='#sqlite3_log'>sqlite3_log</a></li>
<li><a href='#sqlite3_free'>sqlite3_malloc</a></li>
<li><a href='#sqlite3_free'>sqlite3_malloc64</a></li>
<li><s>sqlite3_memory_alarm</s></li>
<li><a href='#sqlite3_memory_highwater'>sqlite3_memory_highwater</a></li>
<li><a href='#sqlite3_memory_highwater'>sqlite3_memory_used</a></li>
<li><a href='#sqlite3_mprintf'>sqlite3_mprintf</a></li>
<li><a href='#sqlite3_free'>sqlite3_msize</a></li>
<li><a href='#sqlite3_mutex_alloc'>sqlite3_mutex_alloc</a></li>
<li><a href='#sqlite3_mutex_alloc'>sqlite3_mutex_enter</a></li>
<li><a href='#sqlite3_mutex_alloc'>sqlite3_mutex_free</a></li>
<li><a href='#sqlite3_mutex_held'>sqlite3_mutex_held</a></li>
<li><a href='#sqlite3_mutex_alloc'>sqlite3_mutex_leave</a></li>
<li><a href='#sqlite3_mutex_held'>sqlite3_mutex_notheld</a></li>
<li><a href='#sqlite3_mutex_alloc'>sqlite3_mutex_try</a></li>
<li><a href='#sqlite3_next_stmt'>sqlite3_next_stmt</a></li>
<li><a href='#sqlite3_expanded_sql'>sqlite3_normalized_sql</a></li>
<li><a href='#sqlite3_open'>sqlite3_open</a></li>
<li><a href='#sqlite3_open'>sqlite3_open16</a></li>
<li><a href='#sqlite3_open'>sqlite3_open_v2</a></li>
<li><a href='#sqlite3_initialize'>sqlite3_os_end</a></li>
<li><a href='#sqlite3_initialize'>sqlite3_os_init</a></li>
<li><a href='#sqlite3_overload_function'>sqlite3_overload_function</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare16</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v2</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v3</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v2</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v3</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_blobwrite</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_count</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_depth</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_hook</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_new</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_old</a></li>
<li><s>sqlite3_profile</s></li>
<li><a href='#sqlite3_progress_handler'>sqlite3_progress_handler</a></li>
<li><a href='#sqlite3_randomness'>sqlite3_randomness</a></li>
<li><a href='#sqlite3_free'>sqlite3_realloc</a></li>
<li><a href='#sqlite3_free'>sqlite3_realloc64</a></li>
<li><a href='#sqlite3_release_memory'>sqlite3_release_memory</a></li>
<li><a href='#sqlite3_reset'>sqlite3_reset</a></li>
<li><a href='#sqlite3_reset_auto_extension'>sqlite3_reset_auto_extension</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_blob</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_blob64</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_double</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_error</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_error16</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_code</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_nomem</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_toobig</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_int</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_int64</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_null</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_pointer</a></li>
<li><a href='#sqlite3_result_subtype'>sqlite3_result_subtype</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_text</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16be</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16le</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_text64</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_value</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_zeroblob</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_zeroblob64</a></li>
<li><a href='#sqlite3_commit_hook'>sqlite3_rollback_hook</a></li>
<li><a href='#sqlite3_serialize'>sqlite3_serialize</a></li>
<li><a href='#sqlite3_set_authorizer'>sqlite3_set_authorizer</a></li>
<li><a href='#sqlite3_get_auxdata'>sqlite3_set_auxdata</a></li>
<li><a href='#sqlite3_get_clientdata'>sqlite3_set_clientdata</a></li>
<li><a href='#sqlite3_set_last_insert_rowid'>sqlite3_set_last_insert_rowid</a></li>
<li><a href='#sqlite3_initialize'>sqlite3_shutdown</a></li>
<li><a href='#sqlite3_sleep'>sqlite3_sleep</a></li>
<li><a href='#sqlite3_snapshot_cmp'>sqlite3_snapshot_cmp</a></li>
<li><a href='#sqlite3_snapshot_free'>sqlite3_snapshot_free</a></li>
<li><a href='#sqlite3_snapshot_get'>sqlite3_snapshot_get</a></li>
<li><a href='#sqlite3_snapshot_open'>sqlite3_snapshot_open</a></li>
<li><a href='#sqlite3_snapshot_recover'>sqlite3_snapshot_recover</a></li>
<li><a href='#sqlite3_mprintf'>sqlite3_snprintf</a></li>
<li><s>sqlite3_soft_heap_limit</s></li>
<li><a href='#sqlite3_hard_heap_limit64'>sqlite3_soft_heap_limit64</a></li>
<li><a href='#sqlite3_libversion'>sqlite3_sourceid</a></li>
<li><a href='#sqlite3_expanded_sql'>sqlite3_sql</a></li>
<li><a href='#sqlite3_status'>sqlite3_status</a></li>
<li><a href='#sqlite3_status'>sqlite3_status64</a></li>
<li><a href='#sqlite3_step'>sqlite3_step</a></li>
<li><a href='#sqlite3_stmt_busy'>sqlite3_stmt_busy</a></li>
<li><a href='#sqlite3_stmt_explain'>sqlite3_stmt_explain</a></li>
<li><a href='#sqlite3_stmt_isexplain'>sqlite3_stmt_isexplain</a></li>
<li><a href='#sqlite3_stmt_readonly'>sqlite3_stmt_readonly</a></li>
<li><a href='#sqlite3_stmt_scanstatus'>sqlite3_stmt_scanstatus</a></li>
<li><a href='#sqlite3_stmt_scanstatus_reset'>sqlite3_stmt_scanstatus_reset</a></li>
<li><a href='#sqlite3_stmt_scanstatus'>sqlite3_stmt_scanstatus_v2</a></li>
<li><a href='#sqlite3_stmt_status'>sqlite3_stmt_status</a></li>
<li><a href='#sqlite3_str_append'>sqlite3_str_append</a></li>
<li><a href='#sqlite3_str_append'>sqlite3_str_appendall</a></li>
<li><a href='#sqlite3_str_append'>sqlite3_str_appendchar</a></li>
<li><a href='#sqlite3_str_append'>sqlite3_str_appendf</a></li>
<li><a href='#sqlite3_str_errcode'>sqlite3_str_errcode</a></li>
<li><a href='#sqlite3_str_finish'>sqlite3_str_finish</a></li>
<li><a href='#sqlite3_str_errcode'>sqlite3_str_length</a></li>
<li><a href='#sqlite3_str_new'>sqlite3_str_new</a></li>
<li><a href='#sqlite3_str_append'>sqlite3_str_reset</a></li>
<li><a href='#sqlite3_str_errcode'>sqlite3_str_value</a></li>
<li><a href='#sqlite3_str_append'>sqlite3_str_vappendf</a></li>
<li><a href='#sqlite3_strglob'>sqlite3_strglob</a></li>
<li><a href='#sqlite3_stricmp'>sqlite3_stricmp</a></li>
<li><a href='#sqlite3_strlike'>sqlite3_strlike</a></li>
<li><a href='#sqlite3_stricmp'>sqlite3_strnicmp</a></li>
<li><a href='#sqlite3_system_errno'>sqlite3_system_errno</a></li>
<li><a href='#sqlite3_table_column_metadata'>sqlite3_table_column_metadata</a></li>
<li><a href='#sqlite3_test_control'>sqlite3_test_control</a></li>
<li><s>sqlite3_thread_cleanup</s></li>
<li><a href='#sqlite3_threadsafe'>sqlite3_threadsafe</a></li>
<li><a href='#sqlite3_total_changes'>sqlite3_total_changes</a></li>
<li><a href='#sqlite3_total_changes'>sqlite3_total_changes64</a></li>
<li><s>sqlite3_trace</s></li>
<li><a href='#sqlite3_trace_v2'>sqlite3_trace_v2</a></li>
<li><s>sqlite3_transfer_bindings</s></li>
<li><a href='#sqlite3_txn_state'>sqlite3_txn_state</a></li>
<li><a href='#sqlite3_unlock_notify'>sqlite3_unlock_notify</a></li>
<li><a href='#sqlite3_update_hook'>sqlite3_update_hook</a></li>
<li><a href='#sqlite3_uri_boolean'>sqlite3_uri_boolean</a></li>
<li><a href='#sqlite3_uri_boolean'>sqlite3_uri_int64</a></li>
<li><a href='#sqlite3_uri_boolean'>sqlite3_uri_key</a></li>
<li><a href='#sqlite3_uri_boolean'>sqlite3_uri_parameter</a></li>
<li><a href='#sqlite3_user_data'>sqlite3_user_data</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_blob</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_bytes</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_bytes16</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_double</a></li>
<li><a href='#sqlite3_value_dup'>sqlite3_value_dup</a></li>
<li><a href='#sqlite3_value_encoding'>sqlite3_value_encoding</a></li>
<li><a href='#sqlite3_value_dup'>sqlite3_value_free</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_frombind</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_int</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_int64</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_nochange</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_numeric_type</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_pointer</a></li>
<li><a href='#sqlite3_value_subtype'>sqlite3_value_subtype</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_text</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16be</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16le</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_type</a></li>
<li><a href='#sqlite3_libversion'>sqlite3_version</a></li>
<li><a href='#sqlite3_vfs_find'>sqlite3_vfs_find</a></li>
<li><a href='#sqlite3_vfs_find'>sqlite3_vfs_register</a></li>
<li><a href='#sqlite3_vfs_find'>sqlite3_vfs_unregister</a></li>
<li><a href='#sqlite3_mprintf'>sqlite3_vmprintf</a></li>
<li><a href='#sqlite3_mprintf'>sqlite3_vsnprintf</a></li>
<li><a href='#sqlite3_vtab_collation'>sqlite3_vtab_collation</a></li>
<li><a href='#sqlite3_vtab_config'>sqlite3_vtab_config</a></li>
<li><a href='#sqlite3_vtab_distinct'>sqlite3_vtab_distinct</a></li>
<li><a href='#sqlite3_vtab_in'>sqlite3_vtab_in</a></li>
<li><a href='#sqlite3_vtab_in_first'>sqlite3_vtab_in_first</a></li>
<li><a href='#sqlite3_vtab_in_first'>sqlite3_vtab_in_next</a></li>
<li><a href='#sqlite3_vtab_nochange'>sqlite3_vtab_nochange</a></li>
<li><a href='#sqlite3_vtab_on_conflict'>sqlite3_vtab_on_conflict</a></li>
<li><a href='#sqlite3_vtab_rhs_value'>sqlite3_vtab_rhs_value</a></li>
<li><a href='#sqlite3_wal_autocheckpoint'>sqlite3_wal_autocheckpoint</a></li>
<li><a href='#sqlite3_wal_checkpoint'>sqlite3_wal_checkpoint</a></li>
<li><a href='#sqlite3_wal_checkpoint_v2'>sqlite3_wal_checkpoint_v2</a></li>
<li><a href='#sqlite3_wal_hook'>sqlite3_wal_hook</a></li>
<li><a href='#sqlite3_win32_set_directory'>sqlite3_win32_set_directory</a></li>
<li><a href='#sqlite3_win32_set_directory'>sqlite3_win32_set_directory16</a></li>
<li><a href='#sqlite3_win32_set_directory'>sqlite3_win32_set_directory8</a></li>
</ul>
</div>
<hr>
<a name="SQLITE_INDEX_SCAN_UNIQUE"></a>
<h2>Virtual Table Scan Flags</h2>
</div>
<blockquote><pre>
#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */
</pre></blockquote>
<p>
Virtual table implementations are allowed to set the
<a href="#sqlite3_index_info">sqlite3_index_info</a>.idxFlags field to some combination of
these bits.
</p><hr><a name="SQLITE_SERIALIZE_NOCOPY"></a>
<h2>Flags for sqlite3_serialize</h2>
</div>
<blockquote><pre>
#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */
</pre></blockquote>
<p>
Zero or more of the following constants can be OR-ed together for
the F argument to <a href="#sqlite3_serialize">sqlite3_serialize(D,S,P,F)</a>.</p>
<p>SQLITE_SERIALIZE_NOCOPY means that <a href="#sqlite3_serialize">sqlite3_serialize()</a> will return
a pointer to contiguous in-memory database that it is currently using,
without making a copy of the database. If SQLite is not currently using
a contiguous in-memory database, then this option causes
<a href="#sqlite3_serialize">sqlite3_serialize()</a> to return a NULL pointer. SQLite will only be
using a contiguous in-memory database if it has been initialized by a
prior call to <a href="#sqlite3_deserialize">sqlite3_deserialize()</a>.
</p><hr><a name="SQLITE_SHM_NLOCK"></a>
<h2>Maximum xShmLock index</h2>
</div>
<blockquote><pre>
#define SQLITE_SHM_NLOCK 8
</pre></blockquote>
<p>
The xShmLock method on <a href="#sqlite3_io_methods">sqlite3_io_methods</a> may use values
between 0 and this upper bound as its "offset" argument.
The SQLite core will never attempt to acquire or release a
lock outside of this range
</p><hr><a name="sqlite3_api_routines"></a>
<h2>Loadable Extension Thunk</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_api_routines sqlite3_api_routines;
</pre></blockquote>
<p>
A pointer to the opaque sqlite3_api_routines structure is passed as
the third parameter to entry points of <a href="loadext.html">loadable extensions</a>. This
structure must be typedefed in order to work around compiler warnings
on some platforms.
</p><hr><a name="sqlite3_backup"></a>
<h2>Online Backup Object</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_backup sqlite3_backup;
</pre></blockquote>
<p>
The sqlite3_backup object records state information about an ongoing
online backup operation. The sqlite3_backup object is created by
a call to <a href="#sqlite3backupinit">sqlite3_backup_init()</a> and is destroyed by a call to
<a href="#sqlite3backupfinish">sqlite3_backup_finish()</a>.</p>
<p>See Also: <a href="backup.html">Using the SQLite Online Backup API</a>
</p><hr><a name="sqlite3_context"></a>
<h2>SQL Function Context Object</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_context sqlite3_context;
</pre></blockquote>
<p>
The context in which an SQL function executes is stored in an
sqlite3_context object. A pointer to an sqlite3_context object
is always first parameter to <a href="appfunc.html">application-defined SQL functions</a>.
The application-defined SQL function implementation will pass this
pointer through into calls to <a href="#sqlite3_result_blob">sqlite3_result()</a>,
<a href="#sqlite3_aggregate_context">sqlite3_aggregate_context()</a>, <a href="#sqlite3_user_data">sqlite3_user_data()</a>,
<a href="#sqlite3_context_db_handle">sqlite3_context_db_handle()</a>, <a href="#sqlite3_get_auxdata">sqlite3_get_auxdata()</a>,
and/or <a href="#sqlite3_get_auxdata">sqlite3_set_auxdata()</a>.
</p><p>26 Methods using this object:
<div class='columns' style='columns: 17em auto;'>
<ul style='padding-top:0;'>
<li><a href='#sqlite3_aggregate_context'>sqlite3_aggregate_context</a></li>
<li><a href='#sqlite3_context_db_handle'>sqlite3_context_db_handle</a></li>
<li><a href='#sqlite3_get_auxdata'>sqlite3_get_auxdata</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_blob</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_blob64</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_double</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_error</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_error16</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_code</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_nomem</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_toobig</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_int</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_int64</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_null</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_pointer</a></li>
<li><a href='#sqlite3_result_subtype'>sqlite3_result_subtype</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_text</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16be</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16le</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_text64</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_value</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_zeroblob</a></li>
<li><a href='#sqlite3_result_blob'>sqlite3_result_zeroblob64</a></li>
<li><a href='#sqlite3_get_auxdata'>sqlite3_set_auxdata</a></li>
<li><a href='#sqlite3_user_data'>sqlite3_user_data</a></li>
</ul>
</div>
</p>
<hr><a name="sqlite3_data_directory"></a>
<h2>Name Of The Folder Holding Database Files</h2>
</div>
<blockquote><pre>
SQLITE_EXTERN char *sqlite3_data_directory;
</pre></blockquote>
<p>
If this global variable is made to point to a string which is
the name of a folder (a.k.a. directory), then all database files
specified with a relative pathname and created or accessed by
SQLite when using a built-in windows <a href="#sqlite3_vfs">VFS</a> will be assumed
to be relative to that directory. If this variable is a NULL
pointer, then SQLite assumes that all database files specified
with a relative pathname are relative to the current directory
for the process. Only the windows VFS makes use of this global
variable; it is ignored by the unix VFS.</p>
<p>Changing the value of this variable while a database connection is
open can result in a corrupt database.</p>
<p>It is not safe to read or modify this variable in more than one
thread at a time. It is not safe to read or modify this variable
if a <a href="#sqlite3">database connection</a> is being used at the same time in a separate
thread.
It is intended that this variable be set once
as part of process initialization and before any SQLite interface
routines have been called and that this variable remain unchanged
thereafter.</p>
<p>The <a href="pragma.html#pragma_data_store_directory">data_store_directory pragma</a> may modify this variable and cause
it to point to memory obtained from <a href="#sqlite3_free">sqlite3_malloc</a>. Furthermore,
the <a href="pragma.html#pragma_data_store_directory">data_store_directory pragma</a> always assumes that any string
that this variable points to is held in memory obtained from
<a href="#sqlite3_free">sqlite3_malloc</a> and the pragma may attempt to free that memory
using <a href="#sqlite3_free">sqlite3_free</a>.
Hence, if this variable is modified directly, either it should be
made NULL or made to point to memory obtained from <a href="#sqlite3_free">sqlite3_malloc</a>
or else the use of the <a href="pragma.html#pragma_data_store_directory">data_store_directory pragma</a> should be avoided.
</p><hr><a name="sqlite3_file"></a>
<h2>OS Interface Open File Handle</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_file sqlite3_file;
struct sqlite3_file {
const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
};
</pre></blockquote>
<p>
An <a href="#sqlite3_file">sqlite3_file</a> object represents an open file in the
<a href="#sqlite3_vfs">OS interface layer</a>. Individual OS interface
implementations will
want to subclass this object by appending additional fields
for their own use. The pMethods entry is a pointer to an
<a href="#sqlite3_io_methods">sqlite3_io_methods</a> object that defines methods for performing
I/O operations on the open file.
</p><hr><a name="sqlite3_filename"></a>
<h2>File Name</h2>
</div>
<blockquote><pre>
typedef const char *sqlite3_filename;
</pre></blockquote>
<p>
Type <a href="#sqlite3_filename">sqlite3_filename</a> is used by SQLite to pass filenames to the
xOpen method of a <a href="vfs.html">VFS</a>. It may be cast to (const char*) and treated
as a normal, nul-terminated, UTF-8 buffer containing the filename, but
may also be passed to special APIs such as:</p>
<p><ul>
<li> sqlite3_filename_database()
<li> sqlite3_filename_journal()
<li> sqlite3_filename_wal()
<li> sqlite3_uri_parameter()
<li> sqlite3_uri_boolean()
<li> sqlite3_uri_int64()
<li> sqlite3_uri_key()
</ul>
</p><hr><a name="sqlite3_index_info"></a>
<h2>Virtual Table Indexing Information</h2>
</div>
<blockquote><pre>
struct sqlite3_index_info {
/* Inputs */
int nConstraint; /* Number of entries in aConstraint */
struct sqlite3_index_constraint {
int iColumn; /* Column constrained. -1 for ROWID */
unsigned char op; /* Constraint operator */
unsigned char usable; /* True if this constraint is usable */
int iTermOffset; /* Used internally - xBestIndex should ignore */
} *aConstraint; /* Table of WHERE clause constraints */
int nOrderBy; /* Number of terms in the ORDER BY clause */
struct sqlite3_index_orderby {
int iColumn; /* Column number */
unsigned char desc; /* True for DESC. False for ASC. */
} *aOrderBy; /* The ORDER BY clause */
/* Outputs */
struct sqlite3_index_constraint_usage {
int argvIndex; /* if >0, constraint is part of argv to xFilter */
unsigned char omit; /* Do not code a test for this constraint */
} *aConstraintUsage;
int idxNum; /* Number used to identify the index */
char *idxStr; /* String, possibly obtained from sqlite3_malloc */
int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
int orderByConsumed; /* True if output is already ordered */
double estimatedCost; /* Estimated cost of using this index */
/* Fields below are only available in SQLite 3.8.2 and later */
sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
/* Fields below are only available in SQLite 3.9.0 and later */
int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
/* Fields below are only available in SQLite 3.10.0 and later */
sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */
};
</pre></blockquote>
<p>
The sqlite3_index_info structure and its substructures is used as part
of the <a href="vtab.html">virtual table</a> interface to
pass information into and receive the reply from the <a href="vtab.html#xbestindex">xBestIndex</a>
method of a <a href="#sqlite3_module">virtual table module</a>. The fields under **Inputs** are the
inputs to xBestIndex and are read-only. xBestIndex inserts its
results into the **Outputs** fields.</p>
<p>The aConstraint[] array records WHERE clause constraints of the form:</p>
<p><blockquote>column OP expr</blockquote></p>
<p>where OP is =, <, <=, >, or >=. The particular operator is
stored in aConstraint[].op using one of the
<a href="#SQLITE_INDEX_CONSTRAINT_EQ">SQLITE_INDEX_CONSTRAINT_ values</a>.
The index of the column is stored in
aConstraint[].iColumn. aConstraint[].usable is TRUE if the
expr on the right-hand side can be evaluated (and thus the constraint
is usable) and false if it cannot.</p>
<p>The optimizer automatically inverts terms of the form "expr OP column"
and makes other simplifications to the WHERE clause in an attempt to
get as many WHERE clause terms into the form shown above as possible.
The aConstraint[] array only reports WHERE clause terms that are
relevant to the particular virtual table being queried.</p>
<p>Information about the ORDER BY clause is stored in aOrderBy[].
Each term of aOrderBy records a column of the ORDER BY clause.</p>
<p>The colUsed field indicates which columns of the virtual table may be
required by the current scan. Virtual table columns are numbered from
zero in the order in which they appear within the CREATE TABLE statement
passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
the corresponding bit is set within the colUsed mask if the column may be
required by SQLite. If the table has at least 64 columns and any column
to the right of the first 63 is required, then bit 63 of colUsed is also
set. In other words, column iCol may be required if the expression
(colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
non-zero.</p>
<p>The <a href="vtab.html#xbestindex">xBestIndex</a> method must fill aConstraintUsage[] with information
about what parameters to pass to xFilter. If argvIndex>0 then
the right-hand side of the corresponding aConstraint[] is evaluated
and becomes the argvIndex-th entry in argv. If aConstraintUsage[].omit
is true, then the constraint is assumed to be fully handled by the
virtual table and might not be checked again by the byte code. The
aConstraintUsage[].omit flag is an optimization hint. When the omit flag
is left in its default setting of false, the constraint will always be
checked separately in byte code. If the omit flag is change to true, then
the constraint may or may not be checked in byte code. In other words,
when the omit flag is true there is no guarantee that the constraint will
not be checked again using byte code.</p>
<p>The idxNum and idxStr values are recorded and passed into the
<a href="vtab.html#xfilter">xFilter</a> method.
<a href="#sqlite3_free">sqlite3_free()</a> is used to free idxStr if and only if
needToFreeIdxStr is true.</p>
<p>The orderByConsumed means that output from <a href="vtab.html#xfilter">xFilter</a>/<a href="vtab.html#xnext">xNext</a> will occur in
the correct order to satisfy the ORDER BY clause so that no separate
sorting step is required.</p>
<p>The estimatedCost value is an estimate of the cost of a particular
strategy. A cost of N indicates that the cost of the strategy is similar
to a linear scan of an SQLite table with N rows. A cost of log(N)
indicates that the expense of the operation is similar to that of a
binary search on a unique indexed field of an SQLite table with N rows.</p>
<p>The estimatedRows value is an estimate of the number of rows that
will be returned by the strategy.</p>
<p>The xBestIndex method may optionally populate the idxFlags field with a
mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
assumes that the strategy may visit at most one row.</p>
<p>Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
SQLite also assumes that if a call to the xUpdate() method is made as
part of the same statement to delete or update a virtual table row and the
implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
any database changes. In other words, if the xUpdate() returns
SQLITE_CONSTRAINT, the database contents must be exactly as they were
before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
the xUpdate method are automatically rolled back by SQLite.</p>
<p>IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
structure for SQLite <a href="releaselog/3_8_2.html">version 3.8.2</a> (2013-12-06).
If a virtual table extension is
used with an SQLite version earlier than 3.8.2, the results of attempting
to read or write the estimatedRows field are undefined (but are likely
to include crashing the application). The estimatedRows field should
therefore only be used if <a href="#sqlite3_libversion">sqlite3_libversion_number()</a> returns a
value greater than or equal to 3008002. Similarly, the idxFlags field
was added for <a href="releaselog/3_9_0.html">version 3.9.0</a> (2015-10-14).
It may therefore only be used if
sqlite3_libversion_number() returns a value greater than or equal to
3009000.
</p><p>3 Methods using this object:
<a href="#sqlite3_vtab_collation">sqlite3_vtab_collation()</a>,
<a href="#sqlite3_vtab_distinct">sqlite3_vtab_distinct()</a>,
<a href="#sqlite3_vtab_rhs_value">sqlite3_vtab_rhs_value()</a></p>
<hr><a name="sqlite3_io_methods"></a>
<h2>OS Interface File Virtual Methods Object</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_io_methods sqlite3_io_methods;
struct sqlite3_io_methods {
int iVersion;
int (*xClose)(sqlite3_file*);
int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
int (*xSync)(sqlite3_file*, int flags);
int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
int (*xLock)(sqlite3_file*, int);
int (*xUnlock)(sqlite3_file*, int);
int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
int (*xFileControl)(sqlite3_file*, int op, void *pArg);
int (*xSectorSize)(sqlite3_file*);
int (*xDeviceCharacteristics)(sqlite3_file*);
/* Methods above are valid for version 1 */
int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
void (*xShmBarrier)(sqlite3_file*);
int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
/* Methods above are valid for version 2 */
int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
/* Methods above are valid for version 3 */
/* Additional methods may be added in future releases */
};
</pre></blockquote>
<p>
Every file opened by the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a> method populates an
<a href="#sqlite3_file">sqlite3_file</a> object (or, more commonly, a subclass of the
<a href="#sqlite3_file">sqlite3_file</a> object) with a pointer to an instance of this object.
This object defines the methods used to perform various operations
against the open file represented by the <a href="#sqlite3_file">sqlite3_file</a> object.</p>
<p>If the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a> method sets the sqlite3_file.pMethods element
to a non-NULL pointer, then the sqlite3_io_methods.xClose method
may be invoked even if the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a> reported that it failed. The
only way to prevent a call to xClose following a failed <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a>
is for the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a> to set the sqlite3_file.pMethods element
to NULL.</p>
<p>The flags argument to xSync may be one of <a href="#SQLITE_SYNC_DATAONLY">SQLITE_SYNC_NORMAL</a> or
<a href="#SQLITE_SYNC_DATAONLY">SQLITE_SYNC_FULL</a>. The first choice is the normal fsync().
The second choice is a Mac OS X style fullsync. The <a href="#SQLITE_SYNC_DATAONLY">SQLITE_SYNC_DATAONLY</a>
flag may be ORed in to indicate that only the data of the file
and not its inode needs to be synced.</p>
<p>The integer values to xLock() and xUnlock() are one of
<ul>
<li> <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_NONE</a>,
<li> <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_SHARED</a>,
<li> <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_RESERVED</a>,
<li> <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_PENDING</a>, or
<li> <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_EXCLUSIVE</a>.
</ul>
xLock() upgrades the database file lock. In other words, xLock() moves the
database file lock in the direction NONE toward EXCLUSIVE. The argument to
xLock() is always one of SHARED, RESERVED, PENDING, or EXCLUSIVE, never
SQLITE_LOCK_NONE. If the database file lock is already at or above the
requested lock, then the call to xLock() is a no-op.
xUnlock() downgrades the database file lock to either SHARED or NONE.
If the lock is already at or below the requested lock state, then the call
to xUnlock() is a no-op.
The xCheckReservedLock() method checks whether any database connection,
either in this process or in some other process, is holding a RESERVED,
PENDING, or EXCLUSIVE lock on the file. It returns true
if such a lock exists and false otherwise.</p>
<p>The xFileControl() method is a generic interface that allows custom
VFS implementations to directly control an open file using the
<a href="#sqlite3_file_control">sqlite3_file_control()</a> interface. The second "op" argument is an
integer opcode. The third argument is a generic pointer intended to
point to a structure that may contain arguments or space in which to
write return values. Potential uses for xFileControl() might be
functions to enable blocking locks with timeouts, to change the
locking strategy (for example to use dot-file locks), to inquire
about the status of a lock, or to break stale locks. The SQLite
core reserves all opcodes less than 100 for its own use.
A <a href="#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE">list of opcodes</a> less than 100 is available.
Applications that define a custom xFileControl method should use opcodes
greater than 100 to avoid conflicts. VFS implementations should
return <a href="#SQLITE_ABORT">SQLITE_NOTFOUND</a> for file control opcodes that they do not
recognize.</p>
<p>The xSectorSize() method returns the sector size of the
device that underlies the file. The sector size is the
minimum write that can be performed without disturbing
other bytes in the file. The xDeviceCharacteristics()
method returns a bit vector describing behaviors of the
underlying device:</p>
<p><ul>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC512</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC1K</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC2K</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC4K</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC8K</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC16K</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC32K</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC64K</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_SAFE_APPEND</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_SEQUENTIAL</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_POWERSAFE_OVERWRITE</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_IMMUTABLE</a>
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_BATCH_ATOMIC</a>
</ul></p>
<p>The SQLITE_IOCAP_ATOMIC property means that all writes of
any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
mean that writes of blocks that are nnn bytes in size and
are aligned to an address which is an integer multiple of
nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
that when data is appended to a file, the data is appended
first then the size of the file is extended, never the other
way around. The SQLITE_IOCAP_SEQUENTIAL property means that
information is written to disk in the same order as calls
to xWrite().</p>
<p>If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
in the unread portions of the buffer with zeros. A VFS that
fails to zero-fill short reads might seem to work. However,
failure to zero-fill short reads will eventually lead to
database corruption.
</p><hr><a name="sqlite3_mem_methods"></a>
<h2>Memory Allocation Routines</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_mem_methods sqlite3_mem_methods;
struct sqlite3_mem_methods {
void *(*xMalloc)(int); /* Memory allocation function */
void (*xFree)(void*); /* Free a prior allocation */
void *(*xRealloc)(void*,int); /* Resize an allocation */
int (*xSize)(void*); /* Return the size of an allocation */
int (*xRoundup)(int); /* Round up request size to allocation size */
int (*xInit)(void*); /* Initialize the memory allocator */
void (*xShutdown)(void*); /* Deinitialize the memory allocator */
void *pAppData; /* Argument to xInit() and xShutdown() */
};
</pre></blockquote>
<p>
An instance of this object defines the interface between SQLite
and low-level memory allocation routines.</p>
<p>This object is used in only one place in the SQLite interface.
A pointer to an instance of this object is the argument to
<a href="#sqlite3_config">sqlite3_config()</a> when the configuration option is
<a href="#sqliteconfigmalloc">SQLITE_CONFIG_MALLOC</a> or <a href="#sqliteconfiggetmalloc">SQLITE_CONFIG_GETMALLOC</a>.
By creating an instance of this object
and passing it to <a href="#sqlite3_config">sqlite3_config</a>(<a href="#sqliteconfigmalloc">SQLITE_CONFIG_MALLOC</a>)
during configuration, an application can specify an alternative
memory allocation subsystem for SQLite to use for all of its
dynamic memory needs.</p>
<p>Note that SQLite comes with several <a href="malloc.html#altalloc">built-in memory allocators</a>
that are perfectly adequate for the overwhelming majority of applications
and that this object is only useful to a tiny minority of applications
with specialized memory allocation requirements. This object is
also used during testing of SQLite in order to specify an alternative
memory allocator that simulates memory out-of-memory conditions in
order to verify that SQLite recovers gracefully from such
conditions.</p>
<p>The xMalloc, xRealloc, and xFree methods must work like the
malloc(), realloc() and free() functions from the standard C library.
SQLite guarantees that the second argument to
xRealloc is always a value returned by a prior call to xRoundup.</p>
<p>xSize should return the allocated size of a memory allocation
previously obtained from xMalloc or xRealloc. The allocated size
is always at least as big as the requested size but may be larger.</p>
<p>The xRoundup method returns what would be the allocated size of
a memory allocation given a particular requested size. Most memory
allocators round up memory allocations at least to the next multiple
of 8. Some allocators round up to a larger multiple or to a power of 2.
Every memory allocation request coming in through <a href="#sqlite3_free">sqlite3_malloc()</a>
or <a href="#sqlite3_free">sqlite3_realloc()</a> first calls xRoundup. If xRoundup returns 0,
that causes the corresponding memory allocation to fail.</p>
<p>The xInit method initializes the memory allocator. For example,
it might allocate any required mutexes or initialize internal data
structures. The xShutdown method is invoked (indirectly) by
<a href="#sqlite3_initialize">sqlite3_shutdown()</a> and should deallocate any resources acquired
by xInit. The pAppData pointer is used as the only parameter to
xInit and xShutdown.</p>
<p>SQLite holds the <a href="#SQLITE_MUTEX_FAST">SQLITE_MUTEX_STATIC_MAIN</a> mutex when it invokes
the xInit method, so the xInit method need not be threadsafe. The
xShutdown method is only called from <a href="#sqlite3_initialize">sqlite3_shutdown()</a> so it does
not need to be threadsafe either. For all other methods, SQLite
holds the <a href="#SQLITE_MUTEX_FAST">SQLITE_MUTEX_STATIC_MEM</a> mutex as long as the
<a href="#sqliteconfigmemstatus">SQLITE_CONFIG_MEMSTATUS</a> configuration option is turned on (which
it is by default) and so the methods are automatically serialized.
However, if <a href="#sqliteconfigmemstatus">SQLITE_CONFIG_MEMSTATUS</a> is disabled, then the other
methods must be threadsafe or else make their own arrangements for
serialization.</p>
<p>SQLite will never invoke xInit() more than once without an intervening
call to xShutdown().
</p><hr><a name="sqlite3_mutex"></a>
<h2>Mutex Handle</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_mutex sqlite3_mutex;
</pre></blockquote>
<p>
The mutex module within SQLite defines <a href="#sqlite3_mutex">sqlite3_mutex</a> to be an
abstract type for a mutex object. The SQLite core never looks
at the internal representation of an <a href="#sqlite3_mutex">sqlite3_mutex</a>. It only
deals with pointers to the <a href="#sqlite3_mutex">sqlite3_mutex</a> object.</p>
<p>Mutexes are created using <a href="#sqlite3_mutex_alloc">sqlite3_mutex_alloc()</a>.
</p><hr><a name="sqlite3_mutex_methods"></a>
<h2>Mutex Methods Object</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
struct sqlite3_mutex_methods {
int (*xMutexInit)(void);
int (*xMutexEnd)(void);
sqlite3_mutex *(*xMutexAlloc)(int);
void (*xMutexFree)(sqlite3_mutex *);
void (*xMutexEnter)(sqlite3_mutex *);
int (*xMutexTry)(sqlite3_mutex *);
void (*xMutexLeave)(sqlite3_mutex *);
int (*xMutexHeld)(sqlite3_mutex *);
int (*xMutexNotheld)(sqlite3_mutex *);
};
</pre></blockquote>
<p>
An instance of this structure defines the low-level routines
used to allocate and use mutexes.</p>
<p>Usually, the default mutex implementations provided by SQLite are
sufficient, however the application has the option of substituting a custom
implementation for specialized deployments or systems for which SQLite
does not provide a suitable implementation. In this case, the application
creates and populates an instance of this structure to pass
to sqlite3_config() along with the <a href="#sqliteconfigmutex">SQLITE_CONFIG_MUTEX</a> option.
Additionally, an instance of this structure can be used as an
output variable when querying the system for the current mutex
implementation, using the <a href="#sqliteconfiggetmutex">SQLITE_CONFIG_GETMUTEX</a> option.</p>
<p>The xMutexInit method defined by this structure is invoked as
part of system initialization by the sqlite3_initialize() function.
The xMutexInit routine is called by SQLite exactly once for each
effective call to <a href="#sqlite3_initialize">sqlite3_initialize()</a>.</p>
<p>The xMutexEnd method defined by this structure is invoked as
part of system shutdown by the sqlite3_shutdown() function. The
implementation of this method is expected to release all outstanding
resources obtained by the mutex methods implementation, especially
those obtained by the xMutexInit method. The xMutexEnd()
interface is invoked exactly once for each call to <a href="#sqlite3_initialize">sqlite3_shutdown()</a>.</p>
<p>The remaining seven methods defined by this structure (xMutexAlloc,
xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
xMutexNotheld) implement the following interfaces (respectively):</p>
<p><ul>
<li> <a href="#sqlite3_mutex_alloc">sqlite3_mutex_alloc()</a> </li>
<li> <a href="#sqlite3_mutex_alloc">sqlite3_mutex_free()</a> </li>
<li> <a href="#sqlite3_mutex_alloc">sqlite3_mutex_enter()</a> </li>
<li> <a href="#sqlite3_mutex_alloc">sqlite3_mutex_try()</a> </li>
<li> <a href="#sqlite3_mutex_alloc">sqlite3_mutex_leave()</a> </li>
<li> <a href="#sqlite3_mutex_held">sqlite3_mutex_held()</a> </li>
<li> <a href="#sqlite3_mutex_held">sqlite3_mutex_notheld()</a> </li>
</ul></p>
<p>The only difference is that the public sqlite3_XXX functions enumerated
above silently ignore any invocations that pass a NULL pointer instead
of a valid mutex handle. The implementations of the methods defined
by this structure are not required to handle this case. The results
of passing a NULL pointer instead of a valid mutex handle are undefined
(i.e. it is acceptable to provide an implementation that segfaults if
it is passed a NULL pointer).</p>
<p>The xMutexInit() method must be threadsafe. It must be harmless to
invoke xMutexInit() multiple times within the same process and without
intervening calls to xMutexEnd(). Second and subsequent calls to
xMutexInit() must be no-ops.</p>
<p>xMutexInit() must not use SQLite memory allocation (<a href="#sqlite3_free">sqlite3_malloc()</a>
and its associates). Similarly, xMutexAlloc() must not use SQLite memory
allocation for a static mutex. However xMutexAlloc() may use SQLite
memory allocation for a fast or recursive mutex.</p>
<p>SQLite will invoke the xMutexEnd() method when <a href="#sqlite3_initialize">sqlite3_shutdown()</a> is
called, but only if the prior call to xMutexInit returned SQLITE_OK.
If xMutexInit fails in any way, it is expected to clean up after itself
prior to returning.
</p><hr><a name="sqlite3_pcache"></a>
<h2>Custom Page Cache Object</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_pcache sqlite3_pcache;
</pre></blockquote>
<p>
The sqlite3_pcache type is opaque. It is implemented by
the pluggable module. The SQLite core has no knowledge of
its size or internal structure and never deals with the
sqlite3_pcache object except by holding and passing pointers
to the object.</p>
<p>See <a href="#sqlite3_pcache_methods2">sqlite3_pcache_methods2</a> for additional information.
</p><hr><a name="sqlite3_pcache_page"></a>
<h2>Custom Page Cache Object</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_pcache_page sqlite3_pcache_page;
struct sqlite3_pcache_page {
void *pBuf; /* The content of the page */
void *pExtra; /* Extra information associated with the page */
};
</pre></blockquote>
<p>
The sqlite3_pcache_page object represents a single page in the
page cache. The page cache will allocate instances of this
object. Various methods of the page cache use pointers to instances
of this object as parameters or as their return value.</p>
<p>See <a href="#sqlite3_pcache_methods2">sqlite3_pcache_methods2</a> for additional information.
</p><hr><a name="sqlite3_temp_directory"></a>
<h2>Name Of The Folder Holding Temporary Files</h2>
</div>
<blockquote><pre>
SQLITE_EXTERN char *sqlite3_temp_directory;
</pre></blockquote>
<p>
If this global variable is made to point to a string which is
the name of a folder (a.k.a. directory), then all temporary files
created by SQLite when using a built-in <a href="#sqlite3_vfs">VFS</a>
will be placed in that directory. If this variable
is a NULL pointer, then SQLite performs a search for an appropriate
temporary file directory.</p>
<p>Applications are strongly discouraged from using this global variable.
It is required to set a temporary folder on Windows Runtime (WinRT).
But for all other platforms, it is highly recommended that applications
neither read nor write this variable. This global variable is a relic
that exists for backwards compatibility of legacy applications and should
be avoided in new projects.</p>
<p>It is not safe to read or modify this variable in more than one
thread at a time. It is not safe to read or modify this variable
if a <a href="#sqlite3">database connection</a> is being used at the same time in a separate
thread.
It is intended that this variable be set once
as part of process initialization and before any SQLite interface
routines have been called and that this variable remain unchanged
thereafter.</p>
<p>The <a href="pragma.html#pragma_temp_store_directory">temp_store_directory pragma</a> may modify this variable and cause
it to point to memory obtained from <a href="#sqlite3_free">sqlite3_malloc</a>. Furthermore,
the <a href="pragma.html#pragma_temp_store_directory">temp_store_directory pragma</a> always assumes that any string
that this variable points to is held in memory obtained from
<a href="#sqlite3_free">sqlite3_malloc</a> and the pragma may attempt to free that memory
using <a href="#sqlite3_free">sqlite3_free</a>.
Hence, if this variable is modified directly, either it should be
made NULL or made to point to memory obtained from <a href="#sqlite3_free">sqlite3_malloc</a>
or else the use of the <a href="pragma.html#pragma_temp_store_directory">temp_store_directory pragma</a> should be avoided.
Except when requested by the <a href="pragma.html#pragma_temp_store_directory">temp_store_directory pragma</a>, SQLite
does not free the memory that sqlite3_temp_directory points to. If
the application wants that memory to be freed, it must do
so itself, taking care to only do so after all <a href="#sqlite3">database connection</a>
objects have been destroyed.</p>
<p><b>Note to Windows Runtime users:</b> The temporary directory must be set
prior to calling <a href="#sqlite3_open">sqlite3_open</a> or <a href="#sqlite3_open">sqlite3_open_v2</a>. Otherwise, various
features that require the use of temporary files may fail. Here is an
example of how to do this using C++ with the Windows Runtime:</p>
<p><blockquote><pre>
LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
TemporaryFolder->Path->Data();
char zPathBuf[MAX_PATH + 1];
memset(zPathBuf, 0, sizeof(zPathBuf));
WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
NULL, NULL);
sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
</pre></blockquote>
</p><hr><a name="sqlite3_vfs"></a>
<h2>OS Interface Object</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_vfs sqlite3_vfs;
typedef void (*sqlite3_syscall_ptr)(void);
struct sqlite3_vfs {
int iVersion; /* Structure version number (currently 3) */
int szOsFile; /* Size of subclassed sqlite3_file */
int mxPathname; /* Maximum file pathname length */
sqlite3_vfs *pNext; /* Next registered VFS */
const char *zName; /* Name of this virtual file system */
void *pAppData; /* Pointer to application-specific data */
int (*xOpen)(sqlite3_vfs*, sqlite3_filename zName, sqlite3_file*,
int flags, int *pOutFlags);
int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
void (*xDlClose)(sqlite3_vfs*, void*);
int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
int (*xSleep)(sqlite3_vfs*, int microseconds);
int (*xCurrentTime)(sqlite3_vfs*, double*);
int (*xGetLastError)(sqlite3_vfs*, int, char *);
/*
** The methods above are in version 1 of the sqlite_vfs object
** definition. Those that follow are added in version 2 or later
*/
int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
/*
** The methods above are in versions 1 and 2 of the sqlite_vfs object.
** Those below are for version 3 and greater.
*/
int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
/*
** The methods above are in versions 1 through 3 of the sqlite_vfs object.
** New fields may be appended in future versions. The iVersion
** value will increment whenever this happens.
*/
};
</pre></blockquote>
<p>
An instance of the sqlite3_vfs object defines the interface between
the SQLite core and the underlying operating system. The "vfs"
in the name of the object stands for "virtual file system". See
the <a href="vfs.html">VFS documentation</a> for further information.</p>
<p>The VFS interface is sometimes extended by adding new methods onto
the end. Each time such an extension occurs, the iVersion field
is incremented. The iVersion value started out as 1 in
SQLite <a href="releaselog/3_5_0.html">version 3.5.0</a> on 2007-09-04, then increased to 2
with SQLite <a href="releaselog/3_7_0.html">version 3.7.0</a> on 2010-07-21, and then increased
to 3 with SQLite <a href="releaselog/3_7_6.html">version 3.7.6</a> on 2011-04-12. Additional fields
may be appended to the sqlite3_vfs object and the iVersion value
may increase again in future versions of SQLite.
Note that due to an oversight, the structure
of the sqlite3_vfs object changed in the transition from
SQLite <a href="releaselog/3_5_9.html">version 3.5.9</a> to <a href="releaselog/3_6_0.html">version 3.6.0</a> on 2008-07-16
and yet the iVersion field was not increased.</p>
<p>The szOsFile field is the size of the subclassed <a href="#sqlite3_file">sqlite3_file</a>
structure used by this VFS. mxPathname is the maximum length of
a pathname in this VFS.</p>
<p>Registered sqlite3_vfs objects are kept on a linked list formed by
the pNext pointer. The <a href="#sqlite3_vfs_find">sqlite3_vfs_register()</a>
and <a href="#sqlite3_vfs_find">sqlite3_vfs_unregister()</a> interfaces manage this list
in a thread-safe way. The <a href="#sqlite3_vfs_find">sqlite3_vfs_find()</a> interface
searches the list. Neither the application code nor the VFS
implementation should use the pNext pointer.</p>
<p>The pNext field is the only field in the sqlite3_vfs
structure that SQLite will ever modify. SQLite will only access
or modify this field while holding a particular static mutex.
The application should never modify anything within the sqlite3_vfs
object once the object has been registered.</p>
<p>The zName field holds the name of the VFS module. The name must
be unique across all VFS modules.</p>
<p><a name="sqlite3vfsxopen"></a>
SQLite guarantees that the zFilename parameter to xOpen
is either a NULL pointer or string obtained
from xFullPathname() with an optional suffix added.
If a suffix is added to the zFilename parameter, it will
consist of a single "-" character followed by no more than
11 alphanumeric and/or "-" characters.
SQLite further guarantees that
the string will be valid and unchanged until xClose() is
called. Because of the previous sentence,
the <a href="#sqlite3_file">sqlite3_file</a> can safely store a pointer to the
filename if it needs to remember the filename for some reason.
If the zFilename parameter to xOpen is a NULL pointer then xOpen
must invent its own temporary name for the file. Whenever the
xFilename parameter is NULL it will also be the case that the
flags parameter will include <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_DELETEONCLOSE</a>.</p>
<p>The flags argument to xOpen() includes all bits set in
the flags argument to <a href="#sqlite3_open">sqlite3_open_v2()</a>. Or if <a href="#sqlite3_open">sqlite3_open()</a>
or <a href="#sqlite3_open">sqlite3_open16()</a> is used, then flags includes at least
<a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READWRITE</a> | <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_CREATE</a>.
If xOpen() opens a file read-only then it sets *pOutFlags to
include <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READONLY</a>. Other bits in *pOutFlags may be set.</p>
<p>SQLite will also add one of the following flags to the xOpen()
call, depending on the object being opened:</p>
<p><ul>
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_MAIN_DB</a>
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_MAIN_JOURNAL</a>
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_TEMP_DB</a>
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_TEMP_JOURNAL</a>
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_TRANSIENT_DB</a>
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_SUBJOURNAL</a>
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_SUPER_JOURNAL</a>
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_WAL</a>
</ul></p>
<p>The file I/O implementation can use the object type flags to
change the way it deals with files. For example, an application
that does not care about crash recovery or rollback might make
the open of a journal file a no-op. Writes to this journal would
also be no-ops, and any attempt to read the journal would return
SQLITE_IOERR. Or the implementation might recognize that a database
file will be doing page-aligned sector reads and writes in a random
order and set up its I/O subsystem accordingly.</p>
<p>SQLite might also add one of the following flags to the xOpen method:</p>
<p><ul>
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_DELETEONCLOSE</a>
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_EXCLUSIVE</a>
</ul></p>
<p>The <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_DELETEONCLOSE</a> flag means the file should be
deleted when it is closed. The <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_DELETEONCLOSE</a>
will be set for TEMP databases and their journals, transient
databases, and subjournals.</p>
<p>The <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_EXCLUSIVE</a> flag is always used in conjunction
with the <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_CREATE</a> flag, which are both directly
analogous to the O_EXCL and O_CREAT flags of the POSIX open()
API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
SQLITE_OPEN_CREATE, is used to indicate that file should always
be created, and that it is an error if it already exists.
It is <i>not</i> used to indicate the file should be opened
for exclusive access.</p>
<p>At least szOsFile bytes of memory are allocated by SQLite
to hold the <a href="#sqlite3_file">sqlite3_file</a> structure passed as the third
argument to xOpen. The xOpen method does not have to
allocate the structure; it should just fill it in. Note that
the xOpen method must set the sqlite3_file.pMethods to either
a valid <a href="#sqlite3_io_methods">sqlite3_io_methods</a> object or to NULL. xOpen must do
this even if the open fails. SQLite expects that the sqlite3_file.pMethods
element will be valid after xOpen returns regardless of the success
or failure of the xOpen call.</p>
<p><a name="sqlite3vfsxaccess"></a>
The flags argument to xAccess() may be <a href="#SQLITE_ACCESS_EXISTS">SQLITE_ACCESS_EXISTS</a>
to test for the existence of a file, or <a href="#SQLITE_ACCESS_EXISTS">SQLITE_ACCESS_READWRITE</a> to
test whether a file is readable and writable, or <a href="#SQLITE_ACCESS_EXISTS">SQLITE_ACCESS_READ</a>
to test whether a file is at least readable. The SQLITE_ACCESS_READ
flag is never actually used and is not implemented in the built-in
VFSes of SQLite. The file is named by the second argument and can be a
directory. The xAccess method returns <a href="#SQLITE_ABORT">SQLITE_OK</a> on success or some
non-zero error code if there is an I/O error or if the name of
the file given in the second argument is illegal. If SQLITE_OK
is returned, then non-zero or zero is written into *pResOut to indicate
whether or not the file is accessible.</p>
<p>SQLite will always allocate at least mxPathname+1 bytes for the
output buffer xFullPathname. The exact size of the output buffer
is also passed as a parameter to both methods. If the output buffer
is not large enough, <a href="#SQLITE_ABORT">SQLITE_CANTOPEN</a> should be returned. Since this is
handled as a fatal error by SQLite, vfs implementations should endeavor
to prevent this by setting mxPathname to a sufficiently large value.</p>
<p>The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
interfaces are not strictly a part of the filesystem, but they are
included in the VFS structure for completeness.
The xRandomness() function attempts to return nBytes bytes
of good-quality randomness into zOut. The return value is
the actual number of bytes of randomness obtained.
The xSleep() method causes the calling thread to sleep for at
least the number of microseconds given. The xCurrentTime()
method returns a Julian Day Number for the current date and time as
a floating point value.
The xCurrentTimeInt64() method returns, as an integer, the Julian
Day Number multiplied by 86400000 (the number of milliseconds in
a 24-hour day).
SQLite will use the xCurrentTimeInt64() method to get the current
date and time if that method is available (if iVersion is 2 or
greater and the function pointer is not NULL) and will fall back
to xCurrentTime() if xCurrentTimeInt64() is unavailable.</p>
<p>The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
are not used by the SQLite core. These optional interfaces are provided
by some VFSes to facilitate testing of the VFS code. By overriding
system calls with functions under its control, a test program can
simulate faults and error conditions that would otherwise be difficult
or impossible to induce. The set of system calls that can be overridden
varies from one VFS to another, and from one version of the same VFS to the
next. Applications that use these interfaces must be prepared for any
or all of these interfaces to be NULL or for their behavior to change
from one release to the next. Applications must not attempt to access
any of these methods if the iVersion of the VFS is less than 3.
</p><hr><a name="sqlite3_vtab"></a>
<h2>Virtual Table Instance Object</h2>
</div>
<blockquote><pre>
struct sqlite3_vtab {
const sqlite3_module *pModule; /* The module for this virtual table */
int nRef; /* Number of open cursors */
char *zErrMsg; /* Error message from sqlite3_mprintf() */
/* Virtual table implementations will typically add additional fields */
};
</pre></blockquote>
<p>
Every <a href="#sqlite3_module">virtual table module</a> implementation uses a subclass
of this object to describe a particular instance
of the <a href="vtab.html">virtual table</a>. Each subclass will
be tailored to the specific needs of the module implementation.
The purpose of this superclass is to define certain fields that are
common to all module implementations.</p>
<p>Virtual tables methods can set an error message by assigning a
string obtained from <a href="#sqlite3_mprintf">sqlite3_mprintf()</a> to zErrMsg. The method should
take care that any prior string is freed by a call to <a href="#sqlite3_free">sqlite3_free()</a>
prior to assigning a new string to zErrMsg. After the error message
is delivered up to the client application, the string will be automatically
freed by sqlite3_free() and the zErrMsg field will be zeroed.
</p><hr><a name="sqlite3_aggregate_context"></a>
<h2>Obtain Aggregate Function Context</h2>
</div>
<blockquote><pre>
void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
</pre></blockquote>
<p>
Implementations of aggregate SQL functions use this
routine to allocate memory for storing their state.</p>
<p>The first time the sqlite3_aggregate_context(C,N) routine is called
for a particular aggregate function, SQLite allocates
N bytes of memory, zeroes out that memory, and returns a pointer
to the new memory. On second and subsequent calls to
sqlite3_aggregate_context() for the same aggregate function instance,
the same buffer is returned. Sqlite3_aggregate_context() is normally
called once for each invocation of the xStep callback and then one
last time when the xFinal callback is invoked. When no rows match
an aggregate query, the xStep() callback of the aggregate function
implementation is never called and xFinal() is called exactly once.
In those cases, sqlite3_aggregate_context() might be called for the
first time from within xFinal().</p>
<p>The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
when first called if N is less than or equal to zero or if a memory
allocation error occurs.</p>
<p>The amount of space allocated by sqlite3_aggregate_context(C,N) is
determined by the N parameter on first successful call. Changing the
value of N in any subsequent call to sqlite3_aggregate_context() within
the same aggregate function instance will not resize the memory
allocation. Within the xFinal callback, it is customary to set
N=0 in calls to sqlite3_aggregate_context(C,N) so that no
pointless memory allocations occur.</p>
<p>SQLite automatically frees the memory allocated by
sqlite3_aggregate_context() when the aggregate query concludes.</p>
<p>The first parameter must be a copy of the
<a href="#sqlite3_context">SQL function context</a> that is the first parameter
to the xStep or xFinal callback routine that implements the aggregate
function.</p>
<p>This routine must be called from the same thread in which
the aggregate SQL function is running.
</p><hr><a name="sqlite3_auto_extension"></a>
<h2>Automatically Load Statically Linked Extensions</h2>
</div>
<blockquote><pre>
int sqlite3_auto_extension(void(*xEntryPoint)(void));
</pre></blockquote>
<p>
This interface causes the xEntryPoint() function to be invoked for
each new <a href="#sqlite3">database connection</a> that is created. The idea here is that
xEntryPoint() is the entry point for a statically linked <a href="loadext.html">SQLite extension</a>
that is to be automatically loaded into all new database connections.</p>
<p>Even though the function prototype shows that xEntryPoint() takes
no arguments and returns void, SQLite invokes xEntryPoint() with three
arguments and expects an integer result as if the signature of the
entry point where as follows:</p>
<p><blockquote><pre>
int xEntryPoint(
sqlite3 *db,
const char **pzErrMsg,
const struct sqlite3_api_routines *pThunk
);
</pre></blockquote></p>
<p>If the xEntryPoint routine encounters an error, it should make *pzErrMsg
point to an appropriate error message (obtained from <a href="#sqlite3_mprintf">sqlite3_mprintf()</a>)
and return an appropriate <a href="rescode.html">error code</a>. SQLite ensures that *pzErrMsg
is NULL before calling the xEntryPoint(). SQLite will invoke
<a href="#sqlite3_free">sqlite3_free()</a> on *pzErrMsg after xEntryPoint() returns. If any
xEntryPoint() returns an error, the <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open16()</a>,
or <a href="#sqlite3_open">sqlite3_open_v2()</a> call that provoked the xEntryPoint() will fail.</p>
<p>Calling sqlite3_auto_extension(X) with an entry point X that is already
on the list of automatic extensions is a harmless no-op. No entry point
will be called more than once for each database connection that is opened.</p>
<p>See also: <a href="#sqlite3_reset_auto_extension">sqlite3_reset_auto_extension()</a>
and <a href="#sqlite3_cancel_auto_extension">sqlite3_cancel_auto_extension()</a>
</p><hr><a name="sqlite3_autovacuum_pages"></a>
<h2>Autovacuum Compaction Amount Callback</h2>
</div>
<blockquote><pre>
int sqlite3_autovacuum_pages(
sqlite3 *db,
unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
void*,
void(*)(void*)
);
</pre></blockquote>
<p>
The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback
function C that is invoked prior to each autovacuum of the database
file. The callback is passed a copy of the generic data pointer (P),
the schema-name of the attached database that is being autovacuumed,
the size of the database file in pages, the number of free pages,
and the number of bytes per page, respectively. The callback should
return the number of free pages that should be removed by the
autovacuum. If the callback returns zero, then no autovacuum happens.
If the value returned is greater than or equal to the number of
free pages, then a complete autovacuum happens.</p>
<p><p>If there are multiple ATTACH-ed database files that are being
modified as part of a transaction commit, then the autovacuum pages
callback is invoked separately for each file.</p>
<p><p><b>The callback is not reentrant.</b> The callback function should
not attempt to invoke any other SQLite interface. If it does, bad
things may happen, including segmentation faults and corrupt database
files. The callback function should be a simple function that
does some arithmetic on its input parameters and returns a result.</p>
<p>The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
destructor for the P parameter. If X is not NULL, then X(P) is
invoked whenever the database connection closes or when the callback
is overwritten by another invocation of sqlite3_autovacuum_pages().</p>
<p><p>There is only one autovacuum pages callback per database connection.
Each call to the sqlite3_autovacuum_pages() interface overrides all
previous invocations for that database connection. If the callback
argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
then the autovacuum steps callback is canceled. The return value
from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
be some other error code if something goes wrong. The current
implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
return codes might be added in future releases.</p>
<p><p>If no autovacuum pages callback is specified (the usual case) or
a NULL pointer is provided for the callback,
then the default behavior is to vacuum all free pages. So, in other
words, the default behavior is the same as if the callback function
were something like this:</p>
<p><blockquote><pre>
unsigned int demonstration_autovac_pages_callback(
void *pClientData,
const char *zSchema,
unsigned int nDbPage,
unsigned int nFreePage,
unsigned int nBytePerPage
){
return nFreePage;
}
</pre></blockquote>
</p><hr><a name="sqlite3_bind_parameter_count"></a>
<h2>Number Of SQL Parameters</h2>
</div>
<blockquote><pre>
int sqlite3_bind_parameter_count(sqlite3_stmt*);
</pre></blockquote>
<p>
This routine can be used to find the number of <a href="#sqlite3_bind_blob">SQL parameters</a>
in a <a href="#sqlite3_stmt">prepared statement</a>. SQL parameters are tokens of the
form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
placeholders for values that are <a href="#sqlite3_bind_blob">bound</a>
to the parameters at a later time.</p>
<p>This routine actually returns the index of the largest (rightmost)
parameter. For all forms except ?NNN, this will correspond to the
number of unique parameters. If parameters of the ?NNN form are used,
there may be gaps in the list.</p>
<p>See also: <a href="#sqlite3_bind_blob">sqlite3_bind()</a>,
<a href="#sqlite3_bind_parameter_name">sqlite3_bind_parameter_name()</a>, and
<a href="#sqlite3_bind_parameter_index">sqlite3_bind_parameter_index()</a>.
</p><hr><a name="sqlite3_bind_parameter_index"></a>
<h2>Index Of A Parameter With A Given Name</h2>
</div>
<blockquote><pre>
int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
</pre></blockquote>
<p>
Return the index of an SQL parameter given its name. The
index value returned is suitable for use as the second
parameter to <a href="#sqlite3_bind_blob">sqlite3_bind()</a>. A zero
is returned if no matching parameter is found. The parameter
name must be given in UTF-8 even if the original statement
was prepared from UTF-16 text using <a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a> or
<a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a>.</p>
<p>See also: <a href="#sqlite3_bind_blob">sqlite3_bind()</a>,
<a href="#sqlite3_bind_parameter_count">sqlite3_bind_parameter_count()</a>, and
<a href="#sqlite3_bind_parameter_name">sqlite3_bind_parameter_name()</a>.
</p><hr><a name="sqlite3_bind_parameter_name"></a>
<h2>Name Of A Host Parameter</h2>
</div>
<blockquote><pre>
const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
</pre></blockquote>
<p>
The sqlite3_bind_parameter_name(P,N) interface returns
the name of the N-th <a href="#sqlite3_bind_blob">SQL parameter</a> in the <a href="#sqlite3_stmt">prepared statement</a> P.
SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
respectively.
In other words, the initial ":" or "$" or "@" or "?"
is included as part of the name.
Parameters of the form "?" without a following integer have no name
and are referred to as "nameless" or "anonymous parameters".</p>
<p>The first host parameter has an index of 1, not 0.</p>
<p>If the value N is out of range or if the N-th parameter is
nameless, then NULL is returned. The returned string is
always in UTF-8 encoding even if the named parameter was
originally specified as UTF-16 in <a href="#sqlite3_prepare">sqlite3_prepare16()</a>,
<a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a>, or <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a>.</p>
<p>See also: <a href="#sqlite3_bind_blob">sqlite3_bind()</a>,
<a href="#sqlite3_bind_parameter_count">sqlite3_bind_parameter_count()</a>, and
<a href="#sqlite3_bind_parameter_index">sqlite3_bind_parameter_index()</a>.
</p><hr><a name="sqlite3_blob_bytes"></a>
<h2>Return The Size Of An Open BLOB</h2>
</div>
<blockquote><pre>
int sqlite3_blob_bytes(sqlite3_blob *);
</pre></blockquote>
<p>
Returns the size in bytes of the BLOB accessible via the
successfully opened <a href="#sqlite3_blob">BLOB handle</a> in its only argument. The
incremental blob I/O routines can only read or overwriting existing
blob content; they cannot change the size of a blob.</p>
<p>This routine only works on a <a href="#sqlite3_blob">BLOB handle</a> which has been created
by a prior successful call to <a href="#sqlite3_blob_open">sqlite3_blob_open()</a> and which has not
been closed by <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>. Passing any other pointer in
to this routine results in undefined and probably undesirable behavior.
</p><hr><a name="sqlite3_blob_close"></a>
<h2>Close A BLOB Handle</h2>
</div>
<blockquote><pre>
int sqlite3_blob_close(sqlite3_blob *);
</pre></blockquote>
<p>
This function closes an open <a href="#sqlite3_blob">BLOB handle</a>. The BLOB handle is closed
unconditionally. Even if this routine returns an error code, the
handle is still closed.</p>
<p>If the blob handle being closed was opened for read-write access, and if
the database is in auto-commit mode and there are no other open read-write
blob handles or active write statements, the current transaction is
committed. If an error occurs while committing the transaction, an error
code is returned and the transaction rolled back.</p>
<p>Calling this function with an argument that is not a NULL pointer or an
open blob handle results in undefined behavior. Calling this routine
with a null pointer (such as would be returned by a failed call to
<a href="#sqlite3_blob_open">sqlite3_blob_open()</a>) is a harmless no-op. Otherwise, if this function
is passed a valid open blob handle, the values returned by the
sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
</p><hr><a name="sqlite3_blob_open"></a>
<h2>Open A BLOB For Incremental I/O</h2>
</div>
<blockquote><pre>
int sqlite3_blob_open(
sqlite3*,
const char *zDb,
const char *zTable,
const char *zColumn,
sqlite3_int64 iRow,
int flags,
sqlite3_blob **ppBlob
);
</pre></blockquote>
<p>
This interfaces opens a <a href="#sqlite3_blob">handle</a> to the BLOB located
in row iRow, column zColumn, table zTable in database zDb;
in other words, the same BLOB that would be selected by:</p>
<p><pre>
SELECT zColumn FROM zDb.zTable WHERE <a href="lang_createtable.html#rowid">rowid</a> = iRow;
</pre></p>
<p>Parameter zDb is not the filename that contains the database, but
rather the symbolic name of the database. For attached databases, this is
the name that appears after the AS keyword in the <a href="lang_attach.html">ATTACH</a> statement.
For the main database file, the database name is "main". For TEMP
tables, the database name is "temp".</p>
<p>If the flags parameter is non-zero, then the BLOB is opened for read
and write access. If the flags parameter is zero, the BLOB is opened for
read-only access.</p>
<p>On success, <a href="#SQLITE_ABORT">SQLITE_OK</a> is returned and the new <a href="#sqlite3_blob">BLOB handle</a> is stored
in *ppBlob. Otherwise an <a href="rescode.html">error code</a> is returned and, unless the error
code is SQLITE_MISUSE, *ppBlob is set to NULL. This means that, provided
the API is not misused, it is always safe to call <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>
on *ppBlob after this function it returns.</p>
<p>This function fails with SQLITE_ERROR if any of the following are true:
<ul>
<li> Database zDb does not exist,
<li> Table zTable does not exist within database zDb,
<li> Table zTable is a WITHOUT ROWID table,
<li> Column zColumn does not exist,
<li> Row iRow is not present in the table,
<li> The specified column of row iRow contains a value that is not
a TEXT or BLOB value,
<li> Column zColumn is part of an index, PRIMARY KEY or UNIQUE
constraint and the blob is being opened for read/write access,
<li> <a href="foreignkeys.html">Foreign key constraints</a> are enabled,
column zColumn is part of a <a href="foreignkeys.html#parentchild">child key</a> definition and the blob is
being opened for read/write access.
</ul></p>
<p>Unless it returns SQLITE_MISUSE, this function sets the
<a href="#sqlite3">database connection</a> error code and message accessible via
<a href="#sqlite3_errcode">sqlite3_errcode()</a> and <a href="#sqlite3_errcode">sqlite3_errmsg()</a> and related functions.</p>
<p>A BLOB referenced by sqlite3_blob_open() may be read using the
<a href="#sqlite3_blob_read">sqlite3_blob_read()</a> interface and modified by using
<a href="#sqlite3_blob_write">sqlite3_blob_write()</a>. The <a href="#sqlite3_blob">BLOB handle</a> can be moved to a
different row of the same table using the <a href="#sqlite3_blob_reopen">sqlite3_blob_reopen()</a>
interface. However, the column, table, or database of a <a href="#sqlite3_blob">BLOB handle</a>
cannot be changed after the <a href="#sqlite3_blob">BLOB handle</a> is opened.</p>
<p>If the row that a BLOB handle points to is modified by an
<a href="lang_update.html">UPDATE</a>, <a href="lang_delete.html">DELETE</a>, or by <a href="lang_conflict.html">ON CONFLICT</a> side-effects
then the BLOB handle is marked as "expired".
This is true if any column of the row is changed, even a column
other than the one the BLOB handle is open on.
Calls to <a href="#sqlite3_blob_read">sqlite3_blob_read()</a> and <a href="#sqlite3_blob_write">sqlite3_blob_write()</a> for
an expired BLOB handle fail with a return code of <a href="#SQLITE_ABORT">SQLITE_ABORT</a>.
Changes written into a BLOB prior to the BLOB expiring are not
rolled back by the expiration of the BLOB. Such changes will eventually
commit if the transaction continues to completion.</p>
<p>Use the <a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a> interface to determine the size of
the opened blob. The size of a blob may not be changed by this
interface. Use the <a href="lang_update.html">UPDATE</a> SQL command to change the size of a
blob.</p>
<p>The <a href="#sqlite3_bind_blob">sqlite3_bind_zeroblob()</a> and <a href="#sqlite3_result_blob">sqlite3_result_zeroblob()</a> interfaces
and the built-in <a href="lang_corefunc.html#zeroblob">zeroblob</a> SQL function may be used to create a
zero-filled blob to read or write using the incremental-blob interface.</p>
<p>To avoid a resource leak, every open <a href="#sqlite3_blob">BLOB handle</a> should eventually
be released by a call to <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>.</p>
<p>See also: <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>,
<a href="#sqlite3_blob_reopen">sqlite3_blob_reopen()</a>, <a href="#sqlite3_blob_read">sqlite3_blob_read()</a>,
<a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a>, <a href="#sqlite3_blob_write">sqlite3_blob_write()</a>.
</p><hr><a name="sqlite3_blob_read"></a>
<h2>Read Data From A BLOB Incrementally</h2>
</div>
<blockquote><pre>
int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
</pre></blockquote>
<p>
This function is used to read data from an open <a href="#sqlite3_blob">BLOB handle</a> into a
caller-supplied buffer. N bytes of data are copied into buffer Z
from the open BLOB, starting at offset iOffset.</p>
<p>If offset iOffset is less than N bytes from the end of the BLOB,
<a href="#SQLITE_ABORT">SQLITE_ERROR</a> is returned and no data is read. If N or iOffset is
less than zero, <a href="#SQLITE_ABORT">SQLITE_ERROR</a> is returned and no data is read.
The size of the blob (and hence the maximum value of N+iOffset)
can be determined using the <a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a> interface.</p>
<p>An attempt to read from an expired <a href="#sqlite3_blob">BLOB handle</a> fails with an
error code of <a href="#SQLITE_ABORT">SQLITE_ABORT</a>.</p>
<p>On success, sqlite3_blob_read() returns SQLITE_OK.
Otherwise, an <a href="rescode.html">error code</a> or an <a href="rescode.html#extrc">extended error code</a> is returned.</p>
<p>This routine only works on a <a href="#sqlite3_blob">BLOB handle</a> which has been created
by a prior successful call to <a href="#sqlite3_blob_open">sqlite3_blob_open()</a> and which has not
been closed by <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>. Passing any other pointer in
to this routine results in undefined and probably undesirable behavior.</p>
<p>See also: <a href="#sqlite3_blob_write">sqlite3_blob_write()</a>.
</p><hr><a name="sqlite3_blob_reopen"></a>
<h2>Move a BLOB Handle to a New Row</h2>
</div>
<blockquote><pre>
int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
</pre></blockquote>
<p>
This function is used to move an existing <a href="#sqlite3_blob">BLOB handle</a> so that it points
to a different row of the same database table. The new row is identified
by the rowid value passed as the second argument. Only the row can be
changed. The database, table and column on which the blob handle is open
remain the same. Moving an existing <a href="#sqlite3_blob">BLOB handle</a> to a new row is
faster than closing the existing handle and opening a new one.</p>
<p>The new row must meet the same criteria as for <a href="#sqlite3_blob_open">sqlite3_blob_open()</a> -
it must exist and there must be either a blob or text value stored in
the nominated column. If the new row is not present in the table, or if
it does not contain a blob or text value, or if another error occurs, an
SQLite error code is returned and the blob handle is considered aborted.
All subsequent calls to <a href="#sqlite3_blob_read">sqlite3_blob_read()</a>, <a href="#sqlite3_blob_write">sqlite3_blob_write()</a> or
<a href="#sqlite3_blob_reopen">sqlite3_blob_reopen()</a> on an aborted blob handle immediately return
SQLITE_ABORT. Calling <a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a> on an aborted blob handle
always returns zero.</p>
<p>This function sets the database handle error code and message.
</p><hr><a name="sqlite3_blob_write"></a>
<h2>Write Data Into A BLOB Incrementally</h2>
</div>
<blockquote><pre>
int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
</pre></blockquote>
<p>
This function is used to write data into an open <a href="#sqlite3_blob">BLOB handle</a> from a
caller-supplied buffer. N bytes of data are copied from the buffer Z
into the open BLOB, starting at offset iOffset.</p>
<p>On success, sqlite3_blob_write() returns SQLITE_OK.
Otherwise, an <a href="rescode.html">error code</a> or an <a href="rescode.html#extrc">extended error code</a> is returned.
Unless SQLITE_MISUSE is returned, this function sets the
<a href="#sqlite3">database connection</a> error code and message accessible via
<a href="#sqlite3_errcode">sqlite3_errcode()</a> and <a href="#sqlite3_errcode">sqlite3_errmsg()</a> and related functions.</p>
<p>If the <a href="#sqlite3_blob">BLOB handle</a> passed as the first argument was not opened for
writing (the flags parameter to <a href="#sqlite3_blob_open">sqlite3_blob_open()</a> was zero),
this function returns <a href="#SQLITE_ABORT">SQLITE_READONLY</a>.</p>
<p>This function may only modify the contents of the BLOB; it is
not possible to increase the size of a BLOB using this API.
If offset iOffset is less than N bytes from the end of the BLOB,
<a href="#SQLITE_ABORT">SQLITE_ERROR</a> is returned and no data is written. The size of the
BLOB (and hence the maximum value of N+iOffset) can be determined
using the <a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a> interface. If N or iOffset are less
than zero <a href="#SQLITE_ABORT">SQLITE_ERROR</a> is returned and no data is written.</p>
<p>An attempt to write to an expired <a href="#sqlite3_blob">BLOB handle</a> fails with an
error code of <a href="#SQLITE_ABORT">SQLITE_ABORT</a>. Writes to the BLOB that occurred
before the <a href="#sqlite3_blob">BLOB handle</a> expired are not rolled back by the
expiration of the handle, though of course those changes might
have been overwritten by the statement that expired the BLOB handle
or by other independent statements.</p>
<p>This routine only works on a <a href="#sqlite3_blob">BLOB handle</a> which has been created
by a prior successful call to <a href="#sqlite3_blob_open">sqlite3_blob_open()</a> and which has not
been closed by <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>. Passing any other pointer in
to this routine results in undefined and probably undesirable behavior.</p>
<p>See also: <a href="#sqlite3_blob_read">sqlite3_blob_read()</a>.
</p><hr><a name="sqlite3_busy_timeout"></a>
<h2>Set A Busy Timeout</h2>
</div>
<blockquote><pre>
int sqlite3_busy_timeout(sqlite3*, int ms);
</pre></blockquote>
<p>
This routine sets a <a href="#sqlite3_busy_handler">busy handler</a> that sleeps
for a specified amount of time when a table is locked. The handler
will sleep multiple times until at least "ms" milliseconds of sleeping
have accumulated. After at least "ms" milliseconds of sleeping,
the handler returns 0 which causes <a href="#sqlite3_step">sqlite3_step()</a> to return
<a href="#SQLITE_ABORT">SQLITE_BUSY</a>.</p>
<p>Calling this routine with an argument less than or equal to zero
turns off all busy handlers.</p>
<p>There can only be a single busy handler for a particular
<a href="#sqlite3">database connection</a> at any given moment. If another busy handler
was defined (using <a href="#sqlite3_busy_handler">sqlite3_busy_handler()</a>) prior to calling
this routine, that other busy handler is cleared.</p>
<p>See also: <a href="pragma.html#pragma_busy_timeout">PRAGMA busy_timeout</a>
</p><hr><a name="sqlite3_cancel_auto_extension"></a>
<h2>Cancel Automatic Extension Loading</h2>
</div>
<blockquote><pre>
int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
</pre></blockquote>
<p>
The <a href="#sqlite3_cancel_auto_extension">sqlite3_cancel_auto_extension(X)</a> interface unregisters the
initialization routine X that was registered using a prior call to
<a href="#sqlite3_auto_extension">sqlite3_auto_extension(X)</a>. The <a href="#sqlite3_cancel_auto_extension">sqlite3_cancel_auto_extension(X)</a>
routine returns 1 if initialization routine X was successfully
unregistered and it returns 0 if X was not on the list of initialization
routines.
</p><hr><a name="sqlite3_clear_bindings"></a>
<h2>Reset All Bindings On A Prepared Statement</h2>
</div>
<blockquote><pre>
int sqlite3_clear_bindings(sqlite3_stmt*);
</pre></blockquote>
<p>
Contrary to the intuition of many, <a href="#sqlite3_reset">sqlite3_reset()</a> does not reset
the <a href="#sqlite3_bind_blob">bindings</a> on a <a href="#sqlite3_stmt">prepared statement</a>.
Use this routine to reset all host parameters to NULL.
</p><hr><a name="sqlite3_column_count"></a>
<h2>Number Of Columns In A Result Set</h2>
</div>
<blockquote><pre>
int sqlite3_column_count(sqlite3_stmt *pStmt);
</pre></blockquote>
<p>
Return the number of columns in the result set returned by the
<a href="#sqlite3_stmt">prepared statement</a>. If this routine returns 0, that means the
<a href="#sqlite3_stmt">prepared statement</a> returns no data (for example an <a href="lang_update.html">UPDATE</a>).
However, just because this routine returns a positive number does not
mean that one or more rows of data will be returned. A SELECT statement
will always have a positive sqlite3_column_count() but depending on the
WHERE clause constraints and the table content, it might return no rows.</p>
<p>See also: <a href="#sqlite3_data_count">sqlite3_data_count()</a>
</p><hr><a name="sqlite3_config"></a>
<h2>Configuring The SQLite Library</h2>
</div>
<blockquote><pre>
int sqlite3_config(int, ...);
</pre></blockquote>
<p>
The sqlite3_config() interface is used to make global configuration
changes to SQLite in order to tune SQLite to the specific needs of
the application. The default configuration is recommended for most
applications and so this routine is usually not necessary. It is
provided to support rare applications with unusual needs.</p>
<p><b>The sqlite3_config() interface is not threadsafe. The application
must ensure that no other SQLite interfaces are invoked by other
threads while sqlite3_config() is running.</b></p>
<p>The first argument to sqlite3_config() is an integer
<a href="#SQLITE_CONFIG_COVERING_INDEX_SCAN">configuration option</a> that determines
what property of SQLite is to be configured. Subsequent arguments
vary depending on the <a href="#SQLITE_CONFIG_COVERING_INDEX_SCAN">configuration option</a>
in the first argument.</p>
<p>For most configuration options, the sqlite3_config() interface
may only be invoked prior to library initialization using
<a href="#sqlite3_initialize">sqlite3_initialize()</a> or after shutdown by <a href="#sqlite3_initialize">sqlite3_shutdown()</a>.
The exceptional configuration options that may be invoked at any time
are called "anytime configuration options".
If sqlite3_config() is called after <a href="#sqlite3_initialize">sqlite3_initialize()</a> and before
<a href="#sqlite3_initialize">sqlite3_shutdown()</a> with a first argument that is not an anytime
configuration option, then the sqlite3_config() call will return SQLITE_MISUSE.
Note, however, that sqlite3_config() can be called as part of the
implementation of an application-defined <a href="#sqlite3_initialize">sqlite3_os_init()</a>.</p>
<p>When a configuration option is set, sqlite3_config() returns <a href="#SQLITE_ABORT">SQLITE_OK</a>.
If the option is unknown or SQLite is unable to set the option
then this routine returns a non-zero <a href="rescode.html">error code</a>.
</p><hr><a name="sqlite3_context_db_handle"></a>
<h2>Database Connection For Functions</h2>
</div>
<blockquote><pre>
sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
</pre></blockquote>
<p>
The sqlite3_context_db_handle() interface returns a copy of
the pointer to the <a href="#sqlite3">database connection</a> (the 1st parameter)
of the <a href="#sqlite3_create_function">sqlite3_create_function()</a>
and <a href="#sqlite3_create_function">sqlite3_create_function16()</a> routines that originally
registered the application defined function.
</p><hr><a name="sqlite3_data_count"></a>
<h2>Number of columns in a result set</h2>
</div>
<blockquote><pre>
int sqlite3_data_count(sqlite3_stmt *pStmt);
</pre></blockquote>
<p>
The sqlite3_data_count(P) interface returns the number of columns in the
current row of the result set of <a href="#sqlite3_stmt">prepared statement</a> P.
If prepared statement P does not have results ready to return
(via calls to the <a href="#sqlite3_column_blob">sqlite3_column()</a> family of
interfaces) then sqlite3_data_count(P) returns 0.
The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
The sqlite3_data_count(P) routine returns 0 if the previous call to
<a href="#sqlite3_step">sqlite3_step</a>(P) returned <a href="#SQLITE_ABORT">SQLITE_DONE</a>. The sqlite3_data_count(P)
will return non-zero if previous call to <a href="#sqlite3_step">sqlite3_step</a>(P) returned
<a href="#SQLITE_ABORT">SQLITE_ROW</a>, except in the case of the <a href="pragma.html#pragma_incremental_vacuum">PRAGMA incremental_vacuum</a>
where it always returns zero since each step of that multi-step
pragma returns 0 columns of data.</p>
<p>See also: <a href="#sqlite3_column_count">sqlite3_column_count()</a>
</p><hr><a name="sqlite3_database_file_object"></a>
<h2>Database File Corresponding To A Journal</h2>
</div>
<blockquote><pre>
sqlite3_file *sqlite3_database_file_object(const char*);
</pre></blockquote>
<p>
If X is the name of a rollback or WAL-mode journal file that is
passed into the xOpen method of <a href="#sqlite3_vfs">sqlite3_vfs</a>, then
sqlite3_database_file_object(X) returns a pointer to the <a href="#sqlite3_file">sqlite3_file</a>
object that represents the main database file.</p>
<p>This routine is intended for use in custom <a href="vfs.html">VFS</a> implementations
only. It is not a general-purpose interface.
The argument sqlite3_file_object(X) must be a filename pointer that
has been passed into <a href="#sqlite3_vfs">sqlite3_vfs</a>.xOpen method where the
flags parameter to xOpen contains one of the bits
<a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_MAIN_JOURNAL</a> or <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_WAL</a>. Any other use
of this routine results in undefined and probably undesirable
behavior.
</p><hr><a name="sqlite3_db_cacheflush"></a>
<h2>Flush caches to disk mid-transaction</h2>
</div>
<blockquote><pre>
int sqlite3_db_cacheflush(sqlite3*);
</pre></blockquote>
<p>
If a write-transaction is open on <a href="#sqlite3">database connection</a> D when the
<a href="#sqlite3_db_cacheflush">sqlite3_db_cacheflush(D)</a> interface invoked, any dirty
pages in the pager-cache that are not currently in use are written out
to disk. A dirty page may be in use if a database cursor created by an
active SQL statement is reading from it, or if it is page 1 of a database
file (page 1 is always "in use"). The <a href="#sqlite3_db_cacheflush">sqlite3_db_cacheflush(D)</a>
interface flushes caches for all schemas - "main", "temp", and
any <a href="lang_attach.html">attached</a> databases.</p>
<p>If this function needs to obtain extra database locks before dirty pages
can be flushed to disk, it does so. If those locks cannot be obtained
immediately and there is a busy-handler callback configured, it is invoked
in the usual manner. If the required lock still cannot be obtained, then
the database is skipped and an attempt made to flush any dirty pages
belonging to the next (if any) database. If any databases are skipped
because locks cannot be obtained, but no other error occurs, this
function returns SQLITE_BUSY.</p>
<p>If any other error occurs while flushing dirty pages to disk (for
example an IO error or out-of-memory condition), then processing is
abandoned and an SQLite <a href="rescode.html">error code</a> is returned to the caller immediately.</p>
<p>Otherwise, if no error occurs, <a href="#sqlite3_db_cacheflush">sqlite3_db_cacheflush()</a> returns SQLITE_OK.</p>
<p>This function does not set the database handle error code or message
returned by the <a href="#sqlite3_errcode">sqlite3_errcode()</a> and <a href="#sqlite3_errcode">sqlite3_errmsg()</a> functions.
</p><hr><a name="sqlite3_db_config"></a>
<h2>Configure database connections</h2>
</div>
<blockquote><pre>
int sqlite3_db_config(sqlite3*, int op, ...);
</pre></blockquote>
<p>
The sqlite3_db_config() interface is used to make configuration
changes to a <a href="#sqlite3">database connection</a>. The interface is similar to
<a href="#sqlite3_config">sqlite3_config()</a> except that the changes apply to a single
<a href="#sqlite3">database connection</a> (specified in the first argument).</p>
<p>The second argument to sqlite3_db_config(D,V,...) is the
<a href="#sqlitedbconfiglookaside">configuration verb</a> - an integer code
that indicates what aspect of the <a href="#sqlite3">database connection</a> is being configured.
Subsequent arguments vary depending on the configuration verb.</p>
<p>Calls to sqlite3_db_config() return SQLITE_OK if and only if
the call is considered successful.
</p><hr><a name="sqlite3_db_filename"></a>
<h2>Return The Filename For A Database Connection</h2>
</div>
<blockquote><pre>
sqlite3_filename sqlite3_db_filename(sqlite3 *db, const char *zDbName);
</pre></blockquote>
<p>
The sqlite3_db_filename(D,N) interface returns a pointer to the filename
associated with database N of connection D.
If there is no attached database N on the database
connection D, or if database N is a temporary or in-memory database, then
this function will return either a NULL pointer or an empty string.</p>
<p>The string value returned by this routine is owned and managed by
the database connection. The value will be valid until the database N
is <a href="lang_detach.html">DETACH</a>-ed or until the database connection closes.</p>
<p>The filename returned by this function is the output of the
xFullPathname method of the <a href="vfs.html">VFS</a>. In other words, the filename
will be an absolute pathname, even if the filename used
to open the database originally was a URI or relative pathname.</p>
<p>If the filename pointer returned by this routine is not NULL, then it
can be used as the filename input parameter to these routines:
<ul>
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_parameter()</a>
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_boolean()</a>
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_int64()</a>
<li> <a href="#sqlite3_filename_database">sqlite3_filename_database()</a>
<li> <a href="#sqlite3_filename_database">sqlite3_filename_journal()</a>
<li> <a href="#sqlite3_filename_database">sqlite3_filename_wal()</a>
</ul>
</p><hr><a name="sqlite3_db_handle"></a>
<h2>Find The Database Handle Of A Prepared Statement</h2>
</div>
<blockquote><pre>
sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
</pre></blockquote>
<p>
The sqlite3_db_handle interface returns the <a href="#sqlite3">database connection</a> handle
to which a <a href="#sqlite3_stmt">prepared statement</a> belongs. The <a href="#sqlite3">database connection</a>
returned by sqlite3_db_handle is the same <a href="#sqlite3">database connection</a>
that was the first argument
to the <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> call (or its variants) that was used to
create the statement in the first place.
</p><hr><a name="sqlite3_db_mutex"></a>
<h2>Retrieve the mutex for a database connection</h2>
</div>
<blockquote><pre>
sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
</pre></blockquote>
<p>
This interface returns a pointer the <a href="#sqlite3_mutex">sqlite3_mutex</a> object that
serializes access to the <a href="#sqlite3">database connection</a> given in the argument
when the <a href="threadsafe.html">threading mode</a> is Serialized.
If the <a href="threadsafe.html">threading mode</a> is Single-thread or Multi-thread then this
routine returns a NULL pointer.
</p><hr><a name="sqlite3_db_name"></a>
<h2>Return The Schema Name For A Database Connection</h2>
</div>
<blockquote><pre>
const char *sqlite3_db_name(sqlite3 *db, int N);
</pre></blockquote>
<p>
The sqlite3_db_name(D,N) interface returns a pointer to the schema name
for the N-th database on database connection D, or a NULL pointer of N is
out of range. An N value of 0 means the main database file. An N of 1 is
the "temp" schema. Larger values of N correspond to various ATTACH-ed
databases.</p>
<p>Space to hold the string that is returned by sqlite3_db_name() is managed
by SQLite itself. The string might be deallocated by any operation that
changes the schema, including <a href="lang_attach.html">ATTACH</a> or <a href="lang_detach.html">DETACH</a> or calls to
<a href="#sqlite3_serialize">sqlite3_serialize()</a> or <a href="#sqlite3_deserialize">sqlite3_deserialize()</a>, even operations that
occur on a different thread. Applications that need to
remember the string long-term should make their own copy. Applications that
are accessing the same database connection simultaneously on multiple
threads should mutex-protect calls to this API and should make their own
private copy of the result prior to releasing the mutex.
</p><hr><a name="sqlite3_db_readonly"></a>
<h2>Determine if a database is read-only</h2>
</div>
<blockquote><pre>
int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
</pre></blockquote>
<p>
The sqlite3_db_readonly(D,N) interface returns 1 if the database N
of connection D is read-only, 0 if it is read/write, or -1 if N is not
the name of a database on connection D.
</p><hr><a name="sqlite3_db_release_memory"></a>
<h2>Free Memory Used By A Database Connection</h2>
</div>
<blockquote><pre>
int sqlite3_db_release_memory(sqlite3*);
</pre></blockquote>
<p>
The sqlite3_db_release_memory(D) interface attempts to free as much heap
memory as possible from database connection D. Unlike the
<a href="#sqlite3_release_memory">sqlite3_release_memory()</a> interface, this interface is in effect even
when the <a href="compile.html#enable_memory_management">SQLITE_ENABLE_MEMORY_MANAGEMENT</a> compile-time option is
omitted.</p>
<p>See also: <a href="#sqlite3_release_memory">sqlite3_release_memory()</a>
</p><hr><a name="sqlite3_db_status"></a>
<h2>Database Connection Status</h2>
</div>
<blockquote><pre>
int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
</pre></blockquote>
<p>
This interface is used to retrieve runtime status information
about a single <a href="#sqlite3">database connection</a>. The first argument is the
database connection object to be interrogated. The second argument
is an integer constant, taken from the set of
<a href="#SQLITE_DBSTATUS options">SQLITE_DBSTATUS options</a>, that
determines the parameter to interrogate. The set of
<a href="#SQLITE_DBSTATUS options">SQLITE_DBSTATUS options</a> is likely
to grow in future releases of SQLite.</p>
<p>The current value of the requested parameter is written into *pCur
and the highest instantaneous value is written into *pHiwtr. If
the resetFlg is true, then the highest instantaneous value is
reset back down to the current value.</p>
<p>The sqlite3_db_status() routine returns SQLITE_OK on success and a
non-zero <a href="rescode.html">error code</a> on failure.</p>
<p>See also: <a href="#sqlite3_status">sqlite3_status()</a> and <a href="#sqlite3_stmt_status">sqlite3_stmt_status()</a>.
</p><hr><a name="sqlite3_declare_vtab"></a>
<h2>Declare The Schema Of A Virtual Table</h2>
</div>
<blockquote><pre>
int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
</pre></blockquote>
<p>
The <a href="vtab.html#xcreate">xCreate</a> and <a href="vtab.html#xconnect">xConnect</a> methods of a
<a href="#sqlite3_module">virtual table module</a> call this interface
to declare the format (the names and datatypes of the columns) of
the virtual tables they implement.
</p><hr><a name="sqlite3_deserialize"></a>
<h2>Deserialize a database</h2>
</div>
<blockquote><pre>
int sqlite3_deserialize(
sqlite3 *db, /* The database connection */
const char *zSchema, /* Which DB to reopen with the deserialization */
unsigned char *pData, /* The serialized database content */
sqlite3_int64 szDb, /* Number bytes in the deserialization */
sqlite3_int64 szBuf, /* Total size of buffer pData[] */
unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */
);
</pre></blockquote>
<p>
The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
<a href="#sqlite3">database connection</a> D to disconnect from database S and then
reopen S as an in-memory database based on the serialization contained
in P. The serialized database P is N bytes in size. M is the size of
the buffer P, which might be larger than N. If M is larger than N, and
the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
permitted to add content to the in-memory database as long as the total
size does not exceed M bytes.</p>
<p>If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
invoke sqlite3_free() on the serialization buffer when the database
connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
SQLite will try to increase the buffer size using sqlite3_realloc64()
if writes on the database cause it to grow larger than M bytes.</p>
<p>Applications must not modify the buffer P or invalidate it before
the database connection D is closed.</p>
<p>The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
database is currently in a read transaction or is involved in a backup
operation.</p>
<p>It is not possible to deserialized into the TEMP database. If the
S argument to sqlite3_deserialize(D,S,P,N,M,F) is "temp" then the
function returns SQLITE_ERROR.</p>
<p>The deserialized database should not be in <a href="wal.html">WAL mode</a>. If the database
is in WAL mode, then any attempt to use the database file will result
in an <a href="#SQLITE_ABORT">SQLITE_CANTOPEN</a> error. The application can set the
<a href="fileformat2.html#vnums">file format version numbers</a> (bytes 18 and 19) of the input database P
to 0x01 prior to invoking sqlite3_deserialize(D,S,P,N,M,F) to force the
database file into rollback mode and work around this limitation.</p>
<p>If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
<a href="#sqlite3_free">sqlite3_free()</a> is invoked on argument P prior to returning.</p>
<p>This interface is omitted if SQLite is compiled with the
<a href="compile.html#omit_deserialize">SQLITE_OMIT_DESERIALIZE</a> option.
</p><hr><a name="sqlite3_drop_modules"></a>
<h2>Remove Unnecessary Virtual Table Implementations</h2>
</div>
<blockquote><pre>
int sqlite3_drop_modules(
sqlite3 *db, /* Remove modules from this connection */
const char **azKeep /* Except, do not remove the ones named here */
);
</pre></blockquote>
<p>
The sqlite3_drop_modules(D,L) interface removes all virtual
table modules from database connection D except those named on list L.
The L parameter must be either NULL or a pointer to an array of pointers
to strings where the array is terminated by a single NULL pointer.
If the L parameter is NULL, then all virtual table modules are removed.</p>
<p>See also: <a href="#sqlite3_create_module">sqlite3_create_module()</a>
</p><hr><a name="sqlite3_enable_load_extension"></a>
<h2>Enable Or Disable Extension Loading</h2>
</div>
<blockquote><pre>
int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
</pre></blockquote>
<p>
So as not to open security holes in older applications that are
unprepared to deal with <a href="loadext.html">extension loading</a>, and as a means of disabling
<a href="loadext.html">extension loading</a> while evaluating user-entered SQL, the following API
is provided to turn the <a href="#sqlite3_load_extension">sqlite3_load_extension()</a> mechanism on and off.</p>
<p>Extension loading is off by default.
Call the sqlite3_enable_load_extension() routine with onoff==1
to turn extension loading on and call it with onoff==0 to turn
it back off again.</p>
<p>This interface enables or disables both the C-API
<a href="#sqlite3_load_extension">sqlite3_load_extension()</a> and the SQL function <a href="lang_corefunc.html#load_extension">load_extension()</a>.
Use <a href="#sqlite3_db_config">sqlite3_db_config</a>(db,<a href="#sqlitedbconfigenableloadextension">SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</a>,..)
to enable or disable only the C-API.</p>
<p><b>Security warning:</b> It is recommended that extension loading
be enabled using the <a href="#sqlitedbconfigenableloadextension">SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</a> method
rather than this interface, so the <a href="lang_corefunc.html#load_extension">load_extension()</a> SQL function
remains disabled. This will prevent SQL injections from giving attackers
access to extension loading capabilities.
</p><hr><a name="sqlite3_enable_shared_cache"></a>
<h2>Enable Or Disable Shared Pager Cache</h2>
</div>
<blockquote><pre>
int sqlite3_enable_shared_cache(int);
</pre></blockquote>
<p>
This routine enables or disables the sharing of the database cache
and schema data structures between <a href="#sqlite3">connections</a>
to the same database. Sharing is enabled if the argument is true
and disabled if the argument is false.</p>
<p>This interface is omitted if SQLite is compiled with
<a href="compile.html#omit_shared_cache">-DSQLITE_OMIT_SHARED_CACHE</a>. The <a href="compile.html#omit_shared_cache">-DSQLITE_OMIT_SHARED_CACHE</a>
compile-time option is recommended because the
<a href="sharedcache.html#dontuse">use of shared cache mode is discouraged</a>.</p>
<p>Cache sharing is enabled and disabled for an entire process.
This is a change as of SQLite <a href="releaselog/3_5_0.html">version 3.5.0</a> (2007-09-04).
In prior versions of SQLite,
sharing was enabled or disabled for each thread separately.</p>
<p>The cache sharing mode set by this interface effects all subsequent
calls to <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open_v2()</a>, and <a href="#sqlite3_open">sqlite3_open16()</a>.
Existing database connections continue to use the sharing mode
that was in effect at the time they were opened.</p>
<p>This routine returns <a href="#SQLITE_ABORT">SQLITE_OK</a> if shared cache was enabled or disabled
successfully. An <a href="rescode.html">error code</a> is returned otherwise.</p>
<p>Shared cache is disabled by default. It is recommended that it stay
that way. In other words, do not use this routine. This interface
continues to be provided for historical compatibility, but its use is
discouraged. Any use of shared cache is discouraged. If shared cache
must be used, it is recommended that shared cache only be enabled for
individual database connections using the <a href="#sqlite3_open">sqlite3_open_v2()</a> interface
with the <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_SHAREDCACHE</a> flag.</p>
<p>Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
and will always return SQLITE_MISUSE. On those systems,
shared cache mode should be enabled per-database connection via
<a href="#sqlite3_open">sqlite3_open_v2()</a> with <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_SHAREDCACHE</a>.</p>
<p>This interface is threadsafe on processors where writing a
32-bit integer is atomic.</p>
<p>See Also: <a href="sharedcache.html">SQLite Shared-Cache Mode</a>
</p><hr><a name="sqlite3_exec"></a>
<h2>One-Step Query Execution Interface</h2>
</div>
<blockquote><pre>
int sqlite3_exec(
sqlite3*, /* An open database */
const char *sql, /* SQL to be evaluated */
int (*callback)(void*,int,char**,char**), /* Callback function */
void *, /* 1st argument to callback */
char **errmsg /* Error msg written here */
);
</pre></blockquote>
<p>
The sqlite3_exec() interface is a convenience wrapper around
<a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>, <a href="#sqlite3_step">sqlite3_step()</a>, and <a href="#sqlite3_finalize">sqlite3_finalize()</a>,
that allows an application to run multiple statements of SQL
without having to use a lot of C code.</p>
<p>The sqlite3_exec() interface runs zero or more UTF-8 encoded,
semicolon-separate SQL statements passed into its 2nd argument,
in the context of the <a href="#sqlite3">database connection</a> passed in as its 1st
argument. If the callback function of the 3rd argument to
sqlite3_exec() is not NULL, then it is invoked for each result row
coming out of the evaluated SQL statements. The 4th argument to
sqlite3_exec() is relayed through to the 1st argument of each
callback invocation. If the callback pointer to sqlite3_exec()
is NULL, then no callback is ever invoked and result rows are
ignored.</p>
<p>If an error occurs while evaluating the SQL statements passed into
sqlite3_exec(), then execution of the current statement stops and
subsequent statements are skipped. If the 5th parameter to sqlite3_exec()
is not NULL then any error message is written into memory obtained
from <a href="#sqlite3_free">sqlite3_malloc()</a> and passed back through the 5th parameter.
To avoid memory leaks, the application should invoke <a href="#sqlite3_free">sqlite3_free()</a>
on error message strings returned through the 5th parameter of
sqlite3_exec() after the error message string is no longer needed.
If the 5th parameter to sqlite3_exec() is not NULL and no errors
occur, then sqlite3_exec() sets the pointer in its 5th parameter to
NULL before returning.</p>
<p>If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
routine returns SQLITE_ABORT without invoking the callback again and
without running any subsequent SQL statements.</p>
<p>The 2nd argument to the sqlite3_exec() callback function is the
number of columns in the result. The 3rd argument to the sqlite3_exec()
callback is an array of pointers to strings obtained as if from
<a href="#sqlite3_column_blob">sqlite3_column_text()</a>, one for each column. If an element of a
result row is NULL then the corresponding string pointer for the
sqlite3_exec() callback is a NULL pointer. The 4th argument to the
sqlite3_exec() callback is an array of pointers to strings where each
entry represents the name of corresponding result column as obtained
from <a href="#sqlite3_column_name">sqlite3_column_name()</a>.</p>
<p>If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
to an empty string, or a pointer that contains only whitespace and/or
SQL comments, then no SQL statements are evaluated and the database
is not changed.</p>
<p>Restrictions:</p>
<p><ul>
<li> The application must ensure that the 1st parameter to sqlite3_exec()
is a valid and open <a href="#sqlite3">database connection</a>.
<li> The application must not close the <a href="#sqlite3">database connection</a> specified by
the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
<li> The application must not modify the SQL statement text passed into
the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
<li> The application must not dereference the arrays or string pointers
passed as the 3rd and 4th callback parameters after it returns.
</ul>
</p><hr><a name="sqlite3_extended_result_codes"></a>
<h2>Enable Or Disable Extended Result Codes</h2>
</div>
<blockquote><pre>
int sqlite3_extended_result_codes(sqlite3*, int onoff);
</pre></blockquote>
<p>
The sqlite3_extended_result_codes() routine enables or disables the
<a href="rescode.html#extrc">extended result codes</a> feature of SQLite. The extended result
codes are disabled by default for historical compatibility.
</p><hr><a name="sqlite3_finalize"></a>
<h2>Destroy A Prepared Statement Object</h2>
</div>
<blockquote><pre>
int sqlite3_finalize(sqlite3_stmt *pStmt);
</pre></blockquote>
<p>
The sqlite3_finalize() function is called to delete a <a href="#sqlite3_stmt">prepared statement</a>.
If the most recent evaluation of the statement encountered no errors
or if the statement is never been evaluated, then sqlite3_finalize() returns
SQLITE_OK. If the most recent evaluation of statement S failed, then
sqlite3_finalize(S) returns the appropriate <a href="rescode.html">error code</a> or
<a href="rescode.html#extrc">extended error code</a>.</p>
<p>The sqlite3_finalize(S) routine can be called at any point during
the life cycle of <a href="#sqlite3_stmt">prepared statement</a> S:
before statement S is ever evaluated, after
one or more calls to <a href="#sqlite3_reset">sqlite3_reset()</a>, or after any call
to <a href="#sqlite3_step">sqlite3_step()</a> regardless of whether or not the statement has
completed execution.</p>
<p>Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.</p>
<p>The application must finalize every <a href="#sqlite3_stmt">prepared statement</a> in order to avoid
resource leaks. It is a grievous error for the application to try to use
a prepared statement after it has been finalized. Any use of a prepared
statement after it has been finalized can result in undefined and
undesirable behavior such as segfaults and heap corruption.
</p><hr><a name="sqlite3_last_insert_rowid"></a>
<h2>Last Insert Rowid</h2>
</div>
<blockquote><pre>
sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
</pre></blockquote>
<p>
Each entry in most SQLite tables (except for <a href="withoutrowid.html">WITHOUT ROWID</a> tables)
has a unique 64-bit signed
integer key called the <a href="lang_createtable.html#rowid">"rowid"</a>. The rowid is always available
as an undeclared column named ROWID, OID, or _ROWID_ as long as those
names are not also used by explicitly declared columns. If
the table has a column of type <a href="lang_createtable.html#rowid">INTEGER PRIMARY KEY</a> then that column
is another alias for the rowid.</p>
<p>The sqlite3_last_insert_rowid(D) interface usually returns the <a href="lang_createtable.html#rowid">rowid</a> of
the most recent successful <a href="lang_insert.html">INSERT</a> into a rowid table or <a href="vtab.html">virtual table</a>
on database connection D. Inserts into <a href="withoutrowid.html">WITHOUT ROWID</a> tables are not
recorded. If no successful <a href="lang_insert.html">INSERT</a>s into rowid tables have ever occurred
on the database connection D, then sqlite3_last_insert_rowid(D) returns
zero.</p>
<p>As well as being set automatically as rows are inserted into database
tables, the value returned by this function may be set explicitly by
<a href="#sqlite3_set_last_insert_rowid">sqlite3_set_last_insert_rowid()</a></p>
<p>Some virtual table implementations may INSERT rows into rowid tables as
part of committing a transaction (e.g. to flush data accumulated in memory
to disk). In this case subsequent calls to this function return the rowid
associated with these internal INSERT operations, which leads to
unintuitive results. Virtual table implementations that do write to rowid
tables in this way can avoid this problem by restoring the original
rowid value using <a href="#sqlite3_set_last_insert_rowid">sqlite3_set_last_insert_rowid()</a> before returning
control to the user.</p>
<p>If an <a href="lang_insert.html">INSERT</a> occurs within a trigger then this routine will
return the <a href="lang_createtable.html#rowid">rowid</a> of the inserted row as long as the trigger is
running. Once the trigger program ends, the value returned
by this routine reverts to what it was before the trigger was fired.</p>
<p>An <a href="lang_insert.html">INSERT</a> that fails due to a constraint violation is not a
successful <a href="lang_insert.html">INSERT</a> and does not change the value returned by this
routine. Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
and INSERT OR ABORT make no changes to the return value of this
routine when their insertion fails. When INSERT OR REPLACE
encounters a constraint violation, it does not fail. The
INSERT continues to completion after deleting rows that caused
the constraint problem so INSERT OR REPLACE will always change
the return value of this interface.</p>
<p>For the purposes of this routine, an <a href="lang_insert.html">INSERT</a> is considered to
be successful even if it is subsequently rolled back.</p>
<p>This function is accessible to SQL statements via the
<a href="lang_corefunc.html#last_insert_rowid">last_insert_rowid() SQL function</a>.</p>
<p>If a separate thread performs a new <a href="lang_insert.html">INSERT</a> on the same
database connection while the <a href="#sqlite3_last_insert_rowid">sqlite3_last_insert_rowid()</a>
function is running and thus changes the last insert <a href="lang_createtable.html#rowid">rowid</a>,
then the value returned by <a href="#sqlite3_last_insert_rowid">sqlite3_last_insert_rowid()</a> is
unpredictable and might not equal either the old or the new
last insert <a href="lang_createtable.html#rowid">rowid</a>.
</p><hr><a name="sqlite3_limit"></a>
<h2>Run-time Limits</h2>
</div>
<blockquote><pre>
int sqlite3_limit(sqlite3*, int id, int newVal);
</pre></blockquote>
<p>
This interface allows the size of various constructs to be limited
on a connection by connection basis. The first parameter is the
<a href="#sqlite3">database connection</a> whose limit is to be set or queried. The
second parameter is one of the <a href="#SQLITE_LIMIT_ATTACHED">limit categories</a> that define a
class of constructs to be size limited. The third parameter is the
new limit for that construct.</p>
<p>If the new limit is a negative number, the limit is unchanged.
For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
<a href="limits.html">hard upper bound</a>
set at compile-time by a C preprocessor macro called
<a href="limits.html">SQLITE_MAX_<i>NAME</i></a>.
(The "_LIMIT_" in the name is changed to "_MAX_".)
Attempts to increase a limit above its hard upper bound are
silently truncated to the hard upper bound.</p>
<p>Regardless of whether or not the limit was changed, the
<a href="#sqlite3_limit">sqlite3_limit()</a> interface returns the prior value of the limit.
Hence, to find the current value of a limit without changing it,
simply invoke this interface with the third parameter set to -1.</p>
<p>Run-time limits are intended for use in applications that manage
both their own internal database and also databases that are controlled
by untrusted external sources. An example application might be a
web browser that has its own databases for storing history and
separate databases controlled by JavaScript applications downloaded
off the Internet. The internal databases can be given the
large, default limits. Databases managed by external sources can
be given much smaller limits designed to prevent a denial of service
attack. Developers might also want to use the <a href="#sqlite3_set_authorizer">sqlite3_set_authorizer()</a>
interface to further control untrusted SQL. The size of the database
created by an untrusted script can be contained using the
<a href="pragma.html#pragma_max_page_count">max_page_count</a> <a href="pragma.html#syntax">PRAGMA</a>.</p>
<p>New run-time limit categories may be added in future releases.
</p><hr><a name="sqlite3_load_extension"></a>
<h2>Load An Extension</h2>
</div>
<blockquote><pre>
int sqlite3_load_extension(
sqlite3 *db, /* Load the extension into this database connection */
const char *zFile, /* Name of the shared library containing extension */
const char *zProc, /* Entry point. Derived from zFile if 0 */
char **pzErrMsg /* Put error message here if not 0 */
);
</pre></blockquote>
<p>
This interface loads an SQLite extension library from the named file.</p>
<p>The sqlite3_load_extension() interface attempts to load an
<a href="loadext.html">SQLite extension</a> library contained in the file zFile. If
the file cannot be loaded directly, attempts are made to load
with various operating-system specific extensions added.
So for example, if "samplelib" cannot be loaded, then names like
"samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
be tried also.</p>
<p>The entry point is zProc.
zProc may be 0, in which case SQLite will try to come up with an
entry point name on its own. It first tries "sqlite3_extension_init".
If that does not work, it constructs a name "sqlite3_X_init" where the
X is consists of the lower-case equivalent of all ASCII alphabetic
characters in the filename from the last "/" to the first following
"." and omitting any initial "lib".
The sqlite3_load_extension() interface returns
<a href="#SQLITE_ABORT">SQLITE_OK</a> on success and <a href="#SQLITE_ABORT">SQLITE_ERROR</a> if something goes wrong.
If an error occurs and pzErrMsg is not 0, then the
<a href="#sqlite3_load_extension">sqlite3_load_extension()</a> interface shall attempt to
fill *pzErrMsg with error message text stored in memory
obtained from <a href="#sqlite3_free">sqlite3_malloc()</a>. The calling function
should free this memory by calling <a href="#sqlite3_free">sqlite3_free()</a>.</p>
<p>Extension loading must be enabled using
<a href="#sqlite3_enable_load_extension">sqlite3_enable_load_extension()</a> or
<a href="#sqlite3_db_config">sqlite3_db_config</a>(db,<a href="#sqlitedbconfigenableloadextension">SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</a>,1,NULL)
prior to calling this API,
otherwise an error will be returned.</p>
<p><b>Security warning:</b> It is recommended that the
<a href="#sqlitedbconfigenableloadextension">SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</a> method be used to enable only this
interface. The use of the <a href="#sqlite3_enable_load_extension">sqlite3_enable_load_extension()</a> interface
should be avoided. This will keep the SQL function <a href="lang_corefunc.html#load_extension">load_extension()</a>
disabled and prevent SQL injections from giving attackers
access to extension loading capabilities.</p>
<p>See also the <a href="lang_corefunc.html#load_extension">load_extension() SQL function</a>.
</p><hr><a name="sqlite3_log"></a>
<h2>Error Logging Interface</h2>
</div>
<blockquote><pre>
void sqlite3_log(int iErrCode, const char *zFormat, ...);
</pre></blockquote>
<p>
The <a href="#sqlite3_log">sqlite3_log()</a> interface writes a message into the <a href="errlog.html">error log</a>
established by the <a href="#sqliteconfiglog">SQLITE_CONFIG_LOG</a> option to <a href="#sqlite3_config">sqlite3_config()</a>.
If logging is enabled, the zFormat string and subsequent arguments are
used with <a href="#sqlite3_mprintf">sqlite3_snprintf()</a> to generate the final output string.</p>
<p>The sqlite3_log() interface is intended for use by extensions such as
virtual tables, collating functions, and SQL functions. While there is
nothing to prevent an application from calling sqlite3_log(), doing so
is considered bad form.</p>
<p>The zFormat string must not be NULL.</p>
<p>To avoid deadlocks and other threading problems, the sqlite3_log() routine
will not use dynamically allocated memory. The log message is stored in
a fixed-length buffer on the stack. If the log message is longer than
a few hundred characters, it will be truncated to the length of the
buffer.
</p><hr><a name="sqlite3_next_stmt"></a>
<h2>Find the next prepared statement</h2>
</div>
<blockquote><pre>
sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
</pre></blockquote>
<p>
This interface returns a pointer to the next <a href="#sqlite3_stmt">prepared statement</a> after
pStmt associated with the <a href="#sqlite3">database connection</a> pDb. If pStmt is NULL
then this interface returns a pointer to the first prepared statement
associated with the database connection pDb. If no prepared statement
satisfies the conditions of this routine, it returns NULL.</p>
<p>The <a href="#sqlite3">database connection</a> pointer D in a call to
<a href="#sqlite3_next_stmt">sqlite3_next_stmt(D,S)</a> must refer to an open database
connection and in particular must not be a NULL pointer.
</p><hr><a name="sqlite3_overload_function"></a>
<h2>Overload A Function For A Virtual Table</h2>
</div>
<blockquote><pre>
int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
</pre></blockquote>
<p>
Virtual tables can provide alternative implementations of functions
using the <a href="vtab.html#xfindfunction">xFindFunction</a> method of the <a href="#sqlite3_module">virtual table module</a>.
But global versions of those functions
must exist in order to be overloaded.</p>
<p>This API makes sure a global version of a function with a particular
name and number of parameters exists. If no such function exists
before this API is called, a new function is created. The implementation
of the new function always causes an exception to be thrown. So
the new function is not good for anything by itself. Its only
purpose is to be a placeholder function that can be overloaded
by a <a href="vtab.html">virtual table</a>.
</p><hr><a name="sqlite3_progress_handler"></a>
<h2>Query Progress Callbacks</h2>
</div>
<blockquote><pre>
void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
</pre></blockquote>
<p>
The sqlite3_progress_handler(D,N,X,P) interface causes the callback
function X to be invoked periodically during long running calls to
<a href="#sqlite3_step">sqlite3_step()</a> and <a href="#sqlite3_prepare">sqlite3_prepare()</a> and similar for
database connection D. An example use for this
interface is to keep a GUI updated during a large query.</p>
<p>The parameter P is passed through as the only parameter to the
callback function X. The parameter N is the approximate number of
<a href="opcode.html">virtual machine instructions</a> that are evaluated between successive
invocations of the callback X. If N is less than one then the progress
handler is disabled.</p>
<p>Only a single progress handler may be defined at one time per
<a href="#sqlite3">database connection</a>; setting a new progress handler cancels the
old one. Setting parameter X to NULL disables the progress handler.
The progress handler is also disabled by setting N to a value less
than 1.</p>
<p>If the progress callback returns non-zero, the operation is
interrupted. This feature can be used to implement a
"Cancel" button on a GUI progress dialog box.</p>
<p>The progress handler callback must not do anything that will modify
the database connection that invoked the progress handler.
Note that <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> and <a href="#sqlite3_step">sqlite3_step()</a> both modify their
database connections for the meaning of "modify" in this paragraph.</p>
<p>The progress handler callback would originally only be invoked from the
bytecode engine. It still might be invoked during <a href="#sqlite3_prepare">sqlite3_prepare()</a>
and similar because those routines might force a reparse of the schema
which involves running the bytecode engine. However, beginning with
SQLite version 3.41.0, the progress handler callback might also be
invoked directly from <a href="#sqlite3_prepare">sqlite3_prepare()</a> while analyzing and generating
code for complex queries.
</p><hr><a name="sqlite3_randomness"></a>
<h2>Pseudo-Random Number Generator</h2>
</div>
<blockquote><pre>
void sqlite3_randomness(int N, void *P);
</pre></blockquote>
<p>
SQLite contains a high-quality pseudo-random number generator (PRNG) used to
select random <a href="lang_createtable.html#rowid">ROWIDs</a> when inserting new records into a table that
already uses the largest possible <a href="lang_createtable.html#rowid">ROWID</a>. The PRNG is also used for
the built-in random() and randomblob() SQL functions. This interface allows
applications to access the same PRNG for other purposes.</p>
<p>A call to this routine stores N bytes of randomness into buffer P.
The P parameter can be a NULL pointer.</p>
<p>If this routine has not been previously called or if the previous
call had N less than one or a NULL pointer for P, then the PRNG is
seeded using randomness obtained from the xRandomness method of
the default <a href="#sqlite3_vfs">sqlite3_vfs</a> object.
If the previous call to this routine had an N of 1 or more and a
non-NULL P then the pseudo-randomness is generated
internally and without recourse to the <a href="#sqlite3_vfs">sqlite3_vfs</a> xRandomness
method.
</p><hr><a name="sqlite3_release_memory"></a>
<h2>Attempt To Free Heap Memory</h2>
</div>
<blockquote><pre>
int sqlite3_release_memory(int);
</pre></blockquote>
<p>
The sqlite3_release_memory() interface attempts to free N bytes
of heap memory by deallocating non-essential memory allocations
held by the database library. Memory used to cache database
pages to improve performance is an example of non-essential memory.
sqlite3_release_memory() returns the number of bytes actually freed,
which might be more or less than the amount requested.
The sqlite3_release_memory() routine is a no-op returning zero
if SQLite is not compiled with <a href="compile.html#enable_memory_management">SQLITE_ENABLE_MEMORY_MANAGEMENT</a>.</p>
<p>See also: <a href="#sqlite3_db_release_memory">sqlite3_db_release_memory()</a>
</p><hr><a name="sqlite3_reset"></a>
<h2>Reset A Prepared Statement Object</h2>
</div>
<blockquote><pre>
int sqlite3_reset(sqlite3_stmt *pStmt);
</pre></blockquote>
<p>
The sqlite3_reset() function is called to reset a <a href="#sqlite3_stmt">prepared statement</a>
object back to its initial state, ready to be re-executed.
Any SQL statement variables that had values bound to them using
the <a href="#sqlite3_bind_blob">sqlite3_bind_*() API</a> retain their values.
Use <a href="#sqlite3_clear_bindings">sqlite3_clear_bindings()</a> to reset the bindings.</p>
<p>The <a href="#sqlite3_reset">sqlite3_reset(S)</a> interface resets the <a href="#sqlite3_stmt">prepared statement</a> S
back to the beginning of its program.</p>
<p>The return code from <a href="#sqlite3_reset">sqlite3_reset(S)</a> indicates whether or not
the previous evaluation of prepared statement S completed successfully.
If <a href="#sqlite3_step">sqlite3_step(S)</a> has never before been called on S or if
<a href="#sqlite3_step">sqlite3_step(S)</a> has not been called since the previous call
to <a href="#sqlite3_reset">sqlite3_reset(S)</a>, then <a href="#sqlite3_reset">sqlite3_reset(S)</a> will return
<a href="#SQLITE_ABORT">SQLITE_OK</a>.</p>
<p>If the most recent call to <a href="#sqlite3_step">sqlite3_step(S)</a> for the
<a href="#sqlite3_stmt">prepared statement</a> S indicated an error, then
<a href="#sqlite3_reset">sqlite3_reset(S)</a> returns an appropriate <a href="rescode.html">error code</a>.
The <a href="#sqlite3_reset">sqlite3_reset(S)</a> interface might also return an <a href="rescode.html">error code</a>
if there were no prior errors but the process of resetting
the prepared statement caused a new error. For example, if an
<a href="lang_insert.html">INSERT</a> statement with a <a href="lang_returning.html">RETURNING</a> clause is only stepped one time,
that one call to <a href="#sqlite3_step">sqlite3_step(S)</a> might return SQLITE_ROW but
the overall statement might still fail and the <a href="#sqlite3_reset">sqlite3_reset(S)</a> call
might return SQLITE_BUSY if locking constraints prevent the
database change from committing. Therefore, it is important that
applications check the return code from <a href="#sqlite3_reset">sqlite3_reset(S)</a> even if
no prior call to <a href="#sqlite3_step">sqlite3_step(S)</a> indicated a problem.</p>
<p>The <a href="#sqlite3_reset">sqlite3_reset(S)</a> interface does not change the values
of any <a href="#sqlite3_bind_blob">bindings</a> on the <a href="#sqlite3_stmt">prepared statement</a> S.
</p><hr><a name="sqlite3_reset_auto_extension"></a>
<h2>Reset Automatic Extension Loading</h2>
</div>
<blockquote><pre>
void sqlite3_reset_auto_extension(void);
</pre></blockquote>
<p>
This interface disables all automatic extensions previously
registered using <a href="#sqlite3_auto_extension">sqlite3_auto_extension()</a>.
</p><hr><a name="sqlite3_result_subtype"></a>
<h2>Setting The Subtype Of An SQL Function</h2>
</div>
<blockquote><pre>
void sqlite3_result_subtype(sqlite3_context*,unsigned int);
</pre></blockquote>
<p>
The sqlite3_result_subtype(C,T) function causes the subtype of
the result from the <a href="appfunc.html">application-defined SQL function</a> with
<a href="#sqlite3_context">sqlite3_context</a> C to be the value T. Only the lower 8 bits
of the subtype T are preserved in current versions of SQLite;
higher order bits are discarded.
The number of subtype bytes preserved by SQLite might increase
in future releases of SQLite.</p>
<p>Every <a href="appfunc.html">application-defined SQL function</a> that invokes this interface
should include the <a href="#sqliteresultsubtype">SQLITE_RESULT_SUBTYPE</a> property in its
text encoding argument when the SQL function is
<a href="#sqlite3_create_function">registered</a>. If the <a href="#sqliteresultsubtype">SQLITE_RESULT_SUBTYPE</a>
property is omitted from the function that invokes sqlite3_result_subtype(),
then in some cases the sqlite3_result_subtype() might fail to set
the result subtype.</p>
<p>If SQLite is compiled with -DSQLITE_STRICT_SUBTYPE=1, then any
SQL function that invokes the sqlite3_result_subtype() interface
and that does not have the SQLITE_RESULT_SUBTYPE property will raise
an error. Future versions of SQLite might enable -DSQLITE_STRICT_SUBTYPE=1
by default.
</p><hr><a name="sqlite3_serialize"></a>
<h2>Serialize a database</h2>
</div>
<blockquote><pre>
unsigned char *sqlite3_serialize(
sqlite3 *db, /* The database connection */
const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */
sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */
);
</pre></blockquote>
<p>
The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory
that is a serialization of the S database on <a href="#sqlite3">database connection</a> D.
If P is not a NULL pointer, then the size of the database in bytes
is written into *P.</p>
<p>For an ordinary on-disk database file, the serialization is just a
copy of the disk file. For an in-memory database or a "TEMP" database,
the serialization is the same sequence of bytes which would be written
to disk if that database where backed up to disk.</p>
<p>The usual case is that sqlite3_serialize() copies the serialization of
the database into memory obtained from <a href="#sqlite3_free">sqlite3_malloc64()</a> and returns
a pointer to that memory. The caller is responsible for freeing the
returned value to avoid a memory leak. However, if the F argument
contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
are made, and the sqlite3_serialize() function will return a pointer
to the contiguous memory representation of the database that SQLite
is currently using for that database, or NULL if the no such contiguous
memory representation of the database exists. A contiguous memory
representation of the database will usually only exist if there has
been a prior call to <a href="#sqlite3_deserialize">sqlite3_deserialize(D,S,...)</a> with the same
values of D and S.
The size of the database is written into *P even if the
SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
of the database exists.</p>
<p>After the call, if the SQLITE_SERIALIZE_NOCOPY bit had been set,
the returned buffer content will remain accessible and unchanged
until either the next write operation on the connection or when
the connection is closed, and applications must not modify the
buffer. If the bit had been clear, the returned buffer will not
be accessed by SQLite after the call.</p>
<p>A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
allocation error occurs.</p>
<p>This interface is omitted if SQLite is compiled with the
<a href="compile.html#omit_deserialize">SQLITE_OMIT_DESERIALIZE</a> option.
</p><hr><a name="sqlite3_set_last_insert_rowid"></a>
<h2>Set the Last Insert Rowid value.</h2>
</div>
<blockquote><pre>
void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
</pre></blockquote>
<p>
The sqlite3_set_last_insert_rowid(D, R) method allows the application to
set the value returned by calling sqlite3_last_insert_rowid(D) to R
without inserting a row into the database.
</p><hr><a name="sqlite3_sleep"></a>
<h2>Suspend Execution For A Short Time</h2>
</div>
<blockquote><pre>
int sqlite3_sleep(int);
</pre></blockquote>
<p>
The sqlite3_sleep() function causes the current thread to suspend execution
for at least a number of milliseconds specified in its parameter.</p>
<p>If the operating system does not support sleep requests with
millisecond time resolution, then the time will be rounded up to
the nearest second. The number of milliseconds of sleep actually
requested from the operating system is returned.</p>
<p>SQLite implements this interface by calling the xSleep()
method of the default <a href="#sqlite3_vfs">sqlite3_vfs</a> object. If the xSleep() method
of the default VFS is not implemented correctly, or not implemented at
all, then the behavior of sqlite3_sleep() may deviate from the description
in the previous paragraphs.</p>
<p>If a negative argument is passed to sqlite3_sleep() the results vary by
VFS and operating system. Some system treat a negative argument as an
instruction to sleep forever. Others understand it to mean do not sleep
at all. In SQLite version 3.42.0 and later, a negative
argument passed into sqlite3_sleep() is changed to zero before it is relayed
down into the xSleep method of the VFS.
</p><hr><a name="sqlite3_snapshot_cmp"></a>
<h2>Compare the ages of two snapshot handles.</h2>
</div>
<blockquote><pre>
int sqlite3_snapshot_cmp(
sqlite3_snapshot *p1,
sqlite3_snapshot *p2
);
</pre></blockquote>
<p>
The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
of two valid snapshot handles.</p>
<p>If the two snapshot handles are not associated with the same database
file, the result of the comparison is undefined.</p>
<p>Additionally, the result of the comparison is only valid if both of the
snapshot handles were obtained by calling sqlite3_snapshot_get() since the
last time the wal file was deleted. The wal file is deleted when the
database is changed back to rollback mode or when the number of database
clients drops to zero. If either snapshot handle was obtained before the
wal file was last deleted, the value returned by this function
is undefined.</p>
<p>Otherwise, this API returns a negative value if P1 refers to an older
snapshot than P2, zero if the two handles refer to the same database
snapshot, and a positive value if P1 is a newer snapshot than P2.</p>
<p>This interface is only available if SQLite is compiled with the
<a href="compile.html#enable_snapshot">SQLITE_ENABLE_SNAPSHOT</a> option.
</p><hr><a name="sqlite3_snapshot_free"></a>
<h2>Destroy a snapshot</h2>
</div>
<blockquote><pre>
void sqlite3_snapshot_free(sqlite3_snapshot*);
</pre></blockquote>
<p>
The <a href="#sqlite3_snapshot_free">sqlite3_snapshot_free(P)</a> interface destroys <a href="#sqlite3_snapshot">sqlite3_snapshot</a> P.
The application must eventually free every <a href="#sqlite3_snapshot">sqlite3_snapshot</a> object
using this routine to avoid a memory leak.</p>
<p>The <a href="#sqlite3_snapshot_free">sqlite3_snapshot_free()</a> interface is only available when the
<a href="compile.html#enable_snapshot">SQLITE_ENABLE_SNAPSHOT</a> compile-time option is used.
</p><hr><a name="sqlite3_snapshot_get"></a>
<h2>Record A Database Snapshot</h2>
</div>
<blockquote><pre>
int sqlite3_snapshot_get(
sqlite3 *db,
const char *zSchema,
sqlite3_snapshot **ppSnapshot
);
</pre></blockquote>
<p>
The <a href="#sqlite3_snapshot_get">sqlite3_snapshot_get(D,S,P)</a> interface attempts to make a
new <a href="#sqlite3_snapshot">sqlite3_snapshot</a> object that records the current state of
schema S in database connection D. On success, the
<a href="#sqlite3_snapshot_get">sqlite3_snapshot_get(D,S,P)</a> interface writes a pointer to the newly
created <a href="#sqlite3_snapshot">sqlite3_snapshot</a> object into *P and returns SQLITE_OK.
If there is not already a read-transaction open on schema S when
this function is called, one is opened automatically.</p>
<p>The following must be true for this function to succeed. If any of
the following statements are false when sqlite3_snapshot_get() is
called, SQLITE_ERROR is returned. The final value of *P is undefined
in this case.</p>
<p><ul>
<li> The database handle must not be in <a href="#sqlite3_get_autocommit">autocommit mode</a>.</p>
<p><li> Schema S of <a href="#sqlite3">database connection</a> D must be a <a href="wal.html">WAL mode</a> database.</p>
<p><li> There must not be a write transaction open on schema S of database
connection D.</p>
<p><li> One or more transactions must have been written to the current wal
file since it was created on disk (by any connection). This means
that a snapshot cannot be taken on a wal mode database with no wal
file immediately after it is first opened. At least one transaction
must be written to it first.
</ul></p>
<p>This function may also return SQLITE_NOMEM. If it is called with the
database handle in autocommit mode but fails for some other reason,
whether or not a read transaction is opened on schema S is undefined.</p>
<p>The <a href="#sqlite3_snapshot">sqlite3_snapshot</a> object returned from a successful call to
<a href="#sqlite3_snapshot_get">sqlite3_snapshot_get()</a> must be freed using <a href="#sqlite3_snapshot_free">sqlite3_snapshot_free()</a>
to avoid a memory leak.</p>
<p>The <a href="#sqlite3_snapshot_get">sqlite3_snapshot_get()</a> interface is only available when the
<a href="compile.html#enable_snapshot">SQLITE_ENABLE_SNAPSHOT</a> compile-time option is used.
</p><hr><a name="sqlite3_snapshot_open"></a>
<h2>Start a read transaction on an historical snapshot</h2>
</div>
<blockquote><pre>
int sqlite3_snapshot_open(
sqlite3 *db,
const char *zSchema,
sqlite3_snapshot *pSnapshot
);
</pre></blockquote>
<p>
The <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open(D,S,P)</a> interface either starts a new read
transaction or upgrades an existing one for schema S of
<a href="#sqlite3">database connection</a> D such that the read transaction refers to
historical <a href="#sqlite3_snapshot">snapshot</a> P, rather than the most recent change to the
database. The <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open()</a> interface returns SQLITE_OK
on success or an appropriate <a href="rescode.html">error code</a> if it fails.</p>
<p>In order to succeed, the database connection must not be in
<a href="#sqlite3_get_autocommit">autocommit mode</a> when <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open(D,S,P)</a> is called. If there
is already a read transaction open on schema S, then the database handle
must have no active statements (SELECT statements that have been passed
to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
SQLITE_ERROR is returned if either of these conditions is violated, or
if schema S does not exist, or if the snapshot object is invalid.</p>
<p>A call to sqlite3_snapshot_open() will fail to open if the specified
snapshot has been overwritten by a <a href="wal.html#ckpt">checkpoint</a>. In this case
SQLITE_ERROR_SNAPSHOT is returned.</p>
<p>If there is already a read transaction open when this function is
invoked, then the same read transaction remains open (on the same
database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
is returned. If another error code - for example SQLITE_PROTOCOL or an
SQLITE_IOERR error code - is returned, then the final state of the
read transaction is undefined. If SQLITE_OK is returned, then the
read transaction is now open on database snapshot P.</p>
<p>A call to <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open(D,S,P)</a> will fail if the
database connection D does not know that the database file for
schema S is in <a href="wal.html">WAL mode</a>. A database connection might not know
that the database file is in <a href="wal.html">WAL mode</a> if there has been no prior
I/O on that database connection, or if the database entered <a href="wal.html">WAL mode</a>
after the most recent I/O on the database connection.
(Hint: Run "<a href="pragma.html#pragma_application_id">PRAGMA application_id</a>" against a newly opened
database connection in order to make it ready to use snapshots.)</p>
<p>The <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open()</a> interface is only available when the
<a href="compile.html#enable_snapshot">SQLITE_ENABLE_SNAPSHOT</a> compile-time option is used.
</p><hr><a name="sqlite3_snapshot_recover"></a>
<h2>Recover snapshots from a wal file</h2>
</div>
<blockquote><pre>
int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
</pre></blockquote>
<p>
If a <a href="wal.html#walfile">WAL file</a> remains on disk after all database connections close
(either through the use of the <a href="#sqlitefcntlpersistwal">SQLITE_FCNTL_PERSIST_WAL</a> <a href="#sqlite3_file_control">file control</a>
or because the last process to have the database opened exited without
calling <a href="#sqlite3_close">sqlite3_close()</a>) and a new connection is subsequently opened
on that database and <a href="wal.html#walfile">WAL file</a>, the <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open()</a> interface
will only be able to open the last transaction added to the WAL file
even though the WAL file contains other valid transactions.</p>
<p>This function attempts to scan the WAL file associated with database zDb
of database handle db and make all valid snapshots available to
sqlite3_snapshot_open(). It is an error if there is already a read
transaction open on the database, or if the database is not a WAL mode
database.</p>
<p>SQLITE_OK is returned if successful, or an SQLite error code otherwise.</p>
<p>This interface is only available if SQLite is compiled with the
<a href="compile.html#enable_snapshot">SQLITE_ENABLE_SNAPSHOT</a> option.
</p><hr><a name="sqlite3_soft_heap_limit"></a>
<h2>Deprecated Soft Heap Limit Interface</h2>
</div>
<blockquote><pre>
void sqlite3_soft_heap_limit(int N);
</pre></blockquote>
<p>
This is a deprecated version of the <a href="#sqlite3_hard_heap_limit64">sqlite3_soft_heap_limit64()</a>
interface. This routine is provided for historical compatibility
only. All new applications should use the
<a href="#sqlite3_hard_heap_limit64">sqlite3_soft_heap_limit64()</a> interface rather than this one.
</p><hr><a name="sqlite3_step"></a>
<h2>Evaluate An SQL Statement</h2>
</div>
<blockquote><pre>
int sqlite3_step(sqlite3_stmt*);
</pre></blockquote>
<p>
After a <a href="#sqlite3_stmt">prepared statement</a> has been prepared using any of
<a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>, <a href="#sqlite3_prepare">sqlite3_prepare_v3()</a>, <a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a>,
or <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a> or one of the legacy
interfaces <a href="#sqlite3_prepare">sqlite3_prepare()</a> or <a href="#sqlite3_prepare">sqlite3_prepare16()</a>, this function
must be called one or more times to evaluate the statement.</p>
<p>The details of the behavior of the sqlite3_step() interface depend
on whether the statement was prepared using the newer "vX" interfaces
<a href="#sqlite3_prepare">sqlite3_prepare_v3()</a>, <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>, <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a>,
<a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a> or the older legacy
interfaces <a href="#sqlite3_prepare">sqlite3_prepare()</a> and <a href="#sqlite3_prepare">sqlite3_prepare16()</a>. The use of the
new "vX" interface is recommended for new applications but the legacy
interface will continue to be supported.</p>
<p>In the legacy interface, the return value will be either <a href="#SQLITE_ABORT">SQLITE_BUSY</a>,
<a href="#SQLITE_ABORT">SQLITE_DONE</a>, <a href="#SQLITE_ABORT">SQLITE_ROW</a>, <a href="#SQLITE_ABORT">SQLITE_ERROR</a>, or <a href="#SQLITE_ABORT">SQLITE_MISUSE</a>.
With the "v2" interface, any of the other <a href="rescode.html">result codes</a> or
<a href="rescode.html#extrc">extended result codes</a> might be returned as well.</p>
<p><a href="#SQLITE_ABORT">SQLITE_BUSY</a> means that the database engine was unable to acquire the
database locks it needs to do its job. If the statement is a <a href="lang_transaction.html">COMMIT</a>
or occurs outside of an explicit transaction, then you can retry the
statement. If the statement is not a <a href="lang_transaction.html">COMMIT</a> and occurs within an
explicit transaction then you should rollback the transaction before
continuing.</p>
<p><a href="#SQLITE_ABORT">SQLITE_DONE</a> means that the statement has finished executing
successfully. sqlite3_step() should not be called again on this virtual
machine without first calling <a href="#sqlite3_reset">sqlite3_reset()</a> to reset the virtual
machine back to its initial state.</p>
<p>If the SQL statement being executed returns any data, then <a href="#SQLITE_ABORT">SQLITE_ROW</a>
is returned each time a new row of data is ready for processing by the
caller. The values may be accessed using the <a href="#sqlite3_column_blob">column access functions</a>.
sqlite3_step() is called again to retrieve the next row of data.</p>
<p><a href="#SQLITE_ABORT">SQLITE_ERROR</a> means that a run-time error (such as a constraint
violation) has occurred. sqlite3_step() should not be called again on
the VM. More information may be found by calling <a href="#sqlite3_errcode">sqlite3_errmsg()</a>.
With the legacy interface, a more specific error code (for example,
<a href="#SQLITE_ABORT">SQLITE_INTERRUPT</a>, <a href="#SQLITE_ABORT">SQLITE_SCHEMA</a>, <a href="#SQLITE_ABORT">SQLITE_CORRUPT</a>, and so forth)
can be obtained by calling <a href="#sqlite3_reset">sqlite3_reset()</a> on the
<a href="#sqlite3_stmt">prepared statement</a>. In the "v2" interface,
the more specific error code is returned directly by sqlite3_step().</p>
<p><a href="#SQLITE_ABORT">SQLITE_MISUSE</a> means that the this routine was called inappropriately.
Perhaps it was called on a <a href="#sqlite3_stmt">prepared statement</a> that has
already been <a href="#sqlite3_finalize">finalized</a> or on one that had
previously returned <a href="#SQLITE_ABORT">SQLITE_ERROR</a> or <a href="#SQLITE_ABORT">SQLITE_DONE</a>. Or it could
be the case that the same database connection is being used by two or
more threads at the same moment in time.</p>
<p>For all versions of SQLite up to and including 3.6.23.1, a call to
<a href="#sqlite3_reset">sqlite3_reset()</a> was required after sqlite3_step() returned anything
other than <a href="#SQLITE_ABORT">SQLITE_ROW</a> before any subsequent invocation of
sqlite3_step(). Failure to reset the prepared statement using
<a href="#sqlite3_reset">sqlite3_reset()</a> would result in an <a href="#SQLITE_ABORT">SQLITE_MISUSE</a> return from
sqlite3_step(). But after <a href="releaselog/3_6_23_1.html">version 3.6.23.1</a> (2010-03-26,
sqlite3_step() began
calling <a href="#sqlite3_reset">sqlite3_reset()</a> automatically in this circumstance rather
than returning <a href="#SQLITE_ABORT">SQLITE_MISUSE</a>. This is not considered a compatibility
break because any application that ever receives an SQLITE_MISUSE error
is broken by definition. The <a href="compile.html#omit_autoreset">SQLITE_OMIT_AUTORESET</a> compile-time option
can be used to restore the legacy behavior.</p>
<p><b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
API always returns a generic error code, <a href="#SQLITE_ABORT">SQLITE_ERROR</a>, following any
error other than <a href="#SQLITE_ABORT">SQLITE_BUSY</a> and <a href="#SQLITE_ABORT">SQLITE_MISUSE</a>. You must call
<a href="#sqlite3_reset">sqlite3_reset()</a> or <a href="#sqlite3_finalize">sqlite3_finalize()</a> in order to find one of the
specific <a href="rescode.html">error codes</a> that better describes the error.
We admit that this is a goofy design. The problem has been fixed
with the "v2" interface. If you prepare all of your SQL statements
using <a href="#sqlite3_prepare">sqlite3_prepare_v3()</a> or <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>
or <a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a> or <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a> instead
of the legacy <a href="#sqlite3_prepare">sqlite3_prepare()</a> and <a href="#sqlite3_prepare">sqlite3_prepare16()</a> interfaces,
then the more specific <a href="rescode.html">error codes</a> are returned directly
by sqlite3_step(). The use of the "vX" interfaces is recommended.
</p><hr><a name="sqlite3_stmt_busy"></a>
<h2>Determine If A Prepared Statement Has Been Reset</h2>
</div>
<blockquote><pre>
int sqlite3_stmt_busy(sqlite3_stmt*);
</pre></blockquote>
<p>
The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
<a href="#sqlite3_stmt">prepared statement</a> S has been stepped at least once using
<a href="#sqlite3_step">sqlite3_step(S)</a> but has neither run to completion (returned
<a href="#SQLITE_ABORT">SQLITE_DONE</a> from <a href="#sqlite3_step">sqlite3_step(S)</a>) nor
been reset using <a href="#sqlite3_reset">sqlite3_reset(S)</a>. The sqlite3_stmt_busy(S)
interface returns false if S is a NULL pointer. If S is not a
NULL pointer and is not a pointer to a valid <a href="#sqlite3_stmt">prepared statement</a>
object, then the behavior is undefined and probably undesirable.</p>
<p>This interface can be used in combination <a href="#sqlite3_next_stmt">sqlite3_next_stmt()</a>
to locate all prepared statements associated with a database
connection that are in need of being reset. This can be used,
for example, in diagnostic routines to search for prepared
statements that are holding a transaction open.
</p><hr><a name="sqlite3_stmt_explain"></a>
<h2>Change The EXPLAIN Setting For A Prepared Statement</h2>
</div>
<blockquote><pre>
int sqlite3_stmt_explain(sqlite3_stmt *pStmt, int eMode);
</pre></blockquote>
<p>
The sqlite3_stmt_explain(S,E) interface changes the EXPLAIN
setting for <a href="#sqlite3_stmt">prepared statement</a> S. If E is zero, then S becomes
a normal prepared statement. If E is 1, then S behaves as if
its SQL text began with "<a href="lang_explain.html">EXPLAIN</a>". If E is 2, then S behaves as if
its SQL text began with "<a href="eqp.html">EXPLAIN QUERY PLAN</a>".</p>
<p>Calling sqlite3_stmt_explain(S,E) might cause S to be reprepared.
SQLite tries to avoid a reprepare, but a reprepare might be necessary
on the first transition into EXPLAIN or EXPLAIN QUERY PLAN mode.</p>
<p>Because of the potential need to reprepare, a call to
sqlite3_stmt_explain(S,E) will fail with SQLITE_ERROR if S cannot be
reprepared because it was created using <a href="#sqlite3_prepare">sqlite3_prepare()</a> instead of
the newer <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> or <a href="#sqlite3_prepare">sqlite3_prepare_v3()</a> interfaces and
hence has no saved SQL text with which to reprepare.</p>
<p>Changing the explain setting for a prepared statement does not change
the original SQL text for the statement. Hence, if the SQL text originally
began with EXPLAIN or EXPLAIN QUERY PLAN, but sqlite3_stmt_explain(S,0)
is called to convert the statement into an ordinary statement, the EXPLAIN
or EXPLAIN QUERY PLAN keywords will still appear in the sqlite3_sql(S)
output, even though the statement now acts like a normal SQL statement.</p>
<p>This routine returns SQLITE_OK if the explain mode is successfully
changed, or an error code if the explain mode could not be changed.
The explain mode cannot be changed while a statement is active.
Hence, it is good practice to call <a href="#sqlite3_reset">sqlite3_reset(S)</a>
immediately prior to calling sqlite3_stmt_explain(S,E).
</p><hr><a name="sqlite3_stmt_isexplain"></a>
<h2>Query The EXPLAIN Setting For A Prepared Statement</h2>
</div>
<blockquote><pre>
int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
</pre></blockquote>
<p>
The sqlite3_stmt_isexplain(S) interface returns 1 if the
prepared statement S is an EXPLAIN statement, or 2 if the
statement S is an EXPLAIN QUERY PLAN.
The sqlite3_stmt_isexplain(S) interface returns 0 if S is
an ordinary statement or a NULL pointer.
</p><hr><a name="sqlite3_stmt_readonly"></a>
<h2>Determine If An SQL Statement Writes The Database</h2>
</div>
<blockquote><pre>
int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
</pre></blockquote>
<p>
The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
and only if the <a href="#sqlite3_stmt">prepared statement</a> X makes no direct changes to
the content of the database file.</p>
<p>Note that <a href="appfunc.html">application-defined SQL functions</a> or
<a href="vtab.html">virtual tables</a> might change the database indirectly as a side effect.
For example, if an application defines a function "eval()" that
calls <a href="#sqlite3_exec">sqlite3_exec()</a>, then the following SQL statement would
change the database file through side-effects:</p>
<p><blockquote><pre>
SELECT eval('DELETE FROM t1') FROM t2;
</pre></blockquote></p>
<p>But because the <a href="lang_select.html">SELECT</a> statement does not change the database file
directly, sqlite3_stmt_readonly() would still return true.</p>
<p>Transaction control statements such as <a href="lang_transaction.html">BEGIN</a>, <a href="lang_transaction.html">COMMIT</a>, <a href="lang_transaction.html">ROLLBACK</a>,
<a href="lang_savepoint.html">SAVEPOINT</a>, and <a href="lang_savepoint.html">RELEASE</a> cause sqlite3_stmt_readonly() to return true,
since the statements themselves do not actually modify the database but
rather they control the timing of when other statements modify the
database. The <a href="lang_attach.html">ATTACH</a> and <a href="lang_detach.html">DETACH</a> statements also cause
sqlite3_stmt_readonly() to return true since, while those statements
change the configuration of a database connection, they do not make
changes to the content of the database files on disk.
The sqlite3_stmt_readonly() interface returns true for <a href="lang_transaction.html">BEGIN</a> since
<a href="lang_transaction.html">BEGIN</a> merely sets internal flags, but the <a href="lang_transaction.html">BEGIN IMMEDIATE</a> and
<a href="lang_transaction.html">BEGIN EXCLUSIVE</a> commands do touch the database and so
sqlite3_stmt_readonly() returns false for those commands.</p>
<p>This routine returns false if there is any possibility that the
statement might change the database file. A false return does
not guarantee that the statement will change the database file.
For example, an UPDATE statement might have a WHERE clause that
makes it a no-op, but the sqlite3_stmt_readonly() result would still
be false. Similarly, a CREATE TABLE IF NOT EXISTS statement is a
read-only no-op if the table already exists, but
sqlite3_stmt_readonly() still returns false for such a statement.</p>
<p>If prepared statement X is an <a href="lang_explain.html">EXPLAIN</a> or <a href="eqp.html">EXPLAIN QUERY PLAN</a>
statement, then sqlite3_stmt_readonly(X) returns the same value as
if the EXPLAIN or EXPLAIN QUERY PLAN prefix were omitted.
</p><hr><a name="sqlite3_stmt_scanstatus_reset"></a>
<h2>Zero Scan-Status Counters</h2>
</div>
<blockquote><pre>
void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
</pre></blockquote>
<p>
Zero all <a href="#sqlite3_stmt_scanstatus">sqlite3_stmt_scanstatus()</a> related event counters.</p>
<p>This API is only available if the library is built with pre-processor
symbol <a href="compile.html#enable_stmt_scanstatus">SQLITE_ENABLE_STMT_SCANSTATUS</a> defined.
</p><hr><a name="sqlite3_stmt_status"></a>
<h2>Prepared Statement Status</h2>
</div>
<blockquote><pre>
int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
</pre></blockquote>
<p>
Each prepared statement maintains various
<a href="#SQLITE_STMTSTATUS counter">SQLITE_STMTSTATUS counters</a> that measure the number
of times it has performed specific operations. These counters can
be used to monitor the performance characteristics of the prepared
statements. For example, if the number of table steps greatly exceeds
the number of table searches or result rows, that would tend to indicate
that the prepared statement is using a full table scan rather than
an index.</p>
<p>This interface is used to retrieve and reset counter values from
a <a href="#sqlite3_stmt">prepared statement</a>. The first argument is the prepared statement
object to be interrogated. The second argument
is an integer code for a specific <a href="#SQLITE_STMTSTATUS counter">SQLITE_STMTSTATUS counter</a>
to be interrogated.
The current value of the requested counter is returned.
If the resetFlg is true, then the counter is reset to zero after this
interface call returns.</p>
<p>See also: <a href="#sqlite3_status">sqlite3_status()</a> and <a href="#sqlite3_db_status">sqlite3_db_status()</a>.
</p><hr><a name="sqlite3_str_finish"></a>
<h2>Finalize A Dynamic String</h2>
</div>
<blockquote><pre>
char *sqlite3_str_finish(sqlite3_str*);
</pre></blockquote>
<p>
The <a href="#sqlite3_str_finish">sqlite3_str_finish(X)</a> interface destroys the sqlite3_str object X
and returns a pointer to a memory buffer obtained from <a href="#sqlite3_free">sqlite3_malloc64()</a>
that contains the constructed string. The calling application should
pass the returned value to <a href="#sqlite3_free">sqlite3_free()</a> to avoid a memory leak.
The <a href="#sqlite3_str_finish">sqlite3_str_finish(X)</a> interface may return a NULL pointer if any
errors were encountered during construction of the string. The
<a href="#sqlite3_str_finish">sqlite3_str_finish(X)</a> interface will also return a NULL pointer if the
string in <a href="#sqlite3_str">sqlite3_str</a> object X is zero bytes long.
</p><hr><a name="sqlite3_str_new"></a>
<h2>Create A New Dynamic String Object</h2>
</div>
<blockquote><pre>
sqlite3_str *sqlite3_str_new(sqlite3*);
</pre></blockquote>
<p>
The <a href="#sqlite3_str_new">sqlite3_str_new(D)</a> interface allocates and initializes
a new <a href="#sqlite3_str">sqlite3_str</a> object. To avoid memory leaks, the object returned by
<a href="#sqlite3_str_new">sqlite3_str_new()</a> must be freed by a subsequent call to
<a href="#sqlite3_str_finish">sqlite3_str_finish(X)</a>.</p>
<p>The <a href="#sqlite3_str_new">sqlite3_str_new(D)</a> interface always returns a pointer to a
valid <a href="#sqlite3_str">sqlite3_str</a> object, though in the event of an out-of-memory
error the returned object might be a special singleton that will
silently reject new text, always return SQLITE_NOMEM from
<a href="#sqlite3_str_errcode">sqlite3_str_errcode()</a>, always return 0 for
<a href="#sqlite3_str_errcode">sqlite3_str_length()</a>, and always return NULL from
<a href="#sqlite3_str_finish">sqlite3_str_finish(X)</a>. It is always safe to use the value
returned by <a href="#sqlite3_str_new">sqlite3_str_new(D)</a> as the sqlite3_str parameter
to any of the other <a href="#sqlite3_str">sqlite3_str</a> methods.</p>
<p>The D parameter to <a href="#sqlite3_str_new">sqlite3_str_new(D)</a> may be NULL. If the
D parameter in <a href="#sqlite3_str_new">sqlite3_str_new(D)</a> is not NULL, then the maximum
length of the string contained in the <a href="#sqlite3_str">sqlite3_str</a> object will be
the value set for <a href="#sqlite3_limit">sqlite3_limit</a>(D,<a href="#sqlitelimitlength">SQLITE_LIMIT_LENGTH</a>) instead
of <a href="limits.html#max_length">SQLITE_MAX_LENGTH</a>.
</p><hr><a name="sqlite3_strglob"></a>
<h2>String Globbing</h2>
</div>
<blockquote><pre>
int sqlite3_strglob(const char *zGlob, const char *zStr);
</pre></blockquote>
<p>The <a href="#sqlite3_strglob">sqlite3_strglob(P,X)</a> interface returns zero if and only if
string X matches the <a href="lang_expr.html#glob">GLOB</a> pattern P.
The definition of <a href="lang_expr.html#glob">GLOB</a> pattern matching used in
<a href="#sqlite3_strglob">sqlite3_strglob(P,X)</a> is the same as for the "X GLOB P" operator in the
SQL dialect understood by SQLite. The <a href="#sqlite3_strglob">sqlite3_strglob(P,X)</a> function
is case sensitive.</p>
<p>Note that this routine returns zero on a match and non-zero if the strings
do not match, the same as <a href="#sqlite3_stricmp">sqlite3_stricmp()</a> and <a href="#sqlite3_stricmp">sqlite3_strnicmp()</a>.</p>
<p>See also: <a href="#sqlite3_strlike">sqlite3_strlike()</a>.
</p><hr><a name="sqlite3_strlike"></a>
<h2>String LIKE Matching</h2>
</div>
<blockquote><pre>
int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
</pre></blockquote>
<p>The <a href="#sqlite3_strlike">sqlite3_strlike(P,X,E)</a> interface returns zero if and only if
string X matches the <a href="lang_expr.html#like">LIKE</a> pattern P with escape character E.
The definition of <a href="lang_expr.html#like">LIKE</a> pattern matching used in
<a href="#sqlite3_strlike">sqlite3_strlike(P,X,E)</a> is the same as for the "X LIKE P ESCAPE E"
operator in the SQL dialect understood by SQLite. For "X LIKE P" without
the ESCAPE clause, set the E parameter of <a href="#sqlite3_strlike">sqlite3_strlike(P,X,E)</a> to 0.
As with the LIKE operator, the <a href="#sqlite3_strlike">sqlite3_strlike(P,X,E)</a> function is case
insensitive - equivalent upper and lower case ASCII characters match
one another.</p>
<p>The <a href="#sqlite3_strlike">sqlite3_strlike(P,X,E)</a> function matches Unicode characters, though
only ASCII characters are case folded.</p>
<p>Note that this routine returns zero on a match and non-zero if the strings
do not match, the same as <a href="#sqlite3_stricmp">sqlite3_stricmp()</a> and <a href="#sqlite3_stricmp">sqlite3_strnicmp()</a>.</p>
<p>See also: <a href="#sqlite3_strglob">sqlite3_strglob()</a>.
</p><hr><a name="sqlite3_system_errno"></a>
<h2>Low-level system error code</h2>
</div>
<blockquote><pre>
int sqlite3_system_errno(sqlite3*);
</pre></blockquote>
<p>
Attempt to return the underlying operating system error code or error
number that caused the most recent I/O error or failure to open a file.
The return value is OS-dependent. For example, on unix systems, after
<a href="#sqlite3_open">sqlite3_open_v2()</a> returns <a href="#SQLITE_ABORT">SQLITE_CANTOPEN</a>, this interface could be
called to get back the underlying "errno" that caused the problem, such
as ENOSPC, EAUTH, EISDIR, and so forth.
</p><hr><a name="sqlite3_table_column_metadata"></a>
<h2>Extract Metadata About A Column Of A Table</h2>
</div>
<blockquote><pre>
int sqlite3_table_column_metadata(
sqlite3 *db, /* Connection handle */
const char *zDbName, /* Database name or NULL */
const char *zTableName, /* Table name */
const char *zColumnName, /* Column name */
char const **pzDataType, /* OUTPUT: Declared data type */
char const **pzCollSeq, /* OUTPUT: Collation sequence name */
int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
int *pPrimaryKey, /* OUTPUT: True if column part of PK */
int *pAutoinc /* OUTPUT: True if column is auto-increment */
);
</pre></blockquote>
<p>
The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
information about column C of table T in database D
on <a href="#sqlite3">database connection</a> X. The sqlite3_table_column_metadata()
interface returns SQLITE_OK and fills in the non-NULL pointers in
the final five arguments with appropriate values if the specified
column exists. The sqlite3_table_column_metadata() interface returns
SQLITE_ERROR if the specified column does not exist.
If the column-name parameter to sqlite3_table_column_metadata() is a
NULL pointer, then this routine simply checks for the existence of the
table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
does not. If the table name parameter T in a call to
sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
undefined behavior.</p>
<p>The column is identified by the second, third and fourth parameters to
this function. The second parameter is either the name of the database
(i.e. "main", "temp", or an attached database) containing the specified
table or NULL. If it is NULL, then all attached databases are searched
for the table using the same algorithm used by the database engine to
resolve unqualified table references.</p>
<p>The third and fourth parameters to this function are the table and column
name of the desired column, respectively.</p>
<p>Metadata is returned by writing to the memory locations passed as the 5th
and subsequent parameters to this function. Any of these arguments may be
NULL, in which case the corresponding element of metadata is omitted.</p>
<p><blockquote>
<table border="1">
<tr><th> Parameter <th> Output<br>Type <th> Description</p>
<p><tr><td> 5th <td> const char* <td> Data type
<tr><td> 6th <td> const char* <td> Name of default collation sequence
<tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
<tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
<tr><td> 9th <td> int <td> True if column is <a href="autoinc.html">AUTOINCREMENT</a>
</table>
</blockquote></p>
<p>The memory pointed to by the character pointers returned for the
declaration type and collation sequence is valid until the next
call to any SQLite API function.</p>
<p>If the specified table is actually a view, an <a href="rescode.html">error code</a> is returned.</p>
<p>If the specified column is "rowid", "oid" or "_rowid_" and the table
is not a <a href="withoutrowid.html">WITHOUT ROWID</a> table and an
<a href="lang_createtable.html#rowid">INTEGER PRIMARY KEY</a> column has been explicitly declared, then the output
parameters are set for the explicitly declared column. If there is no
<a href="lang_createtable.html#rowid">INTEGER PRIMARY KEY</a> column, then the outputs
for the <a href="lang_createtable.html#rowid">rowid</a> are set as follows:</p>
<p><pre>
data type: "INTEGER"
collation sequence: "BINARY"
not null: 0
primary key: 1
auto increment: 0
</pre></p>
<p>This function causes all database schemas to be read from disk and
parsed, if that has not already been done, and returns an error if
any errors are encountered while loading the schema.
</p><hr><a name="sqlite3_test_control"></a>
<h2>Testing Interface</h2>
</div>
<blockquote><pre>
int sqlite3_test_control(int op, ...);
</pre></blockquote>
<p>
The sqlite3_test_control() interface is used to read out internal
state of SQLite and to inject faults into SQLite for testing
purposes. The first parameter is an operation code that determines
the number, meaning, and operation of all subsequent parameters.</p>
<p>This interface is not for use by applications. It exists solely
for verifying the correct operation of the SQLite library. Depending
on how the SQLite library is compiled, this interface might not exist.</p>
<p>The details of the operation codes, their meanings, the parameters
they take, and what they do are all subject to change without notice.
Unlike most of the SQLite API, this function is not guaranteed to
operate consistently from one release to the next.
</p><hr><a name="sqlite3_threadsafe"></a>
<h2>Test To See If The Library Is Threadsafe</h2>
</div>
<blockquote><pre>
int sqlite3_threadsafe(void);
</pre></blockquote>
<p>
The sqlite3_threadsafe() function returns zero if and only if
SQLite was compiled with mutexing code omitted due to the
<a href="compile.html#threadsafe">SQLITE_THREADSAFE</a> compile-time option being set to 0.</p>
<p>SQLite can be compiled with or without mutexes. When
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE</a> C preprocessor macro is 1 or 2, mutexes
are enabled and SQLite is threadsafe. When the
<a href="compile.html#threadsafe">SQLITE_THREADSAFE</a> macro is 0,
the mutexes are omitted. Without the mutexes, it is not safe
to use SQLite concurrently from more than one thread.</p>
<p>Enabling mutexes incurs a measurable performance penalty.
So if speed is of utmost importance, it makes sense to disable
the mutexes. But for maximum safety, mutexes should be enabled.
The default behavior is for mutexes to be enabled.</p>
<p>This interface can be used by an application to make sure that the
version of SQLite that it is linking against was compiled with
the desired setting of the <a href="compile.html#threadsafe">SQLITE_THREADSAFE</a> macro.</p>
<p>This interface only reports on the compile-time mutex setting
of the <a href="compile.html#threadsafe">SQLITE_THREADSAFE</a> flag. If SQLite is compiled with
SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
can be fully or partially disabled using a call to <a href="#sqlite3_config">sqlite3_config()</a>
with the verbs <a href="#sqliteconfigsinglethread">SQLITE_CONFIG_SINGLETHREAD</a>, <a href="#sqliteconfigmultithread">SQLITE_CONFIG_MULTITHREAD</a>,
or <a href="#sqliteconfigserialized">SQLITE_CONFIG_SERIALIZED</a>. The return value of the
sqlite3_threadsafe() function shows only the compile-time setting of
thread safety, not any run-time changes to that setting made by
sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
is unchanged by calls to sqlite3_config().</p>
<p>See the <a href="threadsafe.html">threading mode</a> documentation for additional information.
</p><hr><a name="sqlite3_trace_v2"></a>
<h2>SQL Trace Hook</h2>
</div>
<blockquote><pre>
int sqlite3_trace_v2(
sqlite3*,
unsigned uMask,
int(*xCallback)(unsigned,void*,void*,void*),
void *pCtx
);
</pre></blockquote>
<p>
The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
function X against <a href="#sqlite3">database connection</a> D, using property mask M
and context pointer P. If the X callback is
NULL or if the M mask is zero, then tracing is disabled. The
M argument should be the bitwise OR-ed combination of
zero or more <a href="#SQLITE_TRACE">SQLITE_TRACE</a> constants.</p>
<p>Each call to either sqlite3_trace(D,X,P) or sqlite3_trace_v2(D,M,X,P)
overrides (cancels) all prior calls to sqlite3_trace(D,X,P) or
sqlite3_trace_v2(D,M,X,P) for the <a href="#sqlite3">database connection</a> D. Each
database connection may have at most one trace callback.</p>
<p>The X callback is invoked whenever any of the events identified by
mask M occur. The integer return value from the callback is currently
ignored, though this may change in future releases. Callback
implementations should return zero to ensure future compatibility.</p>
<p>A trace callback is invoked with four arguments: callback(T,C,P,X).
The T argument is one of the <a href="#SQLITE_TRACE">SQLITE_TRACE</a>
constants to indicate why the callback was invoked.
The C argument is a copy of the context pointer.
The P and X arguments are pointers whose meanings depend on T.</p>
<p>The sqlite3_trace_v2() interface is intended to replace the legacy
interfaces <a href="#sqlite3_profile">sqlite3_trace()</a> and <a href="#sqlite3_profile">sqlite3_profile()</a>, both of which
are deprecated.
</p><hr><a name="sqlite3_txn_state"></a>
<h2>Determine the transaction state of a database</h2>
</div>
<blockquote><pre>
int sqlite3_txn_state(sqlite3*,const char *zSchema);
</pre></blockquote>
<p>
The sqlite3_txn_state(D,S) interface returns the current
<a href="#SQLITE_TXN_NONE">transaction state</a> of schema S in database connection D. If S is NULL,
then the highest transaction state of any schema on database connection D
is returned. Transaction states are (in order of lowest to highest):
<ol>
<li value="0"> SQLITE_TXN_NONE
<li value="1"> SQLITE_TXN_READ
<li value="2"> SQLITE_TXN_WRITE
</ol>
If the S argument to sqlite3_txn_state(D,S) is not the name of
a valid schema, then -1 is returned.
</p><hr><a name="sqlite3_unlock_notify"></a>
<h2>Unlock Notification</h2>
</div>
<blockquote><pre>
int sqlite3_unlock_notify(
sqlite3 *pBlocked, /* Waiting connection */
void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
void *pNotifyArg /* Argument to pass to xNotify */
);
</pre></blockquote>
<p>
When running in shared-cache mode, a database operation may fail with
an <a href="#SQLITE_ABORT">SQLITE_LOCKED</a> error if the required locks on the shared-cache or
individual tables within the shared-cache cannot be obtained. See
<a href="sharedcache.html">SQLite Shared-Cache Mode</a> for a description of shared-cache locking.
This API may be used to register a callback that SQLite will invoke
when the connection currently holding the required lock relinquishes it.
This API is only available if the library was compiled with the
<a href="compile.html#enable_unlock_notify">SQLITE_ENABLE_UNLOCK_NOTIFY</a> C-preprocessor symbol defined.</p>
<p>See Also: <a href="unlock_notify.html">Using the SQLite Unlock Notification Feature</a>.</p>
<p>Shared-cache locks are released when a database connection concludes
its current transaction, either by committing it or rolling it back.</p>
<p>When a connection (known as the blocked connection) fails to obtain a
shared-cache lock and SQLITE_LOCKED is returned to the caller, the
identity of the database connection (the blocking connection) that
has locked the required resource is stored internally. After an
application receives an SQLITE_LOCKED error, it may call the
sqlite3_unlock_notify() method with the blocked connection handle as
the first argument to register for a callback that will be invoked
when the blocking connections current transaction is concluded. The
callback is invoked from within the <a href="#sqlite3_step">sqlite3_step</a> or <a href="#sqlite3_close">sqlite3_close</a>
call that concludes the blocking connection's transaction.</p>
<p>If sqlite3_unlock_notify() is called in a multi-threaded application,
there is a chance that the blocking connection will have already
concluded its transaction by the time sqlite3_unlock_notify() is invoked.
If this happens, then the specified callback is invoked immediately,
from within the call to sqlite3_unlock_notify().</p>
<p>If the blocked connection is attempting to obtain a write-lock on a
shared-cache table, and more than one other connection currently holds
a read-lock on the same table, then SQLite arbitrarily selects one of
the other connections to use as the blocking connection.</p>
<p>There may be at most one unlock-notify callback registered by a
blocked connection. If sqlite3_unlock_notify() is called when the
blocked connection already has a registered unlock-notify callback,
then the new callback replaces the old. If sqlite3_unlock_notify() is
called with a NULL pointer as its second argument, then any existing
unlock-notify callback is canceled. The blocked connections
unlock-notify callback may also be canceled by closing the blocked
connection using <a href="#sqlite3_close">sqlite3_close()</a>.</p>
<p>The unlock-notify callback is not reentrant. If an application invokes
any sqlite3_xxx API functions from within an unlock-notify callback, a
crash or deadlock may be the result.</p>
<p>Unless deadlock is detected (see below), sqlite3_unlock_notify() always
returns SQLITE_OK.</p>
<p><b>Callback Invocation Details</b></p>
<p>When an unlock-notify callback is registered, the application provides a
single void* pointer that is passed to the callback when it is invoked.
However, the signature of the callback function allows SQLite to pass
it an array of void* context pointers. The first argument passed to
an unlock-notify callback is a pointer to an array of void* pointers,
and the second is the number of entries in the array.</p>
<p>When a blocking connection's transaction is concluded, there may be
more than one blocked connection that has registered for an unlock-notify
callback. If two or more such blocked connections have specified the
same callback function, then instead of invoking the callback function
multiple times, it is invoked once with the set of void* context pointers
specified by the blocked connections bundled together into an array.
This gives the application an opportunity to prioritize any actions
related to the set of unblocked database connections.</p>
<p><b>Deadlock Detection</b></p>
<p>Assuming that after registering for an unlock-notify callback a
database waits for the callback to be issued before taking any further
action (a reasonable assumption), then using this API may cause the
application to deadlock. For example, if connection X is waiting for
connection Y's transaction to be concluded, and similarly connection
Y is waiting on connection X's transaction, then neither connection
will proceed and the system may remain deadlocked indefinitely.</p>
<p>To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
detection. If a given call to sqlite3_unlock_notify() would put the
system in a deadlocked state, then SQLITE_LOCKED is returned and no
unlock-notify callback is registered. The system is said to be in
a deadlocked state if connection A has registered for an unlock-notify
callback on the conclusion of connection B's transaction, and connection
B has itself registered for an unlock-notify callback when connection
A's transaction is concluded. Indirect deadlock is also detected, so
the system is also considered to be deadlocked if connection B has
registered for an unlock-notify callback on the conclusion of connection
C's transaction, where connection C is waiting on connection A. Any
number of levels of indirection are allowed.</p>
<p><b>The "DROP TABLE" Exception</b></p>
<p>When a call to <a href="#sqlite3_step">sqlite3_step()</a> returns SQLITE_LOCKED, it is almost
always appropriate to call sqlite3_unlock_notify(). There is however,
one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
SQLite checks if there are any currently executing SELECT statements
that belong to the same connection. If there are, SQLITE_LOCKED is
returned. In this case there is no "blocking connection", so invoking
sqlite3_unlock_notify() results in the unlock-notify callback being
invoked immediately. If the application then re-attempts the "DROP TABLE"
or "DROP INDEX" query, an infinite loop might be the result.</p>
<p>One way around this problem is to check the extended error code returned
by an sqlite3_step() call. If there is a blocking connection, then the
extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
the special "DROP TABLE/INDEX" case, the extended error code is just
SQLITE_LOCKED.
</p><hr><a name="sqlite3_update_hook"></a>
<h2>Data Change Notification Callbacks</h2>
</div>
<blockquote><pre>
void *sqlite3_update_hook(
sqlite3*,
void(*)(void *,int ,char const *,char const *,sqlite3_int64),
void*
);
</pre></blockquote>
<p>
The sqlite3_update_hook() interface registers a callback function
with the <a href="#sqlite3">database connection</a> identified by the first argument
to be invoked whenever a row is updated, inserted or deleted in
a <a href="rowidtable.html">rowid table</a>.
Any callback set by a previous call to this function
for the same database connection is overridden.</p>
<p>The second argument is a pointer to the function to invoke when a
row is updated, inserted or deleted in a rowid table.
The first argument to the callback is a copy of the third argument
to sqlite3_update_hook().
The second callback argument is one of <a href="#SQLITE_ALTER_TABLE">SQLITE_INSERT</a>, <a href="#SQLITE_ALTER_TABLE">SQLITE_DELETE</a>,
or <a href="#SQLITE_ALTER_TABLE">SQLITE_UPDATE</a>, depending on the operation that caused the callback
to be invoked.
The third and fourth arguments to the callback contain pointers to the
database and table name containing the affected row.
The final callback parameter is the <a href="lang_createtable.html#rowid">rowid</a> of the row.
In the case of an update, this is the <a href="lang_createtable.html#rowid">rowid</a> after the update takes place.</p>
<p>The update hook is not invoked when internal system tables are
modified (i.e. sqlite_sequence).
The update hook is not invoked when <a href="withoutrowid.html">WITHOUT ROWID</a> tables are modified.</p>
<p>In the current implementation, the update hook
is not invoked when conflicting rows are deleted because of an
<a href="lang_conflict.html">ON CONFLICT REPLACE</a> clause. Nor is the update hook
invoked when rows are deleted using the <a href="lang_delete.html#truncateopt">truncate optimization</a>.
The exceptions defined in this paragraph might change in a future
release of SQLite.</p>
<p>Whether the update hook is invoked before or after the
corresponding change is currently unspecified and may differ
depending on the type of change. Do not rely on the order of the
hook call with regards to the final result of the operation which
triggers the hook.</p>
<p>The update hook implementation must not do anything that will modify
the database connection that invoked the update hook. Any actions
to modify the database connection must be deferred until after the
completion of the <a href="#sqlite3_step">sqlite3_step()</a> call that triggered the update hook.
Note that <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> and <a href="#sqlite3_step">sqlite3_step()</a> both modify their
database connections for the meaning of "modify" in this paragraph.</p>
<p>The sqlite3_update_hook(D,C,P) function
returns the P argument from the previous call
on the same <a href="#sqlite3">database connection</a> D, or NULL for
the first call on D.</p>
<p>See also the <a href="#sqlite3_commit_hook">sqlite3_commit_hook()</a>, <a href="#sqlite3_commit_hook">sqlite3_rollback_hook()</a>,
and <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_hook()</a> interfaces.
</p><hr><a name="sqlite3_user_data"></a>
<h2>User Data For Functions</h2>
</div>
<blockquote><pre>
void *sqlite3_user_data(sqlite3_context*);
</pre></blockquote>
<p>
The sqlite3_user_data() interface returns a copy of
the pointer that was the pUserData parameter (the 5th parameter)
of the <a href="#sqlite3_create_function">sqlite3_create_function()</a>
and <a href="#sqlite3_create_function">sqlite3_create_function16()</a> routines that originally
registered the application defined function.</p>
<p>This routine must be called from the same thread in which
the application-defined function is running.
</p><hr><a name="sqlite3_value_encoding"></a>
<h2>Report the internal text encoding state of an sqlite3_value object</h2>
</div>
<blockquote><pre>
int sqlite3_value_encoding(sqlite3_value*);
</pre></blockquote>
<p>
The sqlite3_value_encoding(X) interface returns one of <a href="#SQLITE_ANY">SQLITE_UTF8</a>,
<a href="#SQLITE_ANY">SQLITE_UTF16BE</a>, or <a href="#SQLITE_ANY">SQLITE_UTF16LE</a> according to the current text encoding
of the value X, assuming that X has type TEXT. If sqlite3_value_type(X)
returns something other than SQLITE_TEXT, then the return value from
sqlite3_value_encoding(X) is meaningless. Calls to
<a href="#sqlite3_value_blob">sqlite3_value_text(X)</a>, <a href="#sqlite3_value_blob">sqlite3_value_text16(X)</a>, <a href="#sqlite3_value_blob">sqlite3_value_text16be(X)</a>,
<a href="#sqlite3_value_blob">sqlite3_value_text16le(X)</a>, <a href="#sqlite3_value_blob">sqlite3_value_bytes(X)</a>, or
<a href="#sqlite3_value_blob">sqlite3_value_bytes16(X)</a> might change the encoding of the value X and
thus change the return from subsequent calls to sqlite3_value_encoding(X).</p>
<p>This routine is intended for used by applications that test and validate
the SQLite implementation. This routine is inquiring about the opaque
internal state of an <a href="#sqlite3_value">sqlite3_value</a> object. Ordinary applications should
not need to know what the internal state of an sqlite3_value object is and
hence should not need to use this interface.
</p><hr><a name="sqlite3_value_subtype"></a>
<h2>Finding The Subtype Of SQL Values</h2>
</div>
<blockquote><pre>
unsigned int sqlite3_value_subtype(sqlite3_value*);
</pre></blockquote>
<p>
The sqlite3_value_subtype(V) function returns the subtype for
an <a href="appfunc.html">application-defined SQL function</a> argument V. The subtype
information can be used to pass a limited amount of context from
one SQL function to another. Use the <a href="#sqlite3_result_subtype">sqlite3_result_subtype()</a>
routine to set the subtype for the return value of an SQL function.</p>
<p>Every <a href="appfunc.html">application-defined SQL function</a> that invoke this interface
should include the <a href="#sqlitesubtype">SQLITE_SUBTYPE</a> property in the text
encoding argument when the function is <a href="#sqlite3_create_function">registered</a>.
If the <a href="#sqlitesubtype">SQLITE_SUBTYPE</a> property is omitted, then sqlite3_value_subtype()
might return zero instead of the upstream subtype in some corner cases.
</p><hr><a name="sqlite3_vtab_collation"></a>
<h2>Determine The Collation For a Virtual Table Constraint</h2>
</div>
<blockquote><pre>
const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
</pre></blockquote>
<p>
This function may only be called from within a call to the <a href="vtab.html#xbestindex">xBestIndex</a>
method of a <a href="vtab.html">virtual table</a>. This function returns a pointer to a string
that is the name of the appropriate collation sequence to use for text
comparisons on the constraint identified by its arguments.</p>
<p>The first argument must be the pointer to the <a href="#sqlite3_index_info">sqlite3_index_info</a> object
that is the first parameter to the xBestIndex() method. The second argument
must be an index into the aConstraint[] array belonging to the
sqlite3_index_info structure passed to xBestIndex.</p>
<p>Important:
The first parameter must be the same pointer that is passed into the
xBestMethod() method. The first parameter may not be a pointer to a
different <a href="#sqlite3_index_info">sqlite3_index_info</a> object, even an exact copy.</p>
<p>The return value is computed as follows:</p>
<p><ol>
<li><p> If the constraint comes from a WHERE clause expression that contains
a <a href="lang_expr.html#collateop">COLLATE operator</a>, then the name of the collation specified by
that COLLATE operator is returned.
<li><p> If there is no COLLATE operator, but the column that is the subject
of the constraint specifies an alternative collating sequence via
a <a href="lang_createtable.html#collateclause">COLLATE clause</a> on the column definition within the CREATE TABLE
statement that was passed into <a href="#sqlite3_declare_vtab">sqlite3_declare_vtab()</a>, then the
name of that alternative collating sequence is returned.
<li><p> Otherwise, "BINARY" is returned.
</ol>
</p><hr><a name="sqlite3_vtab_config"></a>
<h2>Virtual Table Interface Configuration</h2>
</div>
<blockquote><pre>
int sqlite3_vtab_config(sqlite3*, int op, ...);
</pre></blockquote>
<p>
This function may be called by either the <a href="vtab.html#xconnect">xConnect</a> or <a href="vtab.html#xcreate">xCreate</a> method
of a <a href="vtab.html">virtual table</a> implementation to configure
various facets of the virtual table interface.</p>
<p>If this interface is invoked outside the context of an xConnect or
xCreate virtual table method then the behavior is undefined.</p>
<p>In the call sqlite3_vtab_config(D,C,...) the D parameter is the
<a href="#sqlite3">database connection</a> in which the virtual table is being created and
which is passed in as the first argument to the <a href="vtab.html#xconnect">xConnect</a> or <a href="vtab.html#xcreate">xCreate</a>
method that is invoking sqlite3_vtab_config(). The C parameter is one
of the <a href="#SQLITE_VTAB_CONSTRAINT_SUPPORT">virtual table configuration options</a>. The presence and meaning
of parameters after C depend on which <a href="#SQLITE_VTAB_CONSTRAINT_SUPPORT">virtual table configuration option</a>
is used.
</p><hr><a name="sqlite3_vtab_distinct"></a>
<h2>Determine if a virtual table query is DISTINCT</h2>
</div>
<blockquote><pre>
int sqlite3_vtab_distinct(sqlite3_index_info*);
</pre></blockquote>
<p>
This API may only be used from within an <a href="vtab.html#xbestindex">xBestIndex method</a>
of a <a href="vtab.html">virtual table</a> implementation. The result of calling this
interface from outside of xBestIndex() is undefined and probably harmful.</p>
<p>The sqlite3_vtab_distinct() interface returns an integer between 0 and
3. The integer returned by sqlite3_vtab_distinct()
gives the virtual table additional information about how the query
planner wants the output to be ordered. As long as the virtual table
can meet the ordering requirements of the query planner, it may set
the "orderByConsumed" flag.</p>
<p><ol><li value="0"><p>
If the sqlite3_vtab_distinct() interface returns 0, that means
that the query planner needs the virtual table to return all rows in the
sort order defined by the "nOrderBy" and "aOrderBy" fields of the
<a href="#sqlite3_index_info">sqlite3_index_info</a> object. This is the default expectation. If the
virtual table outputs all rows in sorted order, then it is always safe for
the xBestIndex method to set the "orderByConsumed" flag, regardless of
the return value from sqlite3_vtab_distinct().
<li value="1"><p>
If the sqlite3_vtab_distinct() interface returns 1, that means
that the query planner does not need the rows to be returned in sorted order
as long as all rows with the same values in all columns identified by the
"aOrderBy" field are adjacent. This mode is used when the query planner
is doing a GROUP BY.
<li value="2"><p>
If the sqlite3_vtab_distinct() interface returns 2, that means
that the query planner does not need the rows returned in any particular
order, as long as rows with the same values in all columns identified
by "aOrderBy" are adjacent. Furthermore, when two or more rows
contain the same values for all columns identified by "colUsed", all but
one such row may optionally be omitted from the result.
The virtual table is not required to omit rows that are duplicates
over the "colUsed" columns, but if the virtual table can do that without
too much extra effort, it could potentially help the query to run faster.
This mode is used for a DISTINCT query.
<li value="3"><p>
If the sqlite3_vtab_distinct() interface returns 3, that means the
virtual table must return rows in the order defined by "aOrderBy" as
if the sqlite3_vtab_distinct() interface had returned 0. However if
two or more rows in the result have the same values for all columns
identified by "colUsed", then all but one such row may optionally be
omitted. Like when the return value is 2, the virtual table
is not required to omit rows that are duplicates over the "colUsed"
columns, but if the virtual table can do that without
too much extra effort, it could potentially help the query to run faster.
This mode is used for queries
that have both DISTINCT and ORDER BY clauses.
</ol></p>
<p><p>The following table summarizes the conditions under which the
virtual table is allowed to set the "orderByConsumed" flag based on
the value returned by sqlite3_vtab_distinct(). This table is a
restatement of the previous four paragraphs:</p>
<p><table border=1 cellspacing=0 cellpadding=10 width="90%">
<tr>
<td valign="top">sqlite3_vtab_distinct() return value
<td valign="top">Rows are returned in aOrderBy order
<td valign="top">Rows with the same value in all aOrderBy columns are adjacent
<td valign="top">Duplicates over all colUsed columns may be omitted
<tr><td>0<td>yes<td>yes<td>no
<tr><td>1<td>no<td>yes<td>no
<tr><td>2<td>no<td>yes<td>yes
<tr><td>3<td>yes<td>yes<td>yes
</table></p>
<p>For the purposes of comparing virtual table output values to see if the
values are same value for sorting purposes, two NULL values are considered
to be the same. In other words, the comparison operator is "IS"
(or "IS NOT DISTINCT FROM") and not "==".</p>
<p>If a virtual table implementation is unable to meet the requirements
specified above, then it must not set the "orderByConsumed" flag in the
<a href="#sqlite3_index_info">sqlite3_index_info</a> object or an incorrect answer may result.</p>
<p>A virtual table implementation is always free to return rows in any order
it wants, as long as the "orderByConsumed" flag is not set. When the
the "orderByConsumed" flag is unset, the query planner will add extra
<a href="opcode.html">bytecode</a> to ensure that the final results returned by the SQL query are
ordered correctly. The use of the "orderByConsumed" flag and the
sqlite3_vtab_distinct() interface is merely an optimization. Careful
use of the sqlite3_vtab_distinct() interface and the "orderByConsumed"
flag might help queries against a virtual table to run faster. Being
overly aggressive and setting the "orderByConsumed" flag when it is not
valid to do so, on the other hand, might cause SQLite to return incorrect
results.
</p><hr><a name="sqlite3_vtab_in"></a>
<h2>Identify and handle IN constraints in xBestIndex</h2>
</div>
<blockquote><pre>
int sqlite3_vtab_in(sqlite3_index_info*, int iCons, int bHandle);
</pre></blockquote>
<p>
This interface may only be used from within an
<a href="vtab.html#xbestindex">xBestIndex() method</a> of a <a href="vtab.html">virtual table</a> implementation.
The result of invoking this interface from any other context is
undefined and probably harmful.</p>
<p>A constraint on a virtual table of the form
"<a href="lang_expr.html#in_op">column IN (...)</a>" is
communicated to the xBestIndex method as a
<a href="#SQLITE_INDEX_CONSTRAINT_EQ">SQLITE_INDEX_CONSTRAINT_EQ</a> constraint. If xBestIndex wants to use
this constraint, it must set the corresponding
aConstraintUsage[].argvIndex to a positive integer. Then, under
the usual mode of handling IN operators, SQLite generates <a href="opcode.html">bytecode</a>
that invokes the <a href="vtab.html#xfilter">xFilter() method</a> once for each value
on the right-hand side of the IN operator. Thus the virtual table
only sees a single value from the right-hand side of the IN operator
at a time.</p>
<p>In some cases, however, it would be advantageous for the virtual
table to see all values on the right-hand of the IN operator all at
once. The sqlite3_vtab_in() interfaces facilitates this in two ways:</p>
<p><ol>
<li><p>
A call to sqlite3_vtab_in(P,N,-1) will return true (non-zero)
if and only if the <a href="#sqlite3_index_info">P->aConstraint</a>[N] constraint
is an <a href="lang_expr.html#in_op">IN operator</a> that can be processed all at once. In other words,
sqlite3_vtab_in() with -1 in the third argument is a mechanism
by which the virtual table can ask SQLite if all-at-once processing
of the IN operator is even possible.</p>
<p><li><p>
A call to sqlite3_vtab_in(P,N,F) with F==1 or F==0 indicates
to SQLite that the virtual table does or does not want to process
the IN operator all-at-once, respectively. Thus when the third
parameter (F) is non-negative, this interface is the mechanism by
which the virtual table tells SQLite how it wants to process the
IN operator.
</ol></p>
<p>The sqlite3_vtab_in(P,N,F) interface can be invoked multiple times
within the same xBestIndex method call. For any given P,N pair,
the return value from sqlite3_vtab_in(P,N,F) will always be the same
within the same xBestIndex call. If the interface returns true
(non-zero), that means that the constraint is an IN operator
that can be processed all-at-once. If the constraint is not an IN
operator or cannot be processed all-at-once, then the interface returns
false.</p>
<p>All-at-once processing of the IN operator is selected if both of the
following conditions are met:</p>
<p><ol>
<li><p> The P->aConstraintUsage[N].argvIndex value is set to a positive
integer. This is how the virtual table tells SQLite that it wants to
use the N-th constraint.</p>
<p><li><p> The last call to sqlite3_vtab_in(P,N,F) for which F was
non-negative had F>=1.
</ol></p>
<p>If either or both of the conditions above are false, then SQLite uses
the traditional one-at-a-time processing strategy for the IN constraint.
If both conditions are true, then the argvIndex-th parameter to the
xFilter method will be an <a href="#sqlite3_value">sqlite3_value</a> that appears to be NULL,
but which can be passed to <a href="#sqlite3_vtab_in_first">sqlite3_vtab_in_first()</a> and
<a href="#sqlite3_vtab_in_first">sqlite3_vtab_in_next()</a> to find all values on the right-hand side
of the IN constraint.
</p><hr><a name="sqlite3_vtab_nochange"></a>
<h2>Determine If Virtual Table Column Access Is For UPDATE</h2>
</div>
<blockquote><pre>
int sqlite3_vtab_nochange(sqlite3_context*);
</pre></blockquote>
<p>
If the sqlite3_vtab_nochange(X) routine is called within the <a href="vtab.html#xcolumn">xColumn</a>
method of a <a href="vtab.html">virtual table</a>, then it might return true if the
column is being fetched as part of an UPDATE operation during which the
column value will not change. The virtual table implementation can use
this hint as permission to substitute a return value that is less
expensive to compute and that the corresponding
<a href="vtab.html#xupdate">xUpdate</a> method understands as a "no-change" value.</p>
<p>If the <a href="vtab.html#xcolumn">xColumn</a> method calls sqlite3_vtab_nochange() and finds that
the column is not changed by the UPDATE statement, then the xColumn
method can optionally return without setting a result, without calling
any of the <a href="#sqlite3_result_blob">sqlite3_result_xxxxx() interfaces</a>.
In that case, <a href="#sqlite3_value_blob">sqlite3_value_nochange(X)</a> will return true for the
same column in the <a href="vtab.html#xupdate">xUpdate</a> method.</p>
<p>The sqlite3_vtab_nochange() routine is an optimization. Virtual table
implementations should continue to give a correct answer even if the
sqlite3_vtab_nochange() interface were to always return false. In the
current implementation, the sqlite3_vtab_nochange() interface does always
returns false for the enhanced <a href="lang_update.html#upfrom">UPDATE FROM</a> statement.
</p><hr><a name="sqlite3_vtab_on_conflict"></a>
<h2>Determine The Virtual Table Conflict Policy</h2>
</div>
<blockquote><pre>
int sqlite3_vtab_on_conflict(sqlite3 *);
</pre></blockquote>
<p>
This function may only be called from within a call to the <a href="vtab.html#xupdate">xUpdate</a> method
of a <a href="vtab.html">virtual table</a> implementation for an INSERT or UPDATE operation. The
value returned is one of <a href="#SQLITE_FAIL">SQLITE_ROLLBACK</a>, <a href="#SQLITE_DENY">SQLITE_IGNORE</a>, <a href="#SQLITE_FAIL">SQLITE_FAIL</a>,
<a href="#SQLITE_ABORT">SQLITE_ABORT</a>, or <a href="#SQLITE_FAIL">SQLITE_REPLACE</a>, according to the <a href="lang_conflict.html">ON CONFLICT</a> mode
of the SQL statement that triggered the call to the <a href="vtab.html#xupdate">xUpdate</a> method of the
<a href="vtab.html">virtual table</a>.
</p><hr><a name="sqlite3_vtab_rhs_value"></a>
<h2>Constraint values in xBestIndex()</h2>
</div>
<blockquote><pre>
int sqlite3_vtab_rhs_value(sqlite3_index_info*, int, sqlite3_value **ppVal);
</pre></blockquote>
<p>
This API may only be used from within the <a href="vtab.html#xbestindex">xBestIndex method</a>
of a <a href="vtab.html">virtual table</a> implementation. The result of calling this interface
from outside of an xBestIndex method are undefined and probably harmful.</p>
<p>When the sqlite3_vtab_rhs_value(P,J,V) interface is invoked from within
the <a href="vtab.html#xbestindex">xBestIndex</a> method of a <a href="vtab.html">virtual table</a> implementation, with P being
a copy of the <a href="#sqlite3_index_info">sqlite3_index_info</a> object pointer passed into xBestIndex and
J being a 0-based index into P->aConstraint[], then this routine
attempts to set *V to the value of the right-hand operand of
that constraint if the right-hand operand is known. If the
right-hand operand is not known, then *V is set to a NULL pointer.
The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
and only if *V is set to a value. The sqlite3_vtab_rhs_value(P,J,V)
inteface returns SQLITE_NOTFOUND if the right-hand side of the J-th
constraint is not available. The sqlite3_vtab_rhs_value() interface
can return an result code other than SQLITE_OK or SQLITE_NOTFOUND if
something goes wrong.</p>
<p>The sqlite3_vtab_rhs_value() interface is usually only successful if
the right-hand operand of a constraint is a literal value in the original
SQL statement. If the right-hand operand is an expression or a reference
to some other column or a <a href="#sqlite3_bind_blob">host parameter</a>, then sqlite3_vtab_rhs_value()
will probably return <a href="#SQLITE_ABORT">SQLITE_NOTFOUND</a>.</p>
<p>Some constraints, such as <a href="#SQLITE_INDEX_CONSTRAINT_EQ">SQLITE_INDEX_CONSTRAINT_ISNULL</a> and
<a href="#SQLITE_INDEX_CONSTRAINT_EQ">SQLITE_INDEX_CONSTRAINT_ISNOTNULL</a>, have no right-hand operand. For such
constraints, sqlite3_vtab_rhs_value() always returns SQLITE_NOTFOUND.</p>
<p>The <a href="#sqlite3_value">sqlite3_value</a> object returned in *V is a protected sqlite3_value
and remains valid for the duration of the xBestIndex method call.
When xBestIndex returns, the sqlite3_value object returned by
sqlite3_vtab_rhs_value() is automatically deallocated.</p>
<p>The "_rhs_" in the name of this routine is an abbreviation for
"Right-Hand Side".
</p><hr><a name="sqlite3_wal_autocheckpoint"></a>
<h2>Configure an auto-checkpoint</h2>
</div>
<blockquote><pre>
int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
</pre></blockquote>
<p>
The <a href="#sqlite3_wal_autocheckpoint">sqlite3_wal_autocheckpoint(D,N)</a> is a wrapper around
<a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> that causes any database on <a href="#sqlite3">database connection</a> D
to automatically <a href="wal.html#ckpt">checkpoint</a>
after committing a transaction if there are N or
more frames in the <a href="wal.html">write-ahead log</a> file. Passing zero or
a negative value as the nFrame parameter disables automatic
checkpoints entirely.</p>
<p>The callback registered by this function replaces any existing callback
registered using <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a>. Likewise, registering a callback
using <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> disables the automatic checkpoint mechanism
configured by this function.</p>
<p>The <a href="pragma.html#pragma_wal_autocheckpoint">wal_autocheckpoint pragma</a> can be used to invoke this interface
from SQL.</p>
<p>Checkpoints initiated by this mechanism are
<a href="#sqlite3_wal_checkpoint_v2">PASSIVE</a>.</p>
<p>Every new <a href="#sqlite3">database connection</a> defaults to having the auto-checkpoint
enabled with a threshold of 1000 or <a href="compile.html#default_wal_autocheckpoint">SQLITE_DEFAULT_WAL_AUTOCHECKPOINT</a>
pages. The use of this interface
is only necessary if the default setting is found to be suboptimal
for a particular application.
</p><hr><a name="sqlite3_wal_checkpoint"></a>
<h2>Checkpoint a database</h2>
</div>
<blockquote><pre>
int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
</pre></blockquote>
<p>
The sqlite3_wal_checkpoint(D,X) is equivalent to
<a href="#sqlite3_wal_checkpoint_v2">sqlite3_wal_checkpoint_v2</a>(D,X,<a href="#SQLITE_CHECKPOINT_FULL">SQLITE_CHECKPOINT_PASSIVE</a>,0,0).</p>
<p>In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
<a href="wal.html">write-ahead log</a> for database X on <a href="#sqlite3">database connection</a> D to be
transferred into the database file and for the write-ahead log to
be reset. See the <a href="wal.html#ckpt">checkpointing</a> documentation for addition
information.</p>
<p>This interface used to be the only way to cause a checkpoint to
occur. But then the newer and more powerful <a href="#sqlite3_wal_checkpoint_v2">sqlite3_wal_checkpoint_v2()</a>
interface was added. This interface is retained for backwards
compatibility and as a convenience for applications that need to manually
start a callback but which do not need the full power (and corresponding
complication) of <a href="#sqlite3_wal_checkpoint_v2">sqlite3_wal_checkpoint_v2()</a>.
</p><hr><a name="sqlite3_wal_checkpoint_v2"></a>
<h2>Checkpoint a database</h2>
</div>
<blockquote><pre>
int sqlite3_wal_checkpoint_v2(
sqlite3 *db, /* Database handle */
const char *zDb, /* Name of attached database (or NULL) */
int eMode, /* SQLITE_CHECKPOINT_* value */
int *pnLog, /* OUT: Size of WAL log in frames */
int *pnCkpt /* OUT: Total number of frames checkpointed */
);
</pre></blockquote>
<p>
The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
operation on database X of <a href="#sqlite3">database connection</a> D in mode M. Status
information is written back into integers pointed to by L and C.
The M parameter must be a valid <a href="#SQLITE_CHECKPOINT_FULL">checkpoint mode</a>:</p>
<p><dl>
<dt>SQLITE_CHECKPOINT_PASSIVE<dd>
Checkpoint as many frames as possible without waiting for any database
readers or writers to finish, then sync the database file if all frames
in the log were checkpointed. The <a href="#sqlite3_busy_handler">busy-handler callback</a>
is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
On the other hand, passive mode might leave the checkpoint unfinished
if there are concurrent readers or writers.</p>
<p><dt>SQLITE_CHECKPOINT_FULL<dd>
This mode blocks (it invokes the
<a href="#sqlite3_busy_handler">busy-handler callback</a>) until there is no
database writer and all readers are reading from the most recent database
snapshot. It then checkpoints all frames in the log file and syncs the
database file. This mode blocks new database writers while it is pending,
but new database readers are allowed to continue unimpeded.</p>
<p><dt>SQLITE_CHECKPOINT_RESTART<dd>
This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
that after checkpointing the log file it blocks (calls the
<a href="#sqlite3_busy_handler">busy-handler callback</a>)
until all readers are reading from the database file only. This ensures
that the next writer will restart the log file from the beginning.
Like SQLITE_CHECKPOINT_FULL, this mode blocks new
database writer attempts while it is pending, but does not impede readers.</p>
<p><dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
addition that it also truncates the log file to zero bytes just prior
to a successful return.
</dl></p>
<p>If pnLog is not NULL, then *pnLog is set to the total number of frames in
the log file or to -1 if the checkpoint could not run because
of an error or because the database is not in <a href="wal.html">WAL mode</a>. If pnCkpt is not
NULL,then *pnCkpt is set to the total number of checkpointed frames in the
log file (including any that were already checkpointed before the function
was called) or to -1 if the checkpoint could not run due to an error or
because the database is not in WAL mode. Note that upon successful
completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.</p>
<p>All calls obtain an exclusive "checkpoint" lock on the database file. If
any other process is running a checkpoint operation at the same time, the
lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
busy-handler configured, it will not be invoked in this case.</p>
<p>The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
exclusive "writer" lock on the database file. If the writer lock cannot be
obtained immediately, and a busy-handler is configured, it is invoked and
the writer lock retried until either the busy-handler returns 0 or the lock
is successfully obtained. The busy-handler is also invoked while waiting for
database readers as described above. If the busy-handler returns 0 before
the writer lock is obtained or while waiting for database readers, the
checkpoint operation proceeds from that point in the same way as
SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
without blocking any further. SQLITE_BUSY is returned in this case.</p>
<p>If parameter zDb is NULL or points to a zero length string, then the
specified operation is attempted on all WAL databases <a href="lang_attach.html">attached</a> to
<a href="#sqlite3">database connection</a> db. In this case the
values written to output parameters *pnLog and *pnCkpt are undefined. If
an SQLITE_BUSY error is encountered when processing one or more of the
attached WAL databases, the operation is still attempted on any remaining
attached databases and SQLITE_BUSY is returned at the end. If any other
error occurs while processing an attached database, processing is abandoned
and the error code is returned to the caller immediately. If no error
(SQLITE_BUSY or otherwise) is encountered while processing the attached
databases, SQLITE_OK is returned.</p>
<p>If database zDb is the name of an attached database that is not in WAL
mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
zDb is not NULL (or a zero length string) and is not the name of any
attached database, SQLITE_ERROR is returned to the caller.</p>
<p>Unless it returns SQLITE_MISUSE,
the sqlite3_wal_checkpoint_v2() interface
sets the error information that is queried by
<a href="#sqlite3_errcode">sqlite3_errcode()</a> and <a href="#sqlite3_errcode">sqlite3_errmsg()</a>.</p>
<p>The <a href="pragma.html#pragma_wal_checkpoint">PRAGMA wal_checkpoint</a> command can be used to invoke this interface
from SQL.
</p><hr><a name="sqlite3_wal_hook"></a>
<h2>Write-Ahead Log Commit Hook</h2>
</div>
<blockquote><pre>
void *sqlite3_wal_hook(
sqlite3*,
int(*)(void *,sqlite3*,const char*,int),
void*
);
</pre></blockquote>
<p>
The <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> function is used to register a callback that
is invoked each time data is committed to a database in wal mode.</p>
<p>The callback is invoked by SQLite after the commit has taken place and
the associated write-lock on the database released, so the implementation
may read, write or <a href="wal.html#ckpt">checkpoint</a> the database as required.</p>
<p>The first parameter passed to the callback function when it is invoked
is a copy of the third parameter passed to sqlite3_wal_hook() when
registering the callback. The second is a copy of the database handle.
The third parameter is the name of the database that was written to -
either "main" or the name of an <a href="lang_attach.html">ATTACH</a>-ed database. The fourth parameter
is the number of pages currently in the write-ahead log file,
including those that were just committed.</p>
<p>The callback function should normally return <a href="#SQLITE_ABORT">SQLITE_OK</a>. If an error
code is returned, that error will propagate back up through the
SQLite code base to cause the statement that provoked the callback
to report an error, though the commit will have still occurred. If the
callback returns <a href="#SQLITE_ABORT">SQLITE_ROW</a> or <a href="#SQLITE_ABORT">SQLITE_DONE</a>, or if it returns a value
that does not correspond to any valid SQLite error code, the results
are undefined.</p>
<p>A single database handle may have at most a single write-ahead log callback
registered at one time. Calling <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> replaces any
previously registered write-ahead log callback. The return value is
a copy of the third parameter from the previous call, if any, or 0.
Note that the <a href="#sqlite3_wal_autocheckpoint">sqlite3_wal_autocheckpoint()</a> interface and the
<a href="pragma.html#pragma_wal_autocheckpoint">wal_autocheckpoint pragma</a> both invoke <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> and will
overwrite any prior <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> settings.
</p><hr><a name="SQLITE_ABORT"></a>
<h2>Result Codes</h2>
</div>
<blockquote><pre>
#define SQLITE_OK 0 /* Successful result */
/* beginning-of-error-codes */
#define SQLITE_ERROR 1 /* Generic error */
#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
#define SQLITE_PERM 3 /* Access permission denied */
#define SQLITE_ABORT 4 /* Callback routine requested an abort */
#define SQLITE_BUSY 5 /* The database file is locked */
#define SQLITE_LOCKED 6 /* A table in the database is locked */
#define SQLITE_NOMEM 7 /* A malloc() failed */
#define SQLITE_READONLY 8 /* Attempt to write a readonly database */
#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
#define SQLITE_CORRUPT 11 /* The database disk image is malformed */
#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
#define SQLITE_FULL 13 /* Insertion failed because database is full */
#define SQLITE_CANTOPEN 14 /* Unable to open the database file */
#define SQLITE_PROTOCOL 15 /* Database lock protocol error */
#define SQLITE_EMPTY 16 /* Internal use only */
#define SQLITE_SCHEMA 17 /* The database schema changed */
#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
#define SQLITE_MISMATCH 20 /* Data type mismatch */
#define SQLITE_MISUSE 21 /* Library used incorrectly */
#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
#define SQLITE_AUTH 23 /* Authorization denied */
#define SQLITE_FORMAT 24 /* Not used */
#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
#define SQLITE_NOTADB 26 /* File opened that is not a database file */
#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
/* end-of-error-codes */
</pre></blockquote>
<p>
Many SQLite functions return an integer result code from the set shown
here in order to indicate success or failure.</p>
<p>New error codes may be added in future versions of SQLite.</p>
<p>See also: <a href="#SQLITE_ABORT_ROLLBACK">extended result code definitions</a>
</p><hr><a name="SQLITE_ABORT_ROLLBACK"></a>
<h2>Extended Result Codes</h2>
</div>
<blockquote><pre>
#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8))
#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8))
#define SQLITE_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8))
#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8))
#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8))
#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8))
#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8))
#define SQLITE_IOERR_DATA (SQLITE_IOERR | (32<<8))
#define SQLITE_IOERR_CORRUPTFS (SQLITE_IOERR | (33<<8))
#define SQLITE_IOERR_IN_PAGE (SQLITE_IOERR | (34<<8))
#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8))
#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
#define SQLITE_BUSY_TIMEOUT (SQLITE_BUSY | (3<<8))
#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
#define SQLITE_CANTOPEN_SYMLINK (SQLITE_CANTOPEN | (6<<8))
#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8))
#define SQLITE_CORRUPT_INDEX (SQLITE_CORRUPT | (3<<8))
#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8))
#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8))
#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
#define SQLITE_CONSTRAINT_PINNED (SQLITE_CONSTRAINT |(11<<8))
#define SQLITE_CONSTRAINT_DATATYPE (SQLITE_CONSTRAINT |(12<<8))
#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
#define SQLITE_NOTICE_RBU (SQLITE_NOTICE | (3<<8))
#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8))
#define SQLITE_OK_SYMLINK (SQLITE_OK | (2<<8)) /* internal use only */
</pre></blockquote>
<p>
In its default configuration, SQLite API routines return one of 30 integer
<a href="rescode.html">result codes</a>. However, experience has shown that many of
these result codes are too coarse-grained. They do not provide as
much information about problems as programmers might like. In an effort to
address this, newer versions of SQLite (version 3.3.8 2006-10-09
and later) include
support for additional result codes that provide more detailed information
about errors. These <a href="rescode.html#extrc">extended result codes</a> are enabled or disabled
on a per database connection basis using the
<a href="#sqlite3_extended_result_codes">sqlite3_extended_result_codes()</a> API. Or, the extended code for
the most recent error can be obtained using
<a href="#sqlite3_errcode">sqlite3_extended_errcode()</a>.
</p><hr><a name="SQLITE_ACCESS_EXISTS"></a>
<h2>Flags for the xAccess VFS method</h2>
</div>
<blockquote><pre>
#define SQLITE_ACCESS_EXISTS 0
#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
#define SQLITE_ACCESS_READ 2 /* Unused */
</pre></blockquote>
<p>
These integer constants can be used as the third parameter to
the xAccess method of an <a href="#sqlite3_vfs">sqlite3_vfs</a> object. They determine
what kind of permissions the xAccess method is looking for.
With SQLITE_ACCESS_EXISTS, the xAccess method
simply checks whether the file exists.
With SQLITE_ACCESS_READWRITE, the xAccess method
checks whether the named directory is both readable and writable
(in other words, if files can be added, removed, and renamed within
the directory).
The SQLITE_ACCESS_READWRITE constant is currently used only by the
<a href="pragma.html#pragma_temp_store_directory">temp_store_directory pragma</a>, though this could change in a future
release of SQLite.
With SQLITE_ACCESS_READ, the xAccess method
checks whether the file is readable. The SQLITE_ACCESS_READ constant is
currently unused, though it might be used in a future release of
SQLite.
</p><hr><a name="SQLITE_ALTER_TABLE"></a>
<h2>Authorizer Action Codes</h2>
</div>
<blockquote><pre>
/******************************************* 3rd ************ 4th ***********/
#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
#define SQLITE_CREATE_VIEW 8 /* View Name NULL */
#define SQLITE_DELETE 9 /* Table Name NULL */
#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
#define SQLITE_DROP_TABLE 11 /* Table Name NULL */
#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
#define SQLITE_DROP_VIEW 17 /* View Name NULL */
#define SQLITE_INSERT 18 /* Table Name NULL */
#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
#define SQLITE_READ 20 /* Table Name Column Name */
#define SQLITE_SELECT 21 /* NULL NULL */
#define SQLITE_TRANSACTION 22 /* Operation NULL */
#define SQLITE_UPDATE 23 /* Table Name Column Name */
#define SQLITE_ATTACH 24 /* Filename NULL */
#define SQLITE_DETACH 25 /* Database Name NULL */
#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
#define SQLITE_REINDEX 27 /* Index Name NULL */
#define SQLITE_ANALYZE 28 /* Table Name NULL */
#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
#define SQLITE_FUNCTION 31 /* NULL Function Name */
#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
#define SQLITE_COPY 0 /* No longer used */
#define SQLITE_RECURSIVE 33 /* NULL NULL */
</pre></blockquote>
<p>
The <a href="#sqlite3_set_authorizer">sqlite3_set_authorizer()</a> interface registers a callback function
that is invoked to authorize certain SQL statement actions. The
second parameter to the callback is an integer code that specifies
what action is being authorized. These are the integer action codes that
the authorizer callback may be passed.</p>
<p>These action code values signify what kind of operation is to be
authorized. The 3rd and 4th parameters to the authorization
callback function will be parameters or NULL depending on which of these
codes is used as the second parameter. The 5th parameter to the
authorizer callback is the name of the database ("main", "temp",
etc.) if applicable. The 6th parameter to the authorizer callback
is the name of the inner-most trigger or view that is responsible for
the access attempt or NULL if this access attempt is directly from
top-level SQL code.
</p><hr><a name="SQLITE_ANY"></a>
<h2>Text Encodings</h2>
</div>
<blockquote><pre>
#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
#define SQLITE_UTF16 4 /* Use native byte order */
#define SQLITE_ANY 5 /* Deprecated */
#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
</pre></blockquote>
<p>
These constant define integer codes that represent the various
text encodings supported by SQLite.
</p><hr><a name="SQLITE_BLOB"></a>
<h2>Fundamental Datatypes</h2>
</div>
<blockquote><pre>
#define SQLITE_INTEGER 1
#define SQLITE_FLOAT 2
#define SQLITE_BLOB 4
#define SQLITE_NULL 5
#ifdef SQLITE_TEXT
# undef SQLITE_TEXT
#else
# define SQLITE_TEXT 3
#endif
#define SQLITE3_TEXT 3
</pre></blockquote>
<p>
Every value in SQLite has one of five fundamental datatypes:</p>
<p><ul>
<li> 64-bit signed integer
<li> 64-bit IEEE floating point number
<li> string
<li> BLOB
<li> NULL
</ul></p>
<p>These constants are codes for each of those types.</p>
<p>Note that the SQLITE_TEXT constant was also used in SQLite version 2
for a completely different meaning. Software that links against both
SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
SQLITE_TEXT.
</p><hr><a name="SQLITE_CHECKPOINT_FULL"></a>
<h2>Checkpoint Mode Values</h2>
</div>
<blockquote><pre>
#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */
#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */
#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for readers */
#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */
</pre></blockquote>
<p>
These constants define all valid values for the "checkpoint mode" passed
as the third parameter to the <a href="#sqlite3_wal_checkpoint_v2">sqlite3_wal_checkpoint_v2()</a> interface.
See the <a href="#sqlite3_wal_checkpoint_v2">sqlite3_wal_checkpoint_v2()</a> documentation for details on the
meaning of each of these checkpoint modes.
</p><hr><a name="SQLITE_CONFIG_COVERING_INDEX_SCAN"></a>
<h2>Configuration Options</h2>
</div>
<blockquote><pre>
#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
#define SQLITE_CONFIG_SERIALIZED 3 /* nil */
#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */
#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
#define SQLITE_CONFIG_PCACHE 14 /* no-op */
#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
#define SQLITE_CONFIG_URI 17 /* int */
#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */
#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */
#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */
#define SQLITE_CONFIG_ROWID_IN_VIEW 30 /* int* */
</pre></blockquote>
<p>
These constants are the available integer configuration options that
can be passed as the first argument to the <a href="#sqlite3_config">sqlite3_config()</a> interface.</p>
<p>Most of the configuration options for sqlite3_config()
will only work if invoked prior to <a href="#sqlite3_initialize">sqlite3_initialize()</a> or after
<a href="#sqlite3_initialize">sqlite3_shutdown()</a>. The few exceptions to this rule are called
"anytime configuration options".
Calling <a href="#sqlite3_config">sqlite3_config()</a> with a first argument that is not an
anytime configuration option in between calls to <a href="#sqlite3_initialize">sqlite3_initialize()</a> and
<a href="#sqlite3_initialize">sqlite3_shutdown()</a> is a no-op that returns SQLITE_MISUSE.</p>
<p>The set of anytime configuration options can change (by insertions
and/or deletions) from one release of SQLite to the next.
As of SQLite version 3.42.0, the complete set of anytime configuration
options is:
<ul>
<li> SQLITE_CONFIG_LOG
<li> SQLITE_CONFIG_PCACHE_HDRSZ
</ul></p>
<p>New configuration options may be added in future releases of SQLite.
Existing configuration options might be discontinued. Applications
should check the return code from <a href="#sqlite3_config">sqlite3_config()</a> to make sure that
the call worked. The <a href="#sqlite3_config">sqlite3_config()</a> interface will return a
non-zero <a href="rescode.html">error code</a> if a discontinued or unsupported configuration option
is invoked.</p>
<p><dl>
<a name="sqliteconfigsinglethread"></a>
<dt>SQLITE_CONFIG_SINGLETHREAD</dt>
<dd>There are no arguments to this option. This option sets the
<a href="threadsafe.html">threading mode</a> to Single-thread. In other words, it disables
all mutexing and puts SQLite into a mode where it can only be used
by a single thread. If SQLite is compiled with
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
it is not possible to change the <a href="threadsafe.html">threading mode</a> from its default
value of Single-thread and so <a href="#sqlite3_config">sqlite3_config()</a> will return
<a href="#SQLITE_ABORT">SQLITE_ERROR</a> if called with the SQLITE_CONFIG_SINGLETHREAD
configuration option.</dd></p>
<p><a name="sqliteconfigmultithread"></a>
<dt>SQLITE_CONFIG_MULTITHREAD</dt>
<dd>There are no arguments to this option. This option sets the
<a href="threadsafe.html">threading mode</a> to Multi-thread. In other words, it disables
mutexing on <a href="#sqlite3">database connection</a> and <a href="#sqlite3_stmt">prepared statement</a> objects.
The application is responsible for serializing access to
<a href="#sqlite3">database connections</a> and <a href="#sqlite3_stmt">prepared statements</a>. But other mutexes
are enabled so that SQLite will be safe to use in a multi-threaded
environment as long as no two threads attempt to use the same
<a href="#sqlite3">database connection</a> at the same time. If SQLite is compiled with
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
it is not possible to set the Multi-thread <a href="threadsafe.html">threading mode</a> and
<a href="#sqlite3_config">sqlite3_config()</a> will return <a href="#SQLITE_ABORT">SQLITE_ERROR</a> if called with the
SQLITE_CONFIG_MULTITHREAD configuration option.</dd></p>
<p><a name="sqliteconfigserialized"></a>
<dt>SQLITE_CONFIG_SERIALIZED</dt>
<dd>There are no arguments to this option. This option sets the
<a href="threadsafe.html">threading mode</a> to Serialized. In other words, this option enables
all mutexes including the recursive
mutexes on <a href="#sqlite3">database connection</a> and <a href="#sqlite3_stmt">prepared statement</a> objects.
In this mode (which is the default when SQLite is compiled with
<a href="compile.html#threadsafe">SQLITE_THREADSAFE=1</a>) the SQLite library will itself serialize access
to <a href="#sqlite3">database connections</a> and <a href="#sqlite3_stmt">prepared statements</a> so that the
application is free to use the same <a href="#sqlite3">database connection</a> or the
same <a href="#sqlite3_stmt">prepared statement</a> in different threads at the same time.
If SQLite is compiled with
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
it is not possible to set the Serialized <a href="threadsafe.html">threading mode</a> and
<a href="#sqlite3_config">sqlite3_config()</a> will return <a href="#SQLITE_ABORT">SQLITE_ERROR</a> if called with the
SQLITE_CONFIG_SERIALIZED configuration option.</dd></p>
<p><a name="sqliteconfigmalloc"></a>
<dt>SQLITE_CONFIG_MALLOC</dt>
<dd> The SQLITE_CONFIG_MALLOC option takes a single argument which is
a pointer to an instance of the <a href="#sqlite3_mem_methods">sqlite3_mem_methods</a> structure.
The argument specifies
alternative low-level memory allocation routines to be used in place of
the memory allocation routines built into SQLite. SQLite makes
its own private copy of the content of the <a href="#sqlite3_mem_methods">sqlite3_mem_methods</a> structure
before the <a href="#sqlite3_config">sqlite3_config()</a> call returns.</dd></p>
<p><a name="sqliteconfiggetmalloc"></a>
<dt>SQLITE_CONFIG_GETMALLOC</dt>
<dd> The SQLITE_CONFIG_GETMALLOC option takes a single argument which
is a pointer to an instance of the <a href="#sqlite3_mem_methods">sqlite3_mem_methods</a> structure.
The <a href="#sqlite3_mem_methods">sqlite3_mem_methods</a>
structure is filled with the currently defined memory allocation routines.
This option can be used to overload the default memory allocation
routines with a wrapper that simulations memory allocation failure or
tracks memory usage, for example. </dd></p>
<p><a name="sqliteconfigsmallmalloc"></a>
<dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
<dd> The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
type int, interpreted as a boolean, which if true provides a hint to
SQLite that it should avoid large memory allocations if possible.
SQLite will run faster if it is free to make large memory allocations,
but some application might prefer to run slower in exchange for
guarantees about memory fragmentation that are possible if large
allocations are avoided. This hint is normally off.
</dd></p>
<p><a name="sqliteconfigmemstatus"></a>
<dt>SQLITE_CONFIG_MEMSTATUS</dt>
<dd> The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
interpreted as a boolean, which enables or disables the collection of
memory allocation statistics. When memory allocation statistics are
disabled, the following SQLite interfaces become non-operational:
<ul>
<li> <a href="#sqlite3_hard_heap_limit64">sqlite3_hard_heap_limit64()</a>
<li> <a href="#sqlite3_memory_highwater">sqlite3_memory_used()</a>
<li> <a href="#sqlite3_memory_highwater">sqlite3_memory_highwater()</a>
<li> <a href="#sqlite3_hard_heap_limit64">sqlite3_soft_heap_limit64()</a>
<li> <a href="#sqlite3_status">sqlite3_status64()</a>
</ul>
Memory allocation statistics are enabled by default unless SQLite is
compiled with <a href="compile.html#default_memstatus">SQLITE_DEFAULT_MEMSTATUS</a>=0 in which case memory
allocation statistics are disabled by default.
</dd></p>
<p><a name="sqliteconfigscratch"></a>
<dt>SQLITE_CONFIG_SCRATCH</dt>
<dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
</dd></p>
<p><a name="sqliteconfigpagecache"></a>
<dt>SQLITE_CONFIG_PAGECACHE</dt>
<dd> The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
that SQLite can use for the database page cache with the default page
cache implementation.
This configuration option is a no-op if an application-defined page
cache implementation is loaded using the <a href="#sqliteconfigpcache2">SQLITE_CONFIG_PCACHE2</a>.
There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
8-byte aligned memory (pMem), the size of each page cache line (sz),
and the number of cache lines (N).
The sz argument should be the size of the largest database page
(a power of two between 512 and 65536) plus some extra bytes for each
page header. The number of extra bytes needed by the page header
can be determined using <a href="#sqliteconfigpcachehdrsz">SQLITE_CONFIG_PCACHE_HDRSZ</a>.
It is harmless, apart from the wasted memory,
for the sz parameter to be larger than necessary. The pMem
argument must be either a NULL pointer or a pointer to an 8-byte
aligned block of memory of at least sz*N bytes, otherwise
subsequent behavior is undefined.
When pMem is not NULL, SQLite will strive to use the memory provided
to satisfy page cache needs, falling back to <a href="#sqlite3_free">sqlite3_malloc()</a> if
a page cache line is larger than sz bytes or if all of the pMem buffer
is exhausted.
If pMem is NULL and N is non-zero, then each database connection
does an initial bulk allocation for page cache memory
from <a href="#sqlite3_free">sqlite3_malloc()</a> sufficient for N cache lines if N is positive or
of -1024*N bytes if N is negative, . If additional
page cache memory is needed beyond what is provided by the initial
allocation, then SQLite goes to <a href="#sqlite3_free">sqlite3_malloc()</a> separately for each
additional cache line. </dd></p>
<p><a name="sqliteconfigheap"></a>
<dt>SQLITE_CONFIG_HEAP</dt>
<dd> The SQLITE_CONFIG_HEAP option specifies a static memory buffer
that SQLite will use for all of its dynamic memory allocation needs
beyond those provided for by <a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>.
The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
with either <a href="compile.html#enable_memsys3">SQLITE_ENABLE_MEMSYS3</a> or <a href="compile.html#enable_memsys5">SQLITE_ENABLE_MEMSYS5</a> and returns
<a href="#SQLITE_ABORT">SQLITE_ERROR</a> if invoked otherwise.
There are three arguments to SQLITE_CONFIG_HEAP:
An 8-byte aligned pointer to the memory,
the number of bytes in the memory buffer, and the minimum allocation size.
If the first pointer (the memory pointer) is NULL, then SQLite reverts
to using its default memory allocator (the system malloc() implementation),
undoing any prior invocation of <a href="#sqliteconfigmalloc">SQLITE_CONFIG_MALLOC</a>. If the
memory pointer is not NULL then the alternative memory
allocator is engaged to handle all of SQLites memory allocation needs.
The first pointer (the memory pointer) must be aligned to an 8-byte
boundary or subsequent behavior of SQLite will be undefined.
The minimum allocation size is capped at 2**12. Reasonable values
for the minimum allocation size are 2**5 through 2**8.</dd></p>
<p><a name="sqliteconfigmutex"></a>
<dt>SQLITE_CONFIG_MUTEX</dt>
<dd> The SQLITE_CONFIG_MUTEX option takes a single argument which is a
pointer to an instance of the <a href="#sqlite3_mutex_methods">sqlite3_mutex_methods</a> structure.
The argument specifies alternative low-level mutex routines to be used
in place the mutex routines built into SQLite. SQLite makes a copy of
the content of the <a href="#sqlite3_mutex_methods">sqlite3_mutex_methods</a> structure before the call to
<a href="#sqlite3_config">sqlite3_config()</a> returns. If SQLite is compiled with
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
the entire mutexing subsystem is omitted from the build and hence calls to
<a href="#sqlite3_config">sqlite3_config()</a> with the SQLITE_CONFIG_MUTEX configuration option will
return <a href="#SQLITE_ABORT">SQLITE_ERROR</a>.</dd></p>
<p><a name="sqliteconfiggetmutex"></a>
<dt>SQLITE_CONFIG_GETMUTEX</dt>
<dd> The SQLITE_CONFIG_GETMUTEX option takes a single argument which
is a pointer to an instance of the <a href="#sqlite3_mutex_methods">sqlite3_mutex_methods</a> structure. The
<a href="#sqlite3_mutex_methods">sqlite3_mutex_methods</a>
structure is filled with the currently defined mutex routines.
This option can be used to overload the default mutex allocation
routines with a wrapper used to track mutex usage for performance
profiling or testing, for example. If SQLite is compiled with
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
the entire mutexing subsystem is omitted from the build and hence calls to
<a href="#sqlite3_config">sqlite3_config()</a> with the SQLITE_CONFIG_GETMUTEX configuration option will
return <a href="#SQLITE_ABORT">SQLITE_ERROR</a>.</dd></p>
<p><a name="sqliteconfiglookaside"></a>
<dt>SQLITE_CONFIG_LOOKASIDE</dt>
<dd> The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
the default size of lookaside memory on each <a href="#sqlite3">database connection</a>.
The first argument is the
size of each lookaside buffer slot and the second is the number of
slots allocated to each database connection. SQLITE_CONFIG_LOOKASIDE
sets the <i>default</i> lookaside size. The <a href="#sqlitedbconfiglookaside">SQLITE_DBCONFIG_LOOKASIDE</a>
option to <a href="#sqlite3_db_config">sqlite3_db_config()</a> can be used to change the lookaside
configuration on individual connections. </dd></p>
<p><a name="sqliteconfigpcache2"></a>
<dt>SQLITE_CONFIG_PCACHE2</dt>
<dd> The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
a pointer to an <a href="#sqlite3_pcache_methods2">sqlite3_pcache_methods2</a> object. This object specifies
the interface to a custom page cache implementation.
SQLite makes a copy of the <a href="#sqlite3_pcache_methods2">sqlite3_pcache_methods2</a> object.</dd></p>
<p><a name="sqliteconfiggetpcache2"></a>
<dt>SQLITE_CONFIG_GETPCACHE2</dt>
<dd> The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
is a pointer to an <a href="#sqlite3_pcache_methods2">sqlite3_pcache_methods2</a> object. SQLite copies of
the current page cache implementation into that object. </dd></p>
<p><a name="sqliteconfiglog"></a>
<dt>SQLITE_CONFIG_LOG</dt>
<dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
global <a href="errlog.html">error log</a>.
(The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
function with a call signature of void(*)(void*,int,const char*),
and a pointer to void. If the function pointer is not NULL, it is
invoked by <a href="#sqlite3_log">sqlite3_log()</a> to process each logging event. If the
function pointer is NULL, the <a href="#sqlite3_log">sqlite3_log()</a> interface becomes a no-op.
The void pointer that is the second argument to SQLITE_CONFIG_LOG is
passed through as the first parameter to the application-defined logger
function whenever that function is invoked. The second parameter to
the logger function is a copy of the first parameter to the corresponding
<a href="#sqlite3_log">sqlite3_log()</a> call and is intended to be a <a href="rescode.html">result code</a> or an
<a href="rescode.html#extrc">extended result code</a>. The third parameter passed to the logger is
log message after formatting via <a href="#sqlite3_mprintf">sqlite3_snprintf()</a>.
The SQLite logging interface is not reentrant; the logger function
supplied by the application must not invoke any SQLite interface.
In a multi-threaded application, the application-defined logger
function must be threadsafe. </dd></p>
<p><a name="sqliteconfiguri"></a>
<dt>SQLITE_CONFIG_URI
<dd>The SQLITE_CONFIG_URI option takes a single argument of type int.
If non-zero, then URI handling is globally enabled. If the parameter is zero,
then URI handling is globally disabled. If URI handling is globally
enabled, all filenames passed to <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open_v2()</a>,
<a href="#sqlite3_open">sqlite3_open16()</a> or
specified as part of <a href="lang_attach.html">ATTACH</a> commands are interpreted as URIs, regardless
of whether or not the <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_URI</a> flag is set when the database
connection is opened. If it is globally disabled, filenames are
only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
database connection is opened. By default, URI handling is globally
disabled. The default value may be changed by compiling with the
<a href="compile.html#use_uri">SQLITE_USE_URI</a> symbol defined.</p>
<p><a name="sqliteconfigcoveringindexscan"></a>
<dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
<dd>The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
argument which is interpreted as a boolean in order to enable or disable
the use of covering indices for full table scans in the query optimizer.
The default setting is determined
by the <a href="compile.html#allow_covering_index_scan">SQLITE_ALLOW_COVERING_INDEX_SCAN</a> compile-time option, or is "on"
if that compile-time option is omitted.
The ability to disable the use of covering indices for full table scans
is because some incorrectly coded legacy applications might malfunction
when the optimization is enabled. Providing the ability to
disable the optimization allows the older, buggy application code to work
without change even with newer versions of SQLite.</p>
<p><a name="sqliteconfigpcache"></a>
<a name="sqliteconfiggetpcache"></a>
<dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
<dd> These options are obsolete and should not be used by new code.
They are retained for backwards compatibility but are now no-ops.
</dd></p>
<p><a name="sqliteconfigsqllog"></a>
<dt>SQLITE_CONFIG_SQLLOG
<dd>This option is only available if sqlite is compiled with the
<a href="compile.html#enable_sqllog">SQLITE_ENABLE_SQLLOG</a> pre-processor macro defined. The first argument should
be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
The second should be of type (void*). The callback is invoked by the library
in three separate circumstances, identified by the value passed as the
fourth parameter. If the fourth parameter is 0, then the database connection
passed as the second argument has just been opened. The third argument
points to a buffer containing the name of the main database file. If the
fourth parameter is 1, then the SQL statement that the third parameter
points to has just been executed. Or, if the fourth parameter is 2, then
the connection being passed as the second parameter is being closed. The
third parameter is passed NULL In this case. An example of using this
configuration option can be seen in the "test_sqllog.c" source file in
the canonical SQLite source tree.</dd></p>
<p><a name="sqliteconfigmmapsize"></a>
<dt>SQLITE_CONFIG_MMAP_SIZE
<dd>SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
that are the default mmap size limit (the default setting for
<a href="pragma.html#pragma_mmap_size">PRAGMA mmap_size</a>) and the maximum allowed mmap size limit.
The default setting can be overridden by each database connection using
either the <a href="pragma.html#pragma_mmap_size">PRAGMA mmap_size</a> command, or by using the
<a href="#sqlitefcntlmmapsize">SQLITE_FCNTL_MMAP_SIZE</a> file control. The maximum allowed mmap size
will be silently truncated if necessary so that it does not exceed the
compile-time maximum mmap size set by the
<a href="compile.html#max_mmap_size">SQLITE_MAX_MMAP_SIZE</a> compile-time option.
If either argument to this option is negative, then that argument is
changed to its compile-time default.</p>
<p><a name="sqliteconfigwin32heapsize"></a>
<dt>SQLITE_CONFIG_WIN32_HEAPSIZE
<dd>The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
compiled for Windows with the <a href="compile.html#win32_malloc">SQLITE_WIN32_MALLOC</a> pre-processor macro
defined. SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
that specifies the maximum size of the created heap.</p>
<p><a name="sqliteconfigpcachehdrsz"></a>
<dt>SQLITE_CONFIG_PCACHE_HDRSZ
<dd>The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
is a pointer to an integer and writes into that integer the number of extra
bytes per page required for each page in <a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>.
The amount of extra space required can change depending on the compiler,
target platform, and SQLite version.</p>
<p><a name="sqliteconfigpmasz"></a>
<dt>SQLITE_CONFIG_PMASZ
<dd>The SQLITE_CONFIG_PMASZ option takes a single parameter which
is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
sorter to that integer. The default minimum PMA Size is set by the
<a href="compile.html#sorter_pmasz">SQLITE_SORTER_PMASZ</a> compile-time option. New threads are launched
to help with sort operations when multithreaded sorting
is enabled (using the <a href="pragma.html#pragma_threads">PRAGMA threads</a> command) and the amount of content
to be sorted exceeds the page size times the minimum of the
<a href="pragma.html#pragma_cache_size">PRAGMA cache_size</a> setting and this value.</p>
<p><a name="sqliteconfigstmtjrnlspill"></a>
<dt>SQLITE_CONFIG_STMTJRNL_SPILL
<dd>The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
becomes the <a href="tempfiles.html#stmtjrnl">statement journal</a> spill-to-disk threshold.
<a href="tempfiles.html#stmtjrnl">Statement journals</a> are held in memory until their size (in bytes)
exceeds this threshold, at which point they are written to disk.
Or if the threshold is -1, statement journals are always held
exclusively in memory.
Since many statement journals never become large, setting the spill
threshold to a value such as 64KiB can greatly reduce the amount of
I/O required to support statement rollback.
The default value for this setting is controlled by the
<a href="compile.html#stmtjrnl_spill">SQLITE_STMTJRNL_SPILL</a> compile-time option.</p>
<p><a name="sqliteconfigsorterrefsize"></a>
<dt>SQLITE_CONFIG_SORTERREF_SIZE
<dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
of type (int) - the new value of the sorter-reference size threshold.
Usually, when SQLite uses an external sort to order records according
to an ORDER BY clause, all fields required by the caller are present in the
sorted records. However, if SQLite determines based on the declared type
of a table column that its values are likely to be very large - larger
than the configured sorter-reference size threshold - then a reference
is stored in each sorted record and the required column values loaded
from the database as records are returned in sorted order. The default
value for this option is to never use this optimization. Specifying a
negative value for this option restores the default behavior.
This option is only available if SQLite is compiled with the
<a href="compile.html#enable_sorter_references">SQLITE_ENABLE_SORTER_REFERENCES</a> compile-time option.</p>
<p><a name="sqliteconfigmemdbmaxsize"></a>
<dt>SQLITE_CONFIG_MEMDB_MAXSIZE
<dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
<a href="#sqlite3_int64">sqlite3_int64</a> parameter which is the default maximum size for an in-memory
database created using <a href="#sqlite3_deserialize">sqlite3_deserialize()</a>. This default maximum
size can be adjusted up or down for individual databases using the
<a href="#sqlitefcntlsizelimit">SQLITE_FCNTL_SIZE_LIMIT</a> <a href="#sqlite3_file_control">file-control</a>. If this
configuration setting is never used, then the default maximum is determined
by the <a href="compile.html#memdb_default_maxsize">SQLITE_MEMDB_DEFAULT_MAXSIZE</a> compile-time option. If that
compile-time option is not set, then the default maximum is 1073741824.</p>
<p><a name="sqliteconfigrowidinview"></a>
<dt>SQLITE_CONFIG_ROWID_IN_VIEW
<dd>The SQLITE_CONFIG_ROWID_IN_VIEW option enables or disables the ability
for VIEWs to have a ROWID. The capability can only be enabled if SQLite is
compiled with -DSQLITE_ALLOW_ROWID_IN_VIEW, in which case the capability
defaults to on. This configuration option queries the current setting or
changes the setting to off or on. The argument is a pointer to an integer.
If that integer initially holds a value of 1, then the ability for VIEWs to
have ROWIDs is activated. If the integer initially holds zero, then the
ability is deactivated. Any other initial value for the integer leaves the
setting unchanged. After changes, if any, the integer is written with
a 1 or 0, if the ability for VIEWs to have ROWIDs is on or off. If SQLite
is compiled without -DSQLITE_ALLOW_ROWID_IN_VIEW (which is the usual and
recommended case) then the integer is always filled with zero, regardless
if its initial value.
</dl>
</p><hr><a name="SQLITE_DBCONFIG_DEFENSIVE"></a>
<h2>Database Connection Configuration Options</h2>
</div>
<blockquote><pre>
#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */
#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */
#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */
#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */
#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */
#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */
#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */
#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */
#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */
#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */
#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */
#define SQLITE_DBCONFIG_STMT_SCANSTATUS 1018 /* int int* */
#define SQLITE_DBCONFIG_REVERSE_SCANORDER 1019 /* int int* */
#define SQLITE_DBCONFIG_MAX 1019 /* Largest DBCONFIG */
</pre></blockquote>
<p>
These constants are the available integer configuration options that
can be passed as the second argument to the <a href="#sqlite3_db_config">sqlite3_db_config()</a> interface.</p>
<p>New configuration options may be added in future releases of SQLite.
Existing configuration options might be discontinued. Applications
should check the return code from <a href="#sqlite3_db_config">sqlite3_db_config()</a> to make sure that
the call worked. The <a href="#sqlite3_db_config">sqlite3_db_config()</a> interface will return a
non-zero <a href="rescode.html">error code</a> if a discontinued or unsupported configuration option
is invoked.</p>
<p><dl>
<a name="sqlitedbconfiglookaside"></a>
<dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
<dd> This option takes three additional arguments that determine the
<a href="malloc.html#lookaside">lookaside memory allocator</a> configuration for the <a href="#sqlite3">database connection</a>.
The first argument (the third parameter to <a href="#sqlite3_db_config">sqlite3_db_config()</a> is a
pointer to a memory buffer to use for lookaside memory.
The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
may be NULL in which case SQLite will allocate the
lookaside buffer itself using <a href="#sqlite3_free">sqlite3_malloc()</a>. The second argument is the
size of each lookaside buffer slot. The third argument is the number of
slots. The size of the buffer in the first argument must be greater than
or equal to the product of the second and third arguments. The buffer
must be aligned to an 8-byte boundary. If the second argument to
SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
rounded down to the next smaller multiple of 8. The lookaside memory
configuration for a database connection can only be changed when that
connection is not currently using lookaside memory, or in other words
when the "current value" returned by
<a href="#sqlite3_db_status">sqlite3_db_status</a>(D,<a href="#sqlitedbstatuslookasideused">SQLITE_DBSTATUS_LOOKASIDE_USED</a>,...) is zero.
Any attempt to change the lookaside memory configuration when lookaside
memory is in use leaves the configuration unchanged and returns
<a href="#SQLITE_ABORT">SQLITE_BUSY</a>.</dd></p>
<p><a name="sqlitedbconfigenablefkey"></a>
<dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
<dd> This option is used to enable or disable the enforcement of
<a href="foreignkeys.html">foreign key constraints</a>. There should be two additional arguments.
The first argument is an integer which is 0 to disable FK enforcement,
positive to enable FK enforcement or negative to leave FK enforcement
unchanged. The second parameter is a pointer to an integer into which
is written 0 or 1 to indicate whether FK enforcement is off or on
following this call. The second parameter may be a NULL pointer, in
which case the FK enforcement setting is not reported back. </dd></p>
<p><a name="sqlitedbconfigenabletrigger"></a>
<dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
<dd> This option is used to enable or disable <a href="lang_createtrigger.html">triggers</a>.
There should be two additional arguments.
The first argument is an integer which is 0 to disable triggers,
positive to enable triggers or negative to leave the setting unchanged.
The second parameter is a pointer to an integer into which
is written 0 or 1 to indicate whether triggers are disabled or enabled
following this call. The second parameter may be a NULL pointer, in
which case the trigger setting is not reported back.</p>
<p><p>Originally this option disabled all triggers. However, since
SQLite version 3.35.0, TEMP triggers are still allowed even if
this option is off. So, in other words, this option now only disables
triggers in the main database schema or in the schemas of ATTACH-ed
databases. </dd></p>
<p><a name="sqlitedbconfigenableview"></a>
<dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
<dd> This option is used to enable or disable <a href="lang_createview.html">views</a>.
There should be two additional arguments.
The first argument is an integer which is 0 to disable views,
positive to enable views or negative to leave the setting unchanged.
The second parameter is a pointer to an integer into which
is written 0 or 1 to indicate whether views are disabled or enabled
following this call. The second parameter may be a NULL pointer, in
which case the view setting is not reported back.</p>
<p><p>Originally this option disabled all views. However, since
SQLite version 3.35.0, TEMP views are still allowed even if
this option is off. So, in other words, this option now only disables
views in the main database schema or in the schemas of ATTACH-ed
databases. </dd></p>
<p><a name="sqlitedbconfigenablefts3tokenizer"></a>
<dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
<dd> This option is used to enable or disable the
<a href="fts3.html#f3tknzr">fts3_tokenizer()</a> function which is part of the
<a href="fts3.html">FTS3</a> full-text search engine extension.
There should be two additional arguments.
The first argument is an integer which is 0 to disable fts3_tokenizer() or
positive to enable fts3_tokenizer() or negative to leave the setting
unchanged.
The second parameter is a pointer to an integer into which
is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
following this call. The second parameter may be a NULL pointer, in
which case the new setting is not reported back. </dd></p>
<p><a name="sqlitedbconfigenableloadextension"></a>
<dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
<dd> This option is used to enable or disable the <a href="#sqlite3_load_extension">sqlite3_load_extension()</a>
interface independently of the <a href="lang_corefunc.html#load_extension">load_extension()</a> SQL function.
The <a href="#sqlite3_enable_load_extension">sqlite3_enable_load_extension()</a> API enables or disables both the
C-API <a href="#sqlite3_load_extension">sqlite3_load_extension()</a> and the SQL function <a href="lang_corefunc.html#load_extension">load_extension()</a>.
There should be two additional arguments.
When the first argument to this interface is 1, then only the C-API is
enabled and the SQL function remains disabled. If the first argument to
this interface is 0, then both the C-API and the SQL function are disabled.
If the first argument is -1, then no changes are made to state of either the
C-API or the SQL function.
The second parameter is a pointer to an integer into which
is written 0 or 1 to indicate whether <a href="#sqlite3_load_extension">sqlite3_load_extension()</a> interface
is disabled or enabled following this call. The second parameter may
be a NULL pointer, in which case the new setting is not reported back.
</dd></p>
<p><a name="sqlitedbconfigmaindbname"></a>
<dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
<dd> This option is used to change the name of the "main" database
schema. The sole argument is a pointer to a constant UTF8 string
which will become the new schema name in place of "main". SQLite
does not make a copy of the new main schema name string, so the application
must ensure that the argument passed into this DBCONFIG option is unchanged
until after the database connection closes.
</dd></p>
<p><a name="sqlitedbconfignockptonclose"></a>
<dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
<dd> Usually, when a database in wal mode is closed or detached from a
database handle, SQLite checks if this will mean that there are now no
connections at all to the database. If so, it performs a checkpoint
operation before closing the connection. This option may be used to
override this behavior. The first parameter passed to this operation
is an integer - positive to disable checkpoints-on-close, or zero (the
default) to enable them, and negative to leave the setting unchanged.
The second parameter is a pointer to an integer
into which is written 0 or 1 to indicate whether checkpoints-on-close
have been disabled - 0 if they are not disabled, 1 if they are.
</dd></p>
<p><a name="sqlitedbconfigenableqpsg"></a>
<dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
<dd>The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
the <a href="queryplanner-ng.html#qpstab">query planner stability guarantee</a> (QPSG). When the QPSG is active,
a single SQL query statement will always use the same algorithm regardless
of values of <a href="lang_expr.html#varparam">bound parameters</a>. The QPSG disables some query optimizations
that look at the values of bound parameters, which can make some queries
slower. But the QPSG has the advantage of more predictable behavior. With
the QPSG active, SQLite will always use the same query plan in the field as
was used during testing in the lab.
The first argument to this setting is an integer which is 0 to disable
the QPSG, positive to enable QPSG, or negative to leave the setting
unchanged. The second parameter is a pointer to an integer into which
is written 0 or 1 to indicate whether the QPSG is disabled or enabled
following this call.
</dd></p>
<p><a name="sqlitedbconfigtriggereqp"></a>
<dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
<dd> By default, the output of EXPLAIN QUERY PLAN commands does not
include output for any operations performed by trigger programs. This
option is used to set or clear (the default) a flag that governs this
behavior. The first parameter passed to this operation is an integer -
positive to enable output for trigger programs, or zero to disable it,
or negative to leave the setting unchanged.
The second parameter is a pointer to an integer into which is written
0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
it is not disabled, 1 if it is.
</dd></p>
<p><a name="sqlitedbconfigresetdatabase"></a>
<dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
<dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
<a href="lang_vacuum.html">VACUUM</a> in order to reset a database back to an empty database
with no schema and no content. The following process works even for
a badly corrupted database file:
<ol>
<li> If the database connection is newly opened, make sure it has read the
database schema by preparing then discarding some query against the
database, or calling sqlite3_table_column_metadata(), ignoring any
errors. This step is only necessary if the application desires to keep
the database in WAL mode after the reset if it was in WAL mode before
the reset.
<li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
<li> <a href="#sqlite3_exec">sqlite3_exec</a>(db, "<a href="lang_vacuum.html">VACUUM</a>", 0, 0, 0);
<li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
</ol>
Because resetting a database is destructive and irreversible, the
process requires the use of this obscure API and multiple steps to
help ensure that it does not happen by accident. Because this
feature must be capable of resetting corrupt databases, and
shutting down virtual tables may require access to that corrupt
storage, the library must abandon any installed virtual tables
without calling their xDestroy() methods.</p>
<p><a name="sqlitedbconfigdefensive"></a>
<dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
<dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
"defensive" flag for a database connection. When the defensive
flag is enabled, language features that allow ordinary SQL to
deliberately corrupt the database file are disabled. The disabled
features include but are not limited to the following:
<ul>
<li> The <a href="pragma.html#pragma_writable_schema">PRAGMA writable_schema=ON</a> statement.
<li> The <a href="pragma.html#pragma_journal_mode">PRAGMA journal_mode=OFF</a> statement.
<li> The <a href="pragma.html#pragma_schema_version">PRAGMA schema_version=N</a> statement.
<li> Writes to the <a href="dbpage.html">sqlite_dbpage</a> virtual table.
<li> Direct writes to <a href="vtab.html#xshadowname">shadow tables</a>.
</ul>
</dd></p>
<p><a name="sqlitedbconfigwritableschema"></a>
<dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
<dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
"writable_schema" flag. This has the same effect and is logically equivalent
to setting <a href="pragma.html#pragma_writable_schema">PRAGMA writable_schema=ON</a> or <a href="pragma.html#pragma_writable_schema">PRAGMA writable_schema=OFF</a>.
The first argument to this setting is an integer which is 0 to disable
the writable_schema, positive to enable writable_schema, or negative to
leave the setting unchanged. The second parameter is a pointer to an
integer into which is written 0 or 1 to indicate whether the writable_schema
is enabled or disabled following this call.
</dd></p>
<p><a name="sqlitedbconfiglegacyaltertable"></a>
<dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
<dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
the legacy behavior of the <a href="lang_altertable.html#altertabrename">ALTER TABLE RENAME</a> command such it
behaves as it did prior to <a href="releaselog/3_24_0.html">version 3.24.0</a> (2018-06-04). See the
"Compatibility Notice" on the <a href="lang_altertable.html#altertabrename">ALTER TABLE RENAME documentation</a> for
additional information. This feature can also be turned on and off
using the <a href="pragma.html#pragma_legacy_alter_table">PRAGMA legacy_alter_table</a> statement.
</dd></p>
<p><a name="sqlitedbconfigdqsdml"></a>
<dt>SQLITE_DBCONFIG_DQS_DML</dt>
<dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
the legacy <a href="quirks.html#dblquote">double-quoted string literal</a> misfeature for DML statements
only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
default value of this setting is determined by the <a href="compile.html#dqs">-DSQLITE_DQS</a>
compile-time option.
</dd></p>
<p><a name="sqlitedbconfigdqsddl"></a>
<dt>SQLITE_DBCONFIG_DQS_DDL</dt>
<dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
the legacy <a href="quirks.html#dblquote">double-quoted string literal</a> misfeature for DDL statements,
such as CREATE TABLE and CREATE INDEX. The
default value of this setting is determined by the <a href="compile.html#dqs">-DSQLITE_DQS</a>
compile-time option.
</dd></p>
<p><a name="sqlitedbconfigtrustedschema"></a>
<dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</dt>
<dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
assume that database schemas are untainted by malicious content.
When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
takes additional defensive steps to protect the application from harm
including:
<ul>
<li> Prohibit the use of SQL functions inside triggers, views,
CHECK constraints, DEFAULT clauses, expression indexes,
partial indexes, or generated columns
unless those functions are tagged with <a href="#sqliteinnocuous">SQLITE_INNOCUOUS</a>.
<li> Prohibit the use of virtual tables inside of triggers or views
unless those virtual tables are tagged with <a href="#sqlitevtabinnocuous">SQLITE_VTAB_INNOCUOUS</a>.
</ul>
This setting defaults to "on" for legacy compatibility, however
all applications are advised to turn it off if possible. This setting
can also be controlled using the <a href="pragma.html#pragma_trusted_schema">PRAGMA trusted_schema</a> statement.
</dd></p>
<p><a name="sqlitedbconfiglegacyfileformat"></a>
<dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</dt>
<dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
the legacy file format flag. When activated, this flag causes all newly
created database file to have a schema format version number (the 4-byte
integer found at offset 44 into the database header) of 1. This in turn
means that the resulting database file will be readable and writable by
any SQLite version back to 3.0.0 (2004-06-18). Without this setting,
newly created databases are generally not understandable by SQLite versions
prior to 3.3.0 (2006-01-11). As these words are written, there
is now scarcely any need to generate database files that are compatible
all the way back to version 3.0.0, and so this setting is of little
practical use, but is provided so that SQLite can continue to claim the
ability to generate new database files that are compatible with version
3.0.0.
<p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
the <a href="lang_vacuum.html">VACUUM</a> command will fail with an obscure error when attempting to
process a table with generated columns and a descending index. This is
not considered a bug since SQLite versions 3.3.0 and earlier do not support
either generated columns or descending indexes.
</dd></p>
<p><a name="sqlitedbconfigstmtscanstatus"></a>
<dt>SQLITE_DBCONFIG_STMT_SCANSTATUS</dt>
<dd>The SQLITE_DBCONFIG_STMT_SCANSTATUS option is only useful in
SQLITE_ENABLE_STMT_SCANSTATUS builds. In this case, it sets or clears
a flag that enables collection of the sqlite3_stmt_scanstatus_v2()
statistics. For statistics to be collected, the flag must be set on
the database handle both when the SQL statement is prepared and when it
is stepped. The flag is set (collection of statistics is enabled)
by default. This option takes two arguments: an integer and a pointer to
an integer.. The first argument is 1, 0, or -1 to enable, disable, or
leave unchanged the statement scanstatus option. If the second argument
is not NULL, then the value of the statement scanstatus setting after
processing the first argument is written into the integer that the second
argument points to.
</dd></p>
<p><a name="sqlitedbconfigreversescanorder"></a>
<dt>SQLITE_DBCONFIG_REVERSE_SCANORDER</dt>
<dd>The SQLITE_DBCONFIG_REVERSE_SCANORDER option changes the default order
in which tables and indexes are scanned so that the scans start at the end
and work toward the beginning rather than starting at the beginning and
working toward the end. Setting SQLITE_DBCONFIG_REVERSE_SCANORDER is the
same as setting <a href="pragma.html#pragma_reverse_unordered_selects">PRAGMA reverse_unordered_selects</a>. This option takes
two arguments which are an integer and a pointer to an integer. The first
argument is 1, 0, or -1 to enable, disable, or leave unchanged the
reverse scan order flag, respectively. If the second argument is not NULL,
then 0 or 1 is written into the integer that the second argument points to
depending on if the reverse scan order flag is set after processing the
first argument.
</dd></p>
<p></dl>
</p><hr><a name="SQLITE_DENY"></a>
<h2>Authorizer Return Codes</h2>
</div>
<blockquote><pre>
#define SQLITE_DENY 1 /* Abort the SQL statement with an error */
#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
</pre></blockquote>
<p>
The <a href="#sqlite3_set_authorizer">authorizer callback function</a> must
return either <a href="#SQLITE_ABORT">SQLITE_OK</a> or one of these two constants in order
to signal SQLite whether or not the action is permitted. See the
<a href="#sqlite3_set_authorizer">authorizer documentation</a> for additional
information.</p>
<p>Note that SQLITE_IGNORE is also used as a <a href="#SQLITE_FAIL">conflict resolution mode</a>
returned from the <a href="#sqlite3_vtab_on_conflict">sqlite3_vtab_on_conflict()</a> interface.
</p><hr><a name="SQLITE_DESERIALIZE_FREEONCLOSE"></a>
<h2>Flags for sqlite3_deserialize()</h2>
</div>
<blockquote><pre>
#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */
#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */
</pre></blockquote>
<p>
The following are allowed values for 6th argument (the F argument) to
the <a href="#sqlite3_deserialize">sqlite3_deserialize(D,S,P,N,M,F)</a> interface.</p>
<p>The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
in the P argument is held in memory obtained from <a href="#sqlite3_free">sqlite3_malloc64()</a>
and that SQLite should take ownership of this memory and automatically
free it when it has finished using it. Without this flag, the caller
is responsible for freeing any dynamically allocated memory.</p>
<p>The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
grow the size of the database using calls to <a href="#sqlite3_free">sqlite3_realloc64()</a>. This
flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
Without this flag, the deserialized database cannot increase in size beyond
the number of bytes specified by the M parameter.</p>
<p>The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
should be treated as read-only.
</p><hr><a name="SQLITE_DETERMINISTIC"></a>
<h2>Function Flags</h2>
</div>
<blockquote><pre>
#define SQLITE_DETERMINISTIC 0x000000800
#define SQLITE_DIRECTONLY 0x000080000
#define SQLITE_SUBTYPE 0x000100000
#define SQLITE_INNOCUOUS 0x000200000
#define SQLITE_RESULT_SUBTYPE 0x001000000
</pre></blockquote>
<p>
These constants may be ORed together with the
<a href="#SQLITE_ANY">preferred text encoding</a> as the fourth argument
to <a href="#sqlite3_create_function">sqlite3_create_function()</a>, <a href="#sqlite3_create_function">sqlite3_create_function16()</a>, or
<a href="#sqlite3_create_function">sqlite3_create_function_v2()</a>.</p>
<p><dl>
<a name="sqlitedeterministic"></a>
<dt>SQLITE_DETERMINISTIC</dt><dd>
The SQLITE_DETERMINISTIC flag means that the new function always gives
the same output when the input parameters are the same.
The <a href="lang_corefunc.html#abs">abs() function</a> is deterministic, for example, but
<a href="lang_corefunc.html#randomblob">randomblob()</a> is not. Functions must
be deterministic in order to be used in certain contexts such as
with the WHERE clause of <a href="partialindex.html">partial indexes</a> or in <a href="gencol.html">generated columns</a>.
SQLite might also optimize deterministic functions by factoring them
out of inner loops.
</dd></p>
<p><a name="sqlitedirectonly"></a>
<dt>SQLITE_DIRECTONLY</dt><dd>
The SQLITE_DIRECTONLY flag means that the function may only be invoked
from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
schema structures such as <a href="lang_createtable.html#ckconst">CHECK constraints</a>, <a href="lang_createtable.html#dfltval">DEFAULT clauses</a>,
<a href="expridx.html">expression indexes</a>, <a href="partialindex.html">partial indexes</a>, or <a href="gencol.html">generated columns</a>.
<p>
The SQLITE_DIRECTONLY flag is recommended for any
<a href="appfunc.html">application-defined SQL function</a>
that has side-effects or that could potentially leak sensitive information.
This will prevent attacks in which an application is tricked
into using a database file that has had its schema surreptitiously
modified to invoke the application-defined function in ways that are
harmful.
<p>
Some people say it is good practice to set SQLITE_DIRECTONLY on all
<a href="appfunc.html">application-defined SQL functions</a>, regardless of whether or not they
are security sensitive, as doing so prevents those functions from being used
inside of the database schema, and thus ensures that the database
can be inspected and modified using generic tools (such as the <a href="cli.html">CLI</a>)
that do not have access to the application-defined functions.
</dd></p>
<p><a name="sqliteinnocuous"></a>
<dt>SQLITE_INNOCUOUS</dt><dd>
The SQLITE_INNOCUOUS flag means that the function is unlikely
to cause problems even if misused. An innocuous function should have
no side effects and should not depend on any values other than its
input parameters. The <a href="lang_corefunc.html#abs">abs() function</a> is an example of an
innocuous function.
The <a href="lang_corefunc.html#load_extension">load_extension() SQL function</a> is not innocuous because of its
side effects.
<p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
exactly the same. The <a href="lang_corefunc.html#random">random() function</a> is an example of a
function that is innocuous but not deterministic.
<p>Some heightened security settings
(<a href="#sqlitedbconfigtrustedschema">SQLITE_DBCONFIG_TRUSTED_SCHEMA</a> and <a href="pragma.html#pragma_trusted_schema">PRAGMA trusted_schema=OFF</a>)
disable the use of SQL functions inside views and triggers and in
schema structures such as <a href="lang_createtable.html#ckconst">CHECK constraints</a>, <a href="lang_createtable.html#dfltval">DEFAULT clauses</a>,
<a href="expridx.html">expression indexes</a>, <a href="partialindex.html">partial indexes</a>, and <a href="gencol.html">generated columns</a> unless
the function is tagged with SQLITE_INNOCUOUS. Most built-in functions
are innocuous. Developers are advised to avoid using the
SQLITE_INNOCUOUS flag for application-defined functions unless the
function has been carefully audited and found to be free of potentially
security-adverse side-effects and information-leaks.
</dd></p>
<p><a name="sqlitesubtype"></a>
<dt>SQLITE_SUBTYPE</dt><dd>
The SQLITE_SUBTYPE flag indicates to SQLite that a function might call
<a href="#sqlite3_value_subtype">sqlite3_value_subtype()</a> to inspect the sub-types of its arguments.
This flag instructs SQLite to omit some corner-case optimizations that
might disrupt the operation of the <a href="#sqlite3_value_subtype">sqlite3_value_subtype()</a> function,
causing it to return zero rather than the correct subtype().
SQL functions that invokes <a href="#sqlite3_value_subtype">sqlite3_value_subtype()</a> should have this
property. If the SQLITE_SUBTYPE property is omitted, then the return
value from <a href="#sqlite3_value_subtype">sqlite3_value_subtype()</a> might sometimes be zero even though
a non-zero subtype was specified by the function argument expression.</p>
<p><a name="sqliteresultsubtype"></a>
<dt>SQLITE_RESULT_SUBTYPE</dt><dd>
The SQLITE_RESULT_SUBTYPE flag indicates to SQLite that a function might call
<a href="#sqlite3_result_subtype">sqlite3_result_subtype()</a> to cause a sub-type to be associated with its
result.
Every function that invokes <a href="#sqlite3_result_subtype">sqlite3_result_subtype()</a> should have this
property. If it does not, then the call to <a href="#sqlite3_result_subtype">sqlite3_result_subtype()</a>
might become a no-op if the function is used as term in an
<a href="expridx.html">expression index</a>. On the other hand, SQL functions that never invoke
<a href="#sqlite3_result_subtype">sqlite3_result_subtype()</a> should avoid setting this property, as the
purpose of this property is to disable certain optimizations that are
incompatible with subtypes.
</dd>
</dl>
</p><hr><a name="SQLITE_FAIL"></a>
<h2>Conflict resolution modes</h2>
</div>
<blockquote><pre>
#define SQLITE_ROLLBACK 1
/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
#define SQLITE_FAIL 3
/* #define SQLITE_ABORT 4 // Also an error code */
#define SQLITE_REPLACE 5
</pre></blockquote>
<p>
These constants are returned by <a href="#sqlite3_vtab_on_conflict">sqlite3_vtab_on_conflict()</a> to
inform a <a href="vtab.html">virtual table</a> implementation what the <a href="lang_conflict.html">ON CONFLICT</a> mode
is for the SQL statement being evaluated.</p>
<p>Note that the <a href="#SQLITE_DENY">SQLITE_IGNORE</a> constant is also used as a potential
return value from the <a href="#sqlite3_set_authorizer">sqlite3_set_authorizer()</a> callback and that
<a href="#SQLITE_ABORT">SQLITE_ABORT</a> is also a <a href="rescode.html">result code</a>.
</p><hr><a name="SQLITE_FCNTL_BEGIN_ATOMIC_WRITE"></a>
<h2>Standard File Control Opcodes</h2>
</div>
<blockquote><pre>
#define SQLITE_FCNTL_LOCKSTATE 1
#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2
#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3
#define SQLITE_FCNTL_LAST_ERRNO 4
#define SQLITE_FCNTL_SIZE_HINT 5
#define SQLITE_FCNTL_CHUNK_SIZE 6
#define SQLITE_FCNTL_FILE_POINTER 7
#define SQLITE_FCNTL_SYNC_OMITTED 8
#define SQLITE_FCNTL_WIN32_AV_RETRY 9
#define SQLITE_FCNTL_PERSIST_WAL 10
#define SQLITE_FCNTL_OVERWRITE 11
#define SQLITE_FCNTL_VFSNAME 12
#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
#define SQLITE_FCNTL_PRAGMA 14
#define SQLITE_FCNTL_BUSYHANDLER 15
#define SQLITE_FCNTL_TEMPFILENAME 16
#define SQLITE_FCNTL_MMAP_SIZE 18
#define SQLITE_FCNTL_TRACE 19
#define SQLITE_FCNTL_HAS_MOVED 20
#define SQLITE_FCNTL_SYNC 21
#define SQLITE_FCNTL_COMMIT_PHASETWO 22
#define SQLITE_FCNTL_WIN32_SET_HANDLE 23
#define SQLITE_FCNTL_WAL_BLOCK 24
#define SQLITE_FCNTL_ZIPVFS 25
#define SQLITE_FCNTL_RBU 26
#define SQLITE_FCNTL_VFS_POINTER 27
#define SQLITE_FCNTL_JOURNAL_POINTER 28
#define SQLITE_FCNTL_WIN32_GET_HANDLE 29
#define SQLITE_FCNTL_PDB 30
#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31
#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32
#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33
#define SQLITE_FCNTL_LOCK_TIMEOUT 34
#define SQLITE_FCNTL_DATA_VERSION 35
#define SQLITE_FCNTL_SIZE_LIMIT 36
#define SQLITE_FCNTL_CKPT_DONE 37
#define SQLITE_FCNTL_RESERVE_BYTES 38
#define SQLITE_FCNTL_CKPT_START 39
#define SQLITE_FCNTL_EXTERNAL_READER 40
#define SQLITE_FCNTL_CKSM_FILE 41
#define SQLITE_FCNTL_RESET_CACHE 42
</pre></blockquote>
<p>
These integer constants are opcodes for the xFileControl method
of the <a href="#sqlite3_io_methods">sqlite3_io_methods</a> object and for the <a href="#sqlite3_file_control">sqlite3_file_control()</a>
interface.</p>
<p><ul>
<li><a name="sqlitefcntllockstate"></a>
The <a href="#sqlitefcntllockstate">SQLITE_FCNTL_LOCKSTATE</a> opcode is used for debugging. This
opcode causes the xFileControl method to write the current state of
the lock (one of <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_NONE</a>, <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_SHARED</a>,
<a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_RESERVED</a>, <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_PENDING</a>, or <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_EXCLUSIVE</a>)
into an integer that the pArg argument points to.
This capability is only available if SQLite is compiled with <a href="compile.html#debug">SQLITE_DEBUG</a>.</p>
<p><li><a name="sqlitefcntlsizehint"></a>
The <a href="#sqlitefcntlsizehint">SQLITE_FCNTL_SIZE_HINT</a> opcode is used by SQLite to give the VFS
layer a hint of how large the database file will grow to be during the
current transaction. This hint is not guaranteed to be accurate but it
is often close. The underlying VFS might choose to preallocate database
file space based on this hint in order to help writes to the database
file run faster.</p>
<p><li><a name="sqlitefcntlsizelimit"></a>
The <a href="#sqlitefcntlsizelimit">SQLITE_FCNTL_SIZE_LIMIT</a> opcode is used by in-memory VFS that
implements <a href="#sqlite3_deserialize">sqlite3_deserialize()</a> to set an upper bound on the size
of the in-memory database. The argument is a pointer to a <a href="#sqlite3_int64">sqlite3_int64</a>.
If the integer pointed to is negative, then it is filled in with the
current limit. Otherwise the limit is set to the larger of the value
of the integer pointed to and the current database size. The integer
pointed to is set to the new limit.</p>
<p><li><a name="sqlitefcntlchunksize"></a>
The <a href="#sqlitefcntlchunksize">SQLITE_FCNTL_CHUNK_SIZE</a> opcode is used to request that the VFS
extends and truncates the database file in chunks of a size specified
by the user. The fourth argument to <a href="#sqlite3_file_control">sqlite3_file_control()</a> should
point to an integer (type int) containing the new chunk-size to use
for the nominated database. Allocating database file space in large
chunks (say 1MB at a time), may reduce file-system fragmentation and
improve performance on some systems.</p>
<p><li><a name="sqlitefcntlfilepointer"></a>
The <a href="#sqlitefcntlfilepointer">SQLITE_FCNTL_FILE_POINTER</a> opcode is used to obtain a pointer
to the <a href="#sqlite3_file">sqlite3_file</a> object associated with a particular database
connection. See also <a href="#sqlitefcntljournalpointer">SQLITE_FCNTL_JOURNAL_POINTER</a>.</p>
<p><li><a name="sqlitefcntljournalpointer"></a>
The <a href="#sqlitefcntljournalpointer">SQLITE_FCNTL_JOURNAL_POINTER</a> opcode is used to obtain a pointer
to the <a href="#sqlite3_file">sqlite3_file</a> object associated with the journal file (either
the <a href="lockingv3.html#rollback">rollback journal</a> or the <a href="wal.html">write-ahead log</a>) for a particular database
connection. See also <a href="#sqlitefcntlfilepointer">SQLITE_FCNTL_FILE_POINTER</a>.</p>
<p><li><a name="sqlitefcntlsyncomitted"></a>
No longer in use.</p>
<p><li><a name="sqlitefcntlsync"></a>
The <a href="#sqlitefcntlsync">SQLITE_FCNTL_SYNC</a> opcode is generated internally by SQLite and
sent to the VFS immediately before the xSync method is invoked on a
database file descriptor. Or, if the xSync method is not invoked
because the user has configured SQLite with
<a href="pragma.html#pragma_synchronous">PRAGMA synchronous=OFF</a> it is invoked in place
of the xSync method. In most cases, the pointer argument passed with
this file-control is NULL. However, if the database file is being synced
as part of a multi-database commit, the argument points to a nul-terminated
string containing the transactions super-journal file name. VFSes that
do not need this signal should silently ignore this opcode. Applications
should not call <a href="#sqlite3_file_control">sqlite3_file_control()</a> with this opcode as doing so may
disrupt the operation of the specialized VFSes that do require it.</p>
<p><li><a name="sqlitefcntlcommitphasetwo"></a>
The <a href="#sqlitefcntlcommitphasetwo">SQLITE_FCNTL_COMMIT_PHASETWO</a> opcode is generated internally by SQLite
and sent to the VFS after a transaction has been committed immediately
but before the database is unlocked. VFSes that do not need this signal
should silently ignore this opcode. Applications should not call
<a href="#sqlite3_file_control">sqlite3_file_control()</a> with this opcode as doing so may disrupt the
operation of the specialized VFSes that do require it.</p>
<p><li><a name="sqlitefcntlwin32avretry"></a>
The <a href="#sqlitefcntlwin32avretry">SQLITE_FCNTL_WIN32_AV_RETRY</a> opcode is used to configure automatic
retry counts and intervals for certain disk I/O operations for the
windows <a href="vfs.html">VFS</a> in order to provide robustness in the presence of
anti-virus programs. By default, the windows VFS will retry file read,
file write, and file delete operations up to 10 times, with a delay
of 25 milliseconds before the first retry and with the delay increasing
by an additional 25 milliseconds with each subsequent retry. This
opcode allows these two values (10 retries and 25 milliseconds of delay)
to be adjusted. The values are changed for all database connections
within the same process. The argument is a pointer to an array of two
integers where the first integer is the new retry count and the second
integer is the delay. If either integer is negative, then the setting
is not changed but instead the prior value of that setting is written
into the array entry, allowing the current retry settings to be
interrogated. The zDbName parameter is ignored.</p>
<p><li><a name="sqlitefcntlpersistwal"></a>
The <a href="#sqlitefcntlpersistwal">SQLITE_FCNTL_PERSIST_WAL</a> opcode is used to set or query the
persistent <a href="wal.html">Write Ahead Log</a> setting. By default, the auxiliary
write ahead log (<a href="wal.html#walfile">WAL file</a>) and shared memory
files used for transaction control
are automatically deleted when the latest connection to the database
closes. Setting persistent WAL mode causes those files to persist after
close. Persisting the files is useful when other processes that do not
have write permission on the directory containing the database file want
to read the database file, as the WAL and shared memory files must exist
in order for the database to be readable. The fourth parameter to
<a href="#sqlite3_file_control">sqlite3_file_control()</a> for this opcode should be a pointer to an integer.
That integer is 0 to disable persistent WAL mode or 1 to enable persistent
WAL mode. If the integer is -1, then it is overwritten with the current
WAL persistence setting.</p>
<p><li><a name="sqlitefcntlpowersafeoverwrite"></a>
The <a href="#sqlitefcntlpowersafeoverwrite">SQLITE_FCNTL_POWERSAFE_OVERWRITE</a> opcode is used to set or query the
persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
determines the <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_POWERSAFE_OVERWRITE</a> bit of the
xDeviceCharacteristics methods. The fourth parameter to
<a href="#sqlite3_file_control">sqlite3_file_control()</a> for this opcode should be a pointer to an integer.
That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
mode. If the integer is -1, then it is overwritten with the current
zero-damage mode setting.</p>
<p><li><a name="sqlitefcntloverwrite"></a>
The <a href="#sqlitefcntloverwrite">SQLITE_FCNTL_OVERWRITE</a> opcode is invoked by SQLite after opening
a write transaction to indicate that, unless it is rolled back for some
reason, the entire database file will be overwritten by the current
transaction. This is used by VACUUM operations.</p>
<p><li><a name="sqlitefcntlvfsname"></a>
The <a href="#sqlitefcntlvfsname">SQLITE_FCNTL_VFSNAME</a> opcode can be used to obtain the names of
all <a href="vfs.html">VFSes</a> in the VFS stack. The names are of all VFS shims and the
final bottom-level VFS are written into memory obtained from
<a href="#sqlite3_free">sqlite3_malloc()</a> and the result is stored in the char* variable
that the fourth parameter of <a href="#sqlite3_file_control">sqlite3_file_control()</a> points to.
The caller is responsible for freeing the memory when done. As with
all file-control actions, there is no guarantee that this will actually
do anything. Callers should initialize the char* variable to a NULL
pointer in case this file-control is not implemented. This file-control
is intended for diagnostic use only.</p>
<p><li><a name="sqlitefcntlvfspointer"></a>
The <a href="#sqlitefcntlvfspointer">SQLITE_FCNTL_VFS_POINTER</a> opcode finds a pointer to the top-level
<a href="vfs.html">VFSes</a> currently in use. The argument X in
sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
of type "<a href="#sqlite3_vfs">sqlite3_vfs</a> **". This opcodes will set *X
to a pointer to the top-level VFS.
When there are multiple VFS shims in the stack, this opcode finds the
upper-most shim only.</p>
<p><li><a name="sqlitefcntlpragma"></a>
Whenever a <a href="pragma.html#syntax">PRAGMA</a> statement is parsed, an <a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a>
file control is sent to the open <a href="#sqlite3_file">sqlite3_file</a> object corresponding
to the database file to which the pragma statement refers. The argument
to the <a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a> file control is an array of
pointers to strings (char**) in which the second element of the array
is the name of the pragma and the third element is the argument to the
pragma or NULL if the pragma has no argument. The handler for an
<a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a> file control can optionally make the first element
of the char** argument point to a string obtained from <a href="#sqlite3_mprintf">sqlite3_mprintf()</a>
or the equivalent and that string will become the result of the pragma or
the error message if the pragma fails. If the
<a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a> file control returns <a href="#SQLITE_ABORT">SQLITE_NOTFOUND</a>, then normal
<a href="pragma.html#syntax">PRAGMA</a> processing continues. If the <a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a>
file control returns <a href="#SQLITE_ABORT">SQLITE_OK</a>, then the parser assumes that the
VFS has handled the PRAGMA itself and the parser generates a no-op
prepared statement if result string is NULL, or that returns a copy
of the result string if the string is non-NULL.
If the <a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a> file control returns
any result code other than <a href="#SQLITE_ABORT">SQLITE_OK</a> or <a href="#SQLITE_ABORT">SQLITE_NOTFOUND</a>, that means
that the VFS encountered an error while handling the <a href="pragma.html#syntax">PRAGMA</a> and the
compilation of the PRAGMA fails with an error. The <a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a>
file control occurs at the beginning of pragma statement analysis and so
it is able to override built-in <a href="pragma.html#syntax">PRAGMA</a> statements.</p>
<p><li><a name="sqlitefcntlbusyhandler"></a>
The <a href="#sqlitefcntlbusyhandler">SQLITE_FCNTL_BUSYHANDLER</a>
file-control may be invoked by SQLite on the database file handle
shortly after it is opened in order to provide a custom VFS with access
to the connection's busy-handler callback. The argument is of type (void**)
- an array of two (void *) values. The first (void *) actually points
to a function of type (int (*)(void *)). In order to invoke the connection's
busy-handler, this function should be invoked with the second (void *) in
the array as the only argument. If it returns non-zero, then the operation
should be retried. If it returns zero, the custom VFS should abandon the
current operation.</p>
<p><li><a name="sqlitefcntltempfilename"></a>
Applications can invoke the <a href="#sqlitefcntltempfilename">SQLITE_FCNTL_TEMPFILENAME</a> file-control
to have SQLite generate a
temporary filename using the same algorithm that is followed to generate
temporary filenames for TEMP tables and other internal uses. The
argument should be a char** which will be filled with the filename
written into memory obtained from <a href="#sqlite3_free">sqlite3_malloc()</a>. The caller should
invoke <a href="#sqlite3_free">sqlite3_free()</a> on the result to avoid a memory leak.</p>
<p><li><a name="sqlitefcntlmmapsize"></a>
The <a href="#sqlitefcntlmmapsize">SQLITE_FCNTL_MMAP_SIZE</a> file control is used to query or set the
maximum number of bytes that will be used for memory-mapped I/O.
The argument is a pointer to a value of type sqlite3_int64 that
is an advisory maximum number of bytes in the file to memory map. The
pointer is overwritten with the old value. The limit is not changed if
the value originally pointed to is negative, and so the current limit
can be queried by passing in a pointer to a negative number. This
file-control is used internally to implement <a href="pragma.html#pragma_mmap_size">PRAGMA mmap_size</a>.</p>
<p><li><a name="sqlitefcntltrace"></a>
The <a href="#sqlitefcntltrace">SQLITE_FCNTL_TRACE</a> file control provides advisory information
to the VFS about what the higher layers of the SQLite stack are doing.
This file control is used by some VFS activity tracing <a href="vfs.html#shim">shims</a>.
The argument is a zero-terminated string. Higher layers in the
SQLite stack may generate instances of this file control if
the <a href="compile.html#use_fcntl_trace">SQLITE_USE_FCNTL_TRACE</a> compile-time option is enabled.</p>
<p><li><a name="sqlitefcntlhasmoved"></a>
The <a href="#sqlitefcntlhasmoved">SQLITE_FCNTL_HAS_MOVED</a> file control interprets its argument as a
pointer to an integer and it writes a boolean into that integer depending
on whether or not the file has been renamed, moved, or deleted since it
was first opened.</p>
<p><li><a name="sqlitefcntlwin32gethandle"></a>
The <a href="#sqlitefcntlwin32gethandle">SQLITE_FCNTL_WIN32_GET_HANDLE</a> opcode can be used to obtain the
underlying native file handle associated with a file handle. This file
control interprets its argument as a pointer to a native file handle and
writes the resulting value there.</p>
<p><li><a name="sqlitefcntlwin32sethandle"></a>
The <a href="#sqlitefcntlwin32sethandle">SQLITE_FCNTL_WIN32_SET_HANDLE</a> opcode is used for debugging. This
opcode causes the xFileControl method to swap the file handle with the one
pointed to by the pArg argument. This capability is used during testing
and only needs to be supported when SQLITE_TEST is defined.</p>
<p><li><a name="sqlitefcntlwalblock"></a>
The <a href="#sqlitefcntlwalblock">SQLITE_FCNTL_WAL_BLOCK</a> is a signal to the VFS layer that it might
be advantageous to block on the next WAL lock if the lock is not immediately
available. The WAL subsystem issues this signal during rare
circumstances in order to fix a problem with priority inversion.
Applications should <em>not</em> use this file-control.</p>
<p><li><a name="sqlitefcntlzipvfs"></a>
The <a href="#sqlitefcntlzipvfs">SQLITE_FCNTL_ZIPVFS</a> opcode is implemented by zipvfs only. All other
VFS should return SQLITE_NOTFOUND for this opcode.</p>
<p><li><a name="sqlitefcntlrbu"></a>
The <a href="#sqlitefcntlrbu">SQLITE_FCNTL_RBU</a> opcode is implemented by the special VFS used by
the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
this opcode.</p>
<p><li><a name="sqlitefcntlbeginatomicwrite"></a>
If the <a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a> opcode returns SQLITE_OK, then
the file descriptor is placed in "batch write mode", which
means all subsequent write operations will be deferred and done
atomically at the next <a href="#sqlitefcntlcommitatomicwrite">SQLITE_FCNTL_COMMIT_ATOMIC_WRITE</a>. Systems
that do not support batch atomic writes will return SQLITE_NOTFOUND.
Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
the closing <a href="#sqlitefcntlcommitatomicwrite">SQLITE_FCNTL_COMMIT_ATOMIC_WRITE</a> or
<a href="#sqlitefcntlrollbackatomicwrite">SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE</a>, SQLite will make
no VFS interface calls on the same <a href="#sqlite3_file">sqlite3_file</a> file descriptor
except for calls to the xWrite method and the xFileControl method
with <a href="#sqlitefcntlsizehint">SQLITE_FCNTL_SIZE_HINT</a>.</p>
<p><li><a name="sqlitefcntlcommitatomicwrite"></a>
The <a href="#sqlitefcntlcommitatomicwrite">SQLITE_FCNTL_COMMIT_ATOMIC_WRITE</a> opcode causes all write
operations since the previous successful call to
<a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a> to be performed atomically.
This file control returns <a href="#SQLITE_ABORT">SQLITE_OK</a> if and only if the writes were
all performed successfully and have been committed to persistent storage.
Regardless of whether or not it is successful, this file control takes
the file descriptor out of batch write mode so that all subsequent
write operations are independent.
SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
a prior successful call to <a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a>.</p>
<p><li><a name="sqlitefcntlrollbackatomicwrite"></a>
The <a href="#sqlitefcntlrollbackatomicwrite">SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE</a> opcode causes all write
operations since the previous successful call to
<a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a> to be rolled back.
This file control takes the file descriptor out of batch write mode
so that all subsequent write operations are independent.
SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
a prior successful call to <a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a>.</p>
<p><li><a name="sqlitefcntllocktimeout"></a>
The <a href="#sqlitefcntllocktimeout">SQLITE_FCNTL_LOCK_TIMEOUT</a> opcode is used to configure a VFS
to block for up to M milliseconds before failing when attempting to
obtain a file lock using the xLock or xShmLock methods of the VFS.
The parameter is a pointer to a 32-bit signed integer that contains
the value that M is to be set to. Before returning, the 32-bit signed
integer is overwritten with the previous value of M.</p>
<p><li><a name="sqlitefcntldataversion"></a>
The <a href="#sqlitefcntldataversion">SQLITE_FCNTL_DATA_VERSION</a> opcode is used to detect changes to
a database file. The argument is a pointer to a 32-bit unsigned integer.
The "data version" for the pager is written into the pointer. The
"data version" changes whenever any change occurs to the corresponding
database file, either through SQL statements on the same database
connection or through transactions committed by separate database
connections possibly in other processes. The <a href="#sqlite3_total_changes">sqlite3_total_changes()</a>
interface can be used to find if any database on the connection has changed,
but that interface responds to changes on TEMP as well as MAIN and does
not provide a mechanism to detect changes to MAIN only. Also, the
<a href="#sqlite3_total_changes">sqlite3_total_changes()</a> interface responds to internal changes only and
omits changes made by other database connections. The
<a href="pragma.html#pragma_data_version">PRAGMA data_version</a> command provides a mechanism to detect changes to
a single attached database that occur due to other database connections,
but omits changes implemented by the database connection on which it is
called. This file control is the only mechanism to detect changes that
happen either internally or externally and that are associated with
a particular attached database.</p>
<p><li><a name="sqlitefcntlckptstart"></a>
The <a href="#sqlitefcntlckptstart">SQLITE_FCNTL_CKPT_START</a> opcode is invoked from within a checkpoint
in wal mode before the client starts to copy pages from the wal
file to the database file.</p>
<p><li><a name="sqlitefcntlckptdone"></a>
The <a href="#sqlitefcntlckptdone">SQLITE_FCNTL_CKPT_DONE</a> opcode is invoked from within a checkpoint
in wal mode after the client has finished copying pages from the wal
file to the database file, but before the *-shm file is updated to
record the fact that the pages have been checkpointed.</p>
<p><li><a name="sqlitefcntlexternalreader"></a>
The EXPERIMENTAL <a href="#sqlitefcntlexternalreader">SQLITE_FCNTL_EXTERNAL_READER</a> opcode is used to detect
whether or not there is a database client in another process with a wal-mode
transaction open on the database or not. It is only available on unix.The
(void*) argument passed with this file-control should be a pointer to a
value of type (int). The integer value is set to 1 if the database is a wal
mode database and there exists at least one client in another process that
currently has an SQL transaction open on the database. It is set to 0 if
the database is not a wal-mode db, or if there is no such connection in any
other process. This opcode cannot be used to detect transactions opened
by clients within the current process, only within other processes.</p>
<p><li><a name="sqlitefcntlcksmfile"></a>
The <a href="#sqlitefcntlcksmfile">SQLITE_FCNTL_CKSM_FILE</a> opcode is for use internally by the
<a href="cksumvfs.html">checksum VFS shim</a> only.</p>
<p><li><a name="sqlitefcntlresetcache"></a>
If there is currently no transaction open on the database, and the
database is not a temp db, then the <a href="#sqlitefcntlresetcache">SQLITE_FCNTL_RESET_CACHE</a> file-control
purges the contents of the in-memory page cache. If there is an open
transaction, or if the db is a temp-db, this opcode is a no-op, not an error.
</ul>
</p><hr><a name="SQLITE_INDEX_CONSTRAINT_EQ"></a>
<h2>Virtual Table Constraint Operator Codes</h2>
</div>
<blockquote><pre>
#define SQLITE_INDEX_CONSTRAINT_EQ 2
#define SQLITE_INDEX_CONSTRAINT_GT 4
#define SQLITE_INDEX_CONSTRAINT_LE 8
#define SQLITE_INDEX_CONSTRAINT_LT 16
#define SQLITE_INDEX_CONSTRAINT_GE 32
#define SQLITE_INDEX_CONSTRAINT_MATCH 64
#define SQLITE_INDEX_CONSTRAINT_LIKE 65
#define SQLITE_INDEX_CONSTRAINT_GLOB 66
#define SQLITE_INDEX_CONSTRAINT_REGEXP 67
#define SQLITE_INDEX_CONSTRAINT_NE 68
#define SQLITE_INDEX_CONSTRAINT_ISNOT 69
#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
#define SQLITE_INDEX_CONSTRAINT_ISNULL 71
#define SQLITE_INDEX_CONSTRAINT_IS 72
#define SQLITE_INDEX_CONSTRAINT_LIMIT 73
#define SQLITE_INDEX_CONSTRAINT_OFFSET 74
#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150
</pre></blockquote>
<p>
These macros define the allowed values for the
<a href="#sqlite3_index_info">sqlite3_index_info</a>.aConstraint[].op field. Each value represents
an operator that is part of a constraint term in the WHERE clause of
a query that uses a <a href="vtab.html">virtual table</a>.</p>
<p>The left-hand operand of the operator is given by the corresponding
aConstraint[].iColumn field. An iColumn of -1 indicates the left-hand
operand is the rowid.
The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
operators have no left-hand operand, and so for those operators the
corresponding aConstraint[].iColumn is meaningless and should not be
used.</p>
<p>All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
value 255 are reserved to represent functions that are overloaded
by the <a href="vtab.html#xfindfunction">xFindFunction method</a> of the virtual table
implementation.</p>
<p>The right-hand operands for each constraint might be accessible using
the <a href="#sqlite3_vtab_rhs_value">sqlite3_vtab_rhs_value()</a> interface. Usually the right-hand
operand is only available if it appears as a single constant literal
in the input SQL. If the right-hand operand is another column or an
expression (even a constant expression) or a parameter, then the
sqlite3_vtab_rhs_value() probably will not be able to extract it.
The SQLITE_INDEX_CONSTRAINT_ISNULL and
SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
and hence calls to sqlite3_vtab_rhs_value() for those operators will
always return SQLITE_NOTFOUND.</p>
<p>The collating sequence to be used for comparison can be found using
the <a href="#sqlite3_vtab_collation">sqlite3_vtab_collation()</a> interface. For most real-world virtual
tables, the collating sequence of constraints does not matter (for example
because the constraints are numeric) and so the sqlite3_vtab_collation()
interface is not commonly needed.
</p><hr><a name="SQLITE_IOCAP_ATOMIC"></a>
<h2>Device Characteristics</h2>
</div>
<blockquote><pre>
#define SQLITE_IOCAP_ATOMIC 0x00000001
#define SQLITE_IOCAP_ATOMIC512 0x00000002
#define SQLITE_IOCAP_ATOMIC1K 0x00000004
#define SQLITE_IOCAP_ATOMIC2K 0x00000008
#define SQLITE_IOCAP_ATOMIC4K 0x00000010
#define SQLITE_IOCAP_ATOMIC8K 0x00000020
#define SQLITE_IOCAP_ATOMIC16K 0x00000040
#define SQLITE_IOCAP_ATOMIC32K 0x00000080
#define SQLITE_IOCAP_ATOMIC64K 0x00000100
#define SQLITE_IOCAP_SAFE_APPEND 0x00000200
#define SQLITE_IOCAP_SEQUENTIAL 0x00000400
#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
#define SQLITE_IOCAP_IMMUTABLE 0x00002000
#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000
</pre></blockquote>
<p>
The xDeviceCharacteristics method of the <a href="#sqlite3_io_methods">sqlite3_io_methods</a>
object returns an integer which is a vector of these
bit values expressing I/O characteristics of the mass storage
device that holds the file that the <a href="#sqlite3_io_methods">sqlite3_io_methods</a>
refers to.</p>
<p>The SQLITE_IOCAP_ATOMIC property means that all writes of
any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
mean that writes of blocks that are nnn bytes in size and
are aligned to an address which is an integer multiple of
nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
that when data is appended to a file, the data is appended
first then the size of the file is extended, never the other
way around. The SQLITE_IOCAP_SEQUENTIAL property means that
information is written to disk in the same order as calls
to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
after reboot following a crash or power loss, the only bytes in a
file that were written at the application level might have changed
and that adjacent bytes, even bytes within the same sector are
guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
flag indicates that a file cannot be deleted when open. The
SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
read-only media and cannot be changed even by processes with
elevated privileges.</p>
<p>The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
filesystem supports doing multiple write operations atomically when those
write operations are bracketed by <a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a> and
<a href="#sqlitefcntlcommitatomicwrite">SQLITE_FCNTL_COMMIT_ATOMIC_WRITE</a>.
</p><hr><a name="SQLITE_LOCK_EXCLUSIVE"></a>
<h2>File Locking Levels</h2>
</div>
<blockquote><pre>
#define SQLITE_LOCK_NONE 0 /* xUnlock() only */
#define SQLITE_LOCK_SHARED 1 /* xLock() or xUnlock() */
#define SQLITE_LOCK_RESERVED 2 /* xLock() only */
#define SQLITE_LOCK_PENDING 3 /* xLock() only */
#define SQLITE_LOCK_EXCLUSIVE 4 /* xLock() only */
</pre></blockquote>
<p>
SQLite uses one of these integer values as the second
argument to calls it makes to the xLock() and xUnlock() methods
of an <a href="#sqlite3_io_methods">sqlite3_io_methods</a> object. These values are ordered from
lest restrictive to most restrictive.</p>
<p>The argument to xLock() is always SHARED or higher. The argument to
xUnlock is either SHARED or NONE.
</p><hr><a name="SQLITE_MUTEX_FAST"></a>
<h2>Mutex Types</h2>
</div>
<blockquote><pre>
#define SQLITE_MUTEX_FAST 0
#define SQLITE_MUTEX_RECURSIVE 1
#define SQLITE_MUTEX_STATIC_MAIN 2
#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */
#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
</pre></blockquote>
<p>
The <a href="#sqlite3_mutex_alloc">sqlite3_mutex_alloc()</a> interface takes a single argument
which is one of these integer constants.</p>
<p>The set of static mutexes may change from one SQLite release to the
next. Applications that override the built-in mutex logic must be
prepared to accommodate additional static mutexes.
</p><hr><a name="SQLITE_OPEN_AUTOPROXY"></a>
<h2>Flags For File Open Operations</h2>
</div>
<blockquote><pre>
#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
#define SQLITE_OPEN_SUPER_JOURNAL 0x00004000 /* VFS only */
#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
#define SQLITE_OPEN_NOFOLLOW 0x01000000 /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_EXRESCODE 0x02000000 /* Extended result codes */
</pre></blockquote>
<p>
These bit values are intended for use in the
3rd parameter to the <a href="#sqlite3_open">sqlite3_open_v2()</a> interface and
in the 4th parameter to the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a> method.</p>
<p>Only those flags marked as "Ok for sqlite3_open_v2()" may be
used as the third argument to the <a href="#sqlite3_open">sqlite3_open_v2()</a> interface.
The other flags have historically been ignored by sqlite3_open_v2(),
though future versions of SQLite might change so that an error is
raised if any of the disallowed bits are passed into sqlite3_open_v2().
Applications should not depend on the historical behavior.</p>
<p>Note in particular that passing the SQLITE_OPEN_EXCLUSIVE flag into
<a href="#sqlite3_open">sqlite3_open_v2()</a> does *not* cause the underlying database file
to be opened using O_EXCL. Passing SQLITE_OPEN_EXCLUSIVE into
<a href="#sqlite3_open">sqlite3_open_v2()</a> has historically be a no-op and might become an
error in future versions of SQLite.
</p><hr><a name="SQLITE_PREPARE_NORMALIZE"></a>
<h2>Prepare Flags</h2>
</div>
<blockquote><pre>
#define SQLITE_PREPARE_PERSISTENT 0x01
#define SQLITE_PREPARE_NORMALIZE 0x02
#define SQLITE_PREPARE_NO_VTAB 0x04
</pre></blockquote>
<p>
These constants define various flags that can be passed into
"prepFlags" parameter of the <a href="#sqlite3_prepare">sqlite3_prepare_v3()</a> and
<a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a> interfaces.</p>
<p>New flags may be added in future releases of SQLite.</p>
<p><dl>
<a name="sqlitepreparepersistent"></a>
<dt>SQLITE_PREPARE_PERSISTENT</dt>
<dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
that the prepared statement will be retained for a long time and
probably reused many times. Without this flag, <a href="#sqlite3_prepare">sqlite3_prepare_v3()</a>
and <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a> assume that the prepared statement will
be used just once or at most a few times and then destroyed using
<a href="#sqlite3_finalize">sqlite3_finalize()</a> relatively soon. The current implementation acts
on this hint by avoiding the use of <a href="malloc.html#lookaside">lookaside memory</a> so as not to
deplete the limited store of lookaside memory. Future versions of
SQLite may act on this hint differently.</p>
<p><a name="sqlitepreparenormalize"></a>
<dt>SQLITE_PREPARE_NORMALIZE</dt>
<dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
to be required for any prepared statement that wanted to use the
<a href="#sqlite3_expanded_sql">sqlite3_normalized_sql()</a> interface. However, the
<a href="#sqlite3_expanded_sql">sqlite3_normalized_sql()</a> interface is now available to all
prepared statements, regardless of whether or not they use this
flag.</p>
<p><a name="sqlitepreparenovtab"></a>
<dt>SQLITE_PREPARE_NO_VTAB</dt>
<dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
to return an error (error code SQLITE_ERROR) if the statement uses
any virtual tables.
</dl>
</p><hr><a name="SQLITE_SCANSTAT_COMPLEX"></a>
<h2>Prepared Statement Scan Status</h2>
</div>
<blockquote><pre>
#define SQLITE_SCANSTAT_COMPLEX 0x0001
</pre></blockquote>
<p></p><hr><a name="SQLITE_SCANSTAT_EST"></a>
<h2>Prepared Statement Scan Status Opcodes</h2>
</div>
<blockquote><pre>
#define SQLITE_SCANSTAT_NLOOP 0
#define SQLITE_SCANSTAT_NVISIT 1
#define SQLITE_SCANSTAT_EST 2
#define SQLITE_SCANSTAT_NAME 3
#define SQLITE_SCANSTAT_EXPLAIN 4
#define SQLITE_SCANSTAT_SELECTID 5
#define SQLITE_SCANSTAT_PARENTID 6
#define SQLITE_SCANSTAT_NCYCLE 7
</pre></blockquote>
<p>
The following constants can be used for the T parameter to the
<a href="#sqlite3_stmt_scanstatus">sqlite3_stmt_scanstatus(S,X,T,V)</a> interface. Each constant designates a
different metric for sqlite3_stmt_scanstatus() to return.</p>
<p>When the value returned to V is a string, space to hold that string is
managed by the prepared statement S and will be automatically freed when
S is finalized.</p>
<p>Not all values are available for all query elements. When a value is
not available, the output variable is set to -1 if the value is numeric,
or to NULL if it is a string (SQLITE_SCANSTAT_NAME).</p>
<p><dl>
<a name="sqlitescanstatnloop"></a>
<dt>SQLITE_SCANSTAT_NLOOP</dt>
<dd>The <a href="#sqlite3_int64">sqlite3_int64</a> variable pointed to by the V parameter will be
set to the total number of times that the X-th loop has run.</dd></p>
<p><a name="sqlitescanstatnvisit"></a>
<dt>SQLITE_SCANSTAT_NVISIT</dt>
<dd>The <a href="#sqlite3_int64">sqlite3_int64</a> variable pointed to by the V parameter will be set
to the total number of rows examined by all iterations of the X-th loop.</dd></p>
<p><a name="sqlitescanstatest"></a>
<dt>SQLITE_SCANSTAT_EST</dt>
<dd>The "double" variable pointed to by the V parameter will be set to the
query planner's estimate for the average number of rows output from each
iteration of the X-th loop. If the query planner's estimates was accurate,
then this value will approximate the quotient NVISIT/NLOOP and the
product of this value for all prior loops with the same SELECTID will
be the NLOOP value for the current loop.</p>
<p><a name="sqlitescanstatname"></a>
<dt>SQLITE_SCANSTAT_NAME</dt>
<dd>The "const char *" variable pointed to by the V parameter will be set
to a zero-terminated UTF-8 string containing the name of the index or table
used for the X-th loop.</p>
<p><a name="sqlitescanstatexplain"></a>
<dt>SQLITE_SCANSTAT_EXPLAIN</dt>
<dd>The "const char *" variable pointed to by the V parameter will be set
to a zero-terminated UTF-8 string containing the <a href="eqp.html">EXPLAIN QUERY PLAN</a>
description for the X-th loop.</p>
<p><a name="sqlitescanstatselectid"></a>
<dt>SQLITE_SCANSTAT_SELECTID</dt>
<dd>The "int" variable pointed to by the V parameter will be set to the
id for the X-th query plan element. The id value is unique within the
statement. The select-id is the same value as is output in the first
column of an <a href="eqp.html">EXPLAIN QUERY PLAN</a> query.</p>
<p><a name="sqlitescanstatparentid"></a>
<dt>SQLITE_SCANSTAT_PARENTID</dt>
<dd>The "int" variable pointed to by the V parameter will be set to the
the id of the parent of the current query element, if applicable, or
to zero if the query element has no parent. This is the same value as
returned in the second column of an <a href="eqp.html">EXPLAIN QUERY PLAN</a> query.</p>
<p><a name="sqlitescanstatncycle"></a>
<dt>SQLITE_SCANSTAT_NCYCLE</dt>
<dd>The sqlite3_int64 output value is set to the number of cycles,
according to the processor time-stamp counter, that elapsed while the
query element was being processed. This value is not available for
all query elements - if it is unavailable the output variable is
set to -1.
</dl>
</p><hr><a name="SQLITE_SHM_EXCLUSIVE"></a>
<h2>Flags for the xShmLock VFS method</h2>
</div>
<blockquote><pre>
#define SQLITE_SHM_UNLOCK 1
#define SQLITE_SHM_LOCK 2
#define SQLITE_SHM_SHARED 4
#define SQLITE_SHM_EXCLUSIVE 8
</pre></blockquote>
<p>
These integer constants define the various locking operations
allowed by the xShmLock method of <a href="#sqlite3_io_methods">sqlite3_io_methods</a>. The
following are the only legal combinations of flags to the
xShmLock method:</p>
<p><ul>
<li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
<li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
<li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
<li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
</ul></p>
<p>When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
was given on the corresponding lock.</p>
<p>The xShmLock method can transition between unlocked and SHARED or
between unlocked and EXCLUSIVE. It cannot transition between SHARED
and EXCLUSIVE.
</p><hr><a name="SQLITE_SOURCE_ID"></a>
<h2>Compile-Time Library Version Numbers</h2>
</div>
<blockquote><pre>
#define SQLITE_VERSION "3.46.0"
#define SQLITE_VERSION_NUMBER 3046000
#define SQLITE_SOURCE_ID "2024-05-23 13:25:27 96c92aba00c8375bc32fafcdf12429c58bd8aabfcadab6683e35bbb9cdebf19e"
</pre></blockquote>
<p>
The <a href="#SQLITE_SOURCE_ID">SQLITE_VERSION</a> C preprocessor macro in the sqlite3.h header
evaluates to a string literal that is the SQLite version in the
format "X.Y.Z" where X is the major version number (always 3 for
SQLite3) and Y is the minor version number and Z is the release number.
The <a href="#SQLITE_SOURCE_ID">SQLITE_VERSION_NUMBER</a> C preprocessor macro resolves to an integer
with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
numbers used in <a href="#SQLITE_SOURCE_ID">SQLITE_VERSION</a>.
The SQLITE_VERSION_NUMBER for any given release of SQLite will also
be larger than the release from which it is derived. Either Y will
be held constant and Z will be incremented or else Y will be incremented
and Z will be reset to zero.</p>
<p>Since <a href="releaselog/3_6_18.html">version 3.6.18</a> (2009-09-11),
SQLite source code has been stored in the
<a href="http://www.fossil-scm.org/">Fossil configuration management
system</a>. The SQLITE_SOURCE_ID macro evaluates to
a string which identifies a particular check-in of SQLite
within its configuration management system. The SQLITE_SOURCE_ID
string contains the date and time of the check-in (UTC) and a SHA1
or SHA3-256 hash of the entire source tree. If the source code has
been edited in any way since it was last checked in, then the last
four hexadecimal digits of the hash may be modified.</p>
<p>See also: <a href="#sqlite3_libversion">sqlite3_libversion()</a>,
<a href="#sqlite3_libversion">sqlite3_libversion_number()</a>, <a href="#sqlite3_libversion">sqlite3_sourceid()</a>,
<a href="lang_corefunc.html#sqlite_version">sqlite_version()</a> and <a href="lang_corefunc.html#sqlite_source_id">sqlite_source_id()</a>.
</p><hr><a name="SQLITE_STATIC"></a>
<h2>Constants Defining Special Destructor Behavior</h2>
</div>
<blockquote><pre>
typedef void (*sqlite3_destructor_type)(void*);
#define SQLITE_STATIC ((sqlite3_destructor_type)0)
#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
</pre></blockquote>
<p>
These are special values for the destructor that is passed in as the
final argument to routines like <a href="#sqlite3_result_blob">sqlite3_result_blob()</a>. If the destructor
argument is SQLITE_STATIC, it means that the content pointer is constant
and will never change. It does not need to be destroyed. The
SQLITE_TRANSIENT value means that the content will likely change in
the near future and that SQLite should make its own private copy of
the content before returning.</p>
<p>The typedef is necessary to work around problems in certain
C++ compilers.
</p><hr><a name="SQLITE_STATUS_MALLOC_COUNT"></a>
<h2>Status Parameters</h2>
</div>
<blockquote><pre>
#define SQLITE_STATUS_MEMORY_USED 0
#define SQLITE_STATUS_PAGECACHE_USED 1
#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */
#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */
#define SQLITE_STATUS_MALLOC_SIZE 5
#define SQLITE_STATUS_PARSER_STACK 6
#define SQLITE_STATUS_PAGECACHE_SIZE 7
#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */
#define SQLITE_STATUS_MALLOC_COUNT 9
</pre></blockquote>
<p>
These integer constants designate various run-time status parameters
that can be returned by <a href="#sqlite3_status">sqlite3_status()</a>.</p>
<p><dl>
<a name="sqlitestatusmemoryused"></a>
<dt>SQLITE_STATUS_MEMORY_USED</dt>
<dd>This parameter is the current amount of memory checked out
using <a href="#sqlite3_free">sqlite3_malloc()</a>, either directly or indirectly. The
figure includes calls made to <a href="#sqlite3_free">sqlite3_malloc()</a> by the application
and internal memory usage by the SQLite library. Auxiliary page-cache
memory controlled by <a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a> is not included in
this parameter. The amount returned is the sum of the allocation
sizes as reported by the xSize method in <a href="#sqlite3_mem_methods">sqlite3_mem_methods</a>.</dd></p>
<p><a name="sqlitestatusmallocsize"></a>
<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
<dd>This parameter records the largest memory allocation request
handed to <a href="#sqlite3_free">sqlite3_malloc()</a> or <a href="#sqlite3_free">sqlite3_realloc()</a> (or their
internal equivalents). Only the value returned in the
*pHighwater parameter to <a href="#sqlite3_status">sqlite3_status()</a> is of interest.
The value written into the *pCurrent parameter is undefined.</dd></p>
<p><a name="sqlitestatusmalloccount"></a>
<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
<dd>This parameter records the number of separate memory allocations
currently checked out.</dd></p>
<p><a name="sqlitestatuspagecacheused"></a>
<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
<dd>This parameter returns the number of pages used out of the
<a href="malloc.html#pagecache">pagecache memory allocator</a> that was configured using
<a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>. The
value returned is in pages, not in bytes.</dd></p>
<p><a name="sqlitestatuspagecacheoverflow"></a>
<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
<dd>This parameter returns the number of bytes of page cache
allocation which could not be satisfied by the <a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>
buffer and where forced to overflow to <a href="#sqlite3_free">sqlite3_malloc()</a>. The
returned value includes allocations that overflowed because they
where too large (they were larger than the "sz" parameter to
<a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>) and allocations that overflowed because
no space was left in the page cache.</dd></p>
<p><a name="sqlitestatuspagecachesize"></a>
<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
<dd>This parameter records the largest memory allocation request
handed to the <a href="malloc.html#pagecache">pagecache memory allocator</a>. Only the value returned in the
*pHighwater parameter to <a href="#sqlite3_status">sqlite3_status()</a> is of interest.
The value written into the *pCurrent parameter is undefined.</dd></p>
<p><a name="sqlitestatusscratchused"></a>
<dt>SQLITE_STATUS_SCRATCH_USED</dt>
<dd>No longer used.</dd></p>
<p><a name="sqlitestatusscratchoverflow"></a>
<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
<dd>No longer used.</dd></p>
<p><a name="sqlitestatusscratchsize"></a>
<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
<dd>No longer used.</dd></p>
<p><a name="sqlitestatusparserstack"></a>
<dt>SQLITE_STATUS_PARSER_STACK</dt>
<dd>The *pHighwater parameter records the deepest parser stack.
The *pCurrent value is undefined. The *pHighwater value is only
meaningful if SQLite is compiled with <a href="compile.html#yytrackmaxstackdepth">YYTRACKMAXSTACKDEPTH</a>.</dd>
</dl></p>
<p>New status parameters may be added from time to time.
</p><hr><a name="SQLITE_SYNC_DATAONLY"></a>
<h2>Synchronization Type Flags</h2>
</div>
<blockquote><pre>
#define SQLITE_SYNC_NORMAL 0x00002
#define SQLITE_SYNC_FULL 0x00003
#define SQLITE_SYNC_DATAONLY 0x00010
</pre></blockquote>
<p>
When SQLite invokes the xSync() method of an
<a href="#sqlite3_io_methods">sqlite3_io_methods</a> object it uses a combination of
these integer values as the second argument.</p>
<p>When the SQLITE_SYNC_DATAONLY flag is used, it means that the
sync operation only needs to flush data to mass storage. Inode
information need not be flushed. If the lower four bits of the flag
equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
If the lower four bits equal SQLITE_SYNC_FULL, that means
to use Mac OS X style fullsync instead of fsync().</p>
<p>Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
with the <a href="pragma.html#pragma_synchronous">PRAGMA synchronous</a>=NORMAL and <a href="pragma.html#pragma_synchronous">PRAGMA synchronous</a>=FULL
settings. The <a href="pragma.html#pragma_synchronous">synchronous pragma</a> determines when calls to the
xSync VFS method occur and applies uniformly across all platforms.
The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
energetic or rigorous or forceful the sync operations are and
only make a difference on Mac OSX for the default SQLite code.
(Third-party VFS implementations might also make the distinction
between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
operating systems natively supported by SQLite, only Mac OSX
cares about the difference.)
</p><hr><a name="SQLITE_TESTCTRL_ALWAYS"></a>
<h2>Testing Interface Operation Codes</h2>
</div>
<blockquote><pre>
#define SQLITE_TESTCTRL_FIRST 5
#define SQLITE_TESTCTRL_PRNG_SAVE 5
#define SQLITE_TESTCTRL_PRNG_RESTORE 6
#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */
#define SQLITE_TESTCTRL_FK_NO_ACTION 7
#define SQLITE_TESTCTRL_BITVEC_TEST 8
#define SQLITE_TESTCTRL_FAULT_INSTALL 9
#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
#define SQLITE_TESTCTRL_PENDING_BYTE 11
#define SQLITE_TESTCTRL_ASSERT 12
#define SQLITE_TESTCTRL_ALWAYS 13
#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */
#define SQLITE_TESTCTRL_JSON_SELFCHECK 14
#define SQLITE_TESTCTRL_OPTIMIZATIONS 15
#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */
#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */
#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17
#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19
#define SQLITE_TESTCTRL_NEVER_CORRUPT 20
#define SQLITE_TESTCTRL_VDBE_COVERAGE 21
#define SQLITE_TESTCTRL_BYTEORDER 22
#define SQLITE_TESTCTRL_ISINIT 23
#define SQLITE_TESTCTRL_SORTER_MMAP 24
#define SQLITE_TESTCTRL_IMPOSTER 25
#define SQLITE_TESTCTRL_PARSER_COVERAGE 26
#define SQLITE_TESTCTRL_RESULT_INTREAL 27
#define SQLITE_TESTCTRL_PRNG_SEED 28
#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29
#define SQLITE_TESTCTRL_SEEK_COUNT 30
#define SQLITE_TESTCTRL_TRACEFLAGS 31
#define SQLITE_TESTCTRL_TUNE 32
#define SQLITE_TESTCTRL_LOGEST 33
#define SQLITE_TESTCTRL_USELONGDOUBLE 34
#define SQLITE_TESTCTRL_LAST 34 /* Largest TESTCTRL */
</pre></blockquote>
<p>
These constants are the valid operation code parameters used
as the first argument to <a href="#sqlite3_test_control">sqlite3_test_control()</a>.</p>
<p>These parameters and their meanings are subject to change
without notice. These values are for testing purposes only.
Applications should not use any of these parameters or the
<a href="#sqlite3_test_control">sqlite3_test_control()</a> interface.
</p><hr><a name="SQLITE_TRACE"></a>
<h2>SQL Trace Event Codes</h2>
</div>
<blockquote><pre>
#define SQLITE_TRACE_STMT 0x01
#define SQLITE_TRACE_PROFILE 0x02
#define SQLITE_TRACE_ROW 0x04
#define SQLITE_TRACE_CLOSE 0x08
</pre></blockquote>
<p>
These constants identify classes of events that can be monitored
using the <a href="#sqlite3_trace_v2">sqlite3_trace_v2()</a> tracing logic. The M argument
to <a href="#sqlite3_trace_v2">sqlite3_trace_v2(D,M,X,P)</a> is an OR-ed combination of one or more of
the following constants. The first argument to the trace callback
is one of the following constants.</p>
<p>New tracing constants may be added in future releases.</p>
<p>A trace callback has four arguments: xCallback(T,C,P,X).
The T argument is one of the integer type codes above.
The C argument is a copy of the context pointer passed in as the
fourth argument to <a href="#sqlite3_trace_v2">sqlite3_trace_v2()</a>.
The P and X arguments are pointers whose meanings depend on T.</p>
<p><dl>
<a name="sqlitetracestmt"></a>
<dt>SQLITE_TRACE_STMT</dt>
<dd>An SQLITE_TRACE_STMT callback is invoked when a prepared statement
first begins running and possibly at other times during the
execution of the prepared statement, such as at the start of each
trigger subprogram. The P argument is a pointer to the
<a href="#sqlite3_stmt">prepared statement</a>. The X argument is a pointer to a string which
is the unexpanded SQL text of the prepared statement or an SQL comment
that indicates the invocation of a trigger. The callback can compute
the same text that would have been returned by the legacy <a href="#sqlite3_profile">sqlite3_trace()</a>
interface by using the X argument when X begins with "--" and invoking
<a href="#sqlite3_expanded_sql">sqlite3_expanded_sql(P)</a> otherwise.</p>
<p><a name="sqlitetraceprofile"></a>
<dt>SQLITE_TRACE_PROFILE</dt>
<dd>An SQLITE_TRACE_PROFILE callback provides approximately the same
information as is provided by the <a href="#sqlite3_profile">sqlite3_profile()</a> callback.
The P argument is a pointer to the <a href="#sqlite3_stmt">prepared statement</a> and the
X argument points to a 64-bit integer which is approximately
the number of nanoseconds that the prepared statement took to run.
The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.</p>
<p><a name="sqlitetracerow"></a>
<dt>SQLITE_TRACE_ROW</dt>
<dd>An SQLITE_TRACE_ROW callback is invoked whenever a prepared
statement generates a single row of result.
The P argument is a pointer to the <a href="#sqlite3_stmt">prepared statement</a> and the
X argument is unused.</p>
<p><a name="sqlitetraceclose"></a>
<dt>SQLITE_TRACE_CLOSE</dt>
<dd>An SQLITE_TRACE_CLOSE callback is invoked when a database
connection closes.
The P argument is a pointer to the <a href="#sqlite3">database connection</a> object
and the X argument is unused.
</dl>
</p><hr><a name="SQLITE_TXN_NONE"></a>
<h2>Allowed return values from sqlite3_txn_state()</h2>
</div>
<blockquote><pre>
#define SQLITE_TXN_NONE 0
#define SQLITE_TXN_READ 1
#define SQLITE_TXN_WRITE 2
</pre></blockquote>
<p>
These constants define the current transaction state of a database file.
The <a href="#sqlite3_txn_state">sqlite3_txn_state(D,S)</a> interface returns one of these
constants in order to describe the transaction state of schema S
in <a href="#sqlite3">database connection</a> D.</p>
<p><dl>
<a name="sqlitetxnnone"></a>
<dt>SQLITE_TXN_NONE</dt>
<dd>The SQLITE_TXN_NONE state means that no transaction is currently
pending.</dd></p>
<p><a name="sqlitetxnread"></a>
<dt>SQLITE_TXN_READ</dt>
<dd>The SQLITE_TXN_READ state means that the database is currently
in a read transaction. Content has been read from the database file
but nothing in the database file has changed. The transaction state
will advanced to SQLITE_TXN_WRITE if any changes occur and there are
no other conflicting concurrent write transactions. The transaction
state will revert to SQLITE_TXN_NONE following a <a href="lang_transaction.html">ROLLBACK</a> or
<a href="lang_transaction.html">COMMIT</a>.</dd></p>
<p><a name="sqlitetxnwrite"></a>
<dt>SQLITE_TXN_WRITE</dt>
<dd>The SQLITE_TXN_WRITE state means that the database is currently
in a write transaction. Content has been written to the database file
but has not yet committed. The transaction state will change to
to SQLITE_TXN_NONE at the next <a href="lang_transaction.html">ROLLBACK</a> or <a href="lang_transaction.html">COMMIT</a>.</dd>
</p><hr><a name="SQLITE_VTAB_CONSTRAINT_SUPPORT"></a>
<h2>Virtual Table Configuration Options</h2>
</div>
<blockquote><pre>
#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
#define SQLITE_VTAB_INNOCUOUS 2
#define SQLITE_VTAB_DIRECTONLY 3
#define SQLITE_VTAB_USES_ALL_SCHEMAS 4
</pre></blockquote>
<p>
These macros define the various options to the
<a href="#sqlite3_vtab_config">sqlite3_vtab_config()</a> interface that <a href="vtab.html">virtual table</a> implementations
can use to customize and optimize their behavior.</p>
<p><dl>
<a name="sqlitevtabconstraintsupport"></a>
<dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
<dd>Calls of the form
<a href="#sqlite3_vtab_config">sqlite3_vtab_config</a>(db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
where X is an integer. If X is zero, then the <a href="vtab.html">virtual table</a> whose
<a href="vtab.html#xcreate">xCreate</a> or <a href="vtab.html#xconnect">xConnect</a> method invoked <a href="#sqlite3_vtab_config">sqlite3_vtab_config()</a> does not
support constraints. In this configuration (which is the default) if
a call to the <a href="vtab.html#xupdate">xUpdate</a> method returns <a href="#SQLITE_ABORT">SQLITE_CONSTRAINT</a>, then the entire
statement is rolled back as if <a href="lang_conflict.html">OR ABORT</a> had been
specified as part of the users SQL statement, regardless of the actual
ON CONFLICT mode specified.</p>
<p>If X is non-zero, then the virtual table implementation guarantees
that if <a href="vtab.html#xupdate">xUpdate</a> returns <a href="#SQLITE_ABORT">SQLITE_CONSTRAINT</a>, it will do so before
any modifications to internal or persistent data structures have been made.
If the <a href="lang_conflict.html">ON CONFLICT</a> mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
is able to roll back a statement or database transaction, and abandon
or continue processing the current SQL statement as appropriate.
If the ON CONFLICT mode is REPLACE and the <a href="vtab.html#xupdate">xUpdate</a> method returns
<a href="#SQLITE_ABORT">SQLITE_CONSTRAINT</a>, SQLite handles this as if the ON CONFLICT mode
had been ABORT.</p>
<p>Virtual table implementations that are required to handle OR REPLACE
must do so within the <a href="vtab.html#xupdate">xUpdate</a> method. If a call to the
<a href="#sqlite3_vtab_on_conflict">sqlite3_vtab_on_conflict()</a> function indicates that the current ON
CONFLICT policy is REPLACE, the virtual table implementation should
silently replace the appropriate rows within the xUpdate callback and
return SQLITE_OK. Or, if this is not possible, it may return
SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
constraint handling.
</dd></p>
<p><a name="sqlitevtabdirectonly"></a>
<dt>SQLITE_VTAB_DIRECTONLY</dt>
<dd>Calls of the form
<a href="#sqlite3_vtab_config">sqlite3_vtab_config</a>(db,SQLITE_VTAB_DIRECTONLY) from within the
the <a href="vtab.html#xconnect">xConnect</a> or <a href="vtab.html#xcreate">xCreate</a> methods of a <a href="vtab.html">virtual table</a> implementation
prohibits that virtual table from being used from within triggers and
views.
</dd></p>
<p><a name="sqlitevtabinnocuous"></a>
<dt>SQLITE_VTAB_INNOCUOUS</dt>
<dd>Calls of the form
<a href="#sqlite3_vtab_config">sqlite3_vtab_config</a>(db,SQLITE_VTAB_INNOCUOUS) from within the
the <a href="vtab.html#xconnect">xConnect</a> or <a href="vtab.html#xcreate">xCreate</a> methods of a <a href="vtab.html">virtual table</a> implementation
identify that virtual table as being safe to use from within triggers
and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
virtual table can do no serious harm even if it is controlled by a
malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
flag unless absolutely necessary.
</dd></p>
<p><a name="sqlitevtabusesallschemas"></a>
<dt>SQLITE_VTAB_USES_ALL_SCHEMAS</dt>
<dd>Calls of the form
<a href="#sqlite3_vtab_config">sqlite3_vtab_config</a>(db,SQLITE_VTAB_USES_ALL_SCHEMA) from within the
the <a href="vtab.html#xconnect">xConnect</a> or <a href="vtab.html#xcreate">xCreate</a> methods of a <a href="vtab.html">virtual table</a> implementation
instruct the query planner to begin at least a read transaction on
all schemas ("main", "temp", and any ATTACH-ed databases) whenever the
virtual table is used.
</dd>
</dl>
</p><hr><a name="SQLITE_WIN32_DATA_DIRECTORY_TYPE"></a>
<h2>Win32 Directory Types</h2>
</div>
<blockquote><pre>
#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1
#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2
</pre></blockquote>
<p>
These macros are only available on Windows. They define the allowed values
for the type argument to the <a href="#sqlite3_win32_set_directory">sqlite3_win32_set_directory</a> interface.
</p><hr><a name="SQLITE_LIMIT_ATTACHED"></a>
<h2>Run-Time Limit Categories</h2>
</div>
<blockquote><pre>
#define SQLITE_LIMIT_LENGTH 0
#define SQLITE_LIMIT_SQL_LENGTH 1
#define SQLITE_LIMIT_COLUMN 2
#define SQLITE_LIMIT_EXPR_DEPTH 3
#define SQLITE_LIMIT_COMPOUND_SELECT 4
#define SQLITE_LIMIT_VDBE_OP 5
#define SQLITE_LIMIT_FUNCTION_ARG 6
#define SQLITE_LIMIT_ATTACHED 7
#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
#define SQLITE_LIMIT_VARIABLE_NUMBER 9
#define SQLITE_LIMIT_TRIGGER_DEPTH 10
#define SQLITE_LIMIT_WORKER_THREADS 11
</pre></blockquote>
<p>
These constants define various performance limits
that can be lowered at run-time using <a href="#sqlite3_limit">sqlite3_limit()</a>.
The synopsis of the meanings of the various limits is shown below.
Additional information is available at <a href="limits.html">Limits in SQLite</a>.</p>
<p><dl>
<a name="sqlitelimitlength"></a>
<dt>SQLITE_LIMIT_LENGTH</dt>
<dd>The maximum size of any string or BLOB or table row, in bytes.<dd></p>
<p><a name="sqlitelimitsqllength"></a>
<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
<dd>The maximum length of an SQL statement, in bytes.</dd></p>
<p><a name="sqlitelimitcolumn"></a>
<dt>SQLITE_LIMIT_COLUMN</dt>
<dd>The maximum number of columns in a table definition or in the
result set of a <a href="lang_select.html">SELECT</a> or the maximum number of columns in an index
or in an ORDER BY or GROUP BY clause.</dd></p>
<p><a name="sqlitelimitexprdepth"></a>
<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
<dd>The maximum depth of the parse tree on any expression.</dd></p>
<p><a name="sqlitelimitcompoundselect"></a>
<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
<dd>The maximum number of terms in a compound SELECT statement.</dd></p>
<p><a name="sqlitelimitvdbeop"></a>
<dt>SQLITE_LIMIT_VDBE_OP</dt>
<dd>The maximum number of instructions in a virtual machine program
used to implement an SQL statement. If <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> or
the equivalent tries to allocate space for more than this many opcodes
in a single prepared statement, an SQLITE_NOMEM error is returned.</dd></p>
<p><a name="sqlitelimitfunctionarg"></a>
<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
<dd>The maximum number of arguments on a function.</dd></p>
<p><a name="sqlitelimitattached"></a>
<dt>SQLITE_LIMIT_ATTACHED</dt>
<dd>The maximum number of <a href="lang_attach.html">attached databases</a>.</dd></p>
<p><a name="sqlitelimitlikepatternlength"></a>
<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
<dd>The maximum length of the pattern argument to the <a href="lang_expr.html#like">LIKE</a> or
<a href="lang_expr.html#glob">GLOB</a> operators.</dd></p>
<p><a name="sqlitelimitvariablenumber"></a>
<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
<dd>The maximum index number of any <a href="lang_expr.html#varparam">parameter</a> in an SQL statement.</p>
<p><a name="sqlitelimittriggerdepth"></a>
<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
<dd>The maximum depth of recursion for triggers.</dd></p>
<p><a name="sqlitelimitworkerthreads"></a>
<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
<dd>The maximum number of auxiliary worker threads that a single
<a href="#sqlite3_stmt">prepared statement</a> may start.</dd>
</dl>
</p><hr><a name="SQLITE_DBSTATUS options"></a>
<h2>Status Parameters for database connections</h2>
</div>
<blockquote><pre>
#define SQLITE_DBSTATUS_LOOKASIDE_USED 0
#define SQLITE_DBSTATUS_CACHE_USED 1
#define SQLITE_DBSTATUS_SCHEMA_USED 2
#define SQLITE_DBSTATUS_STMT_USED 3
#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
#define SQLITE_DBSTATUS_CACHE_HIT 7
#define SQLITE_DBSTATUS_CACHE_MISS 8
#define SQLITE_DBSTATUS_CACHE_WRITE 9
#define SQLITE_DBSTATUS_DEFERRED_FKS 10
#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11
#define SQLITE_DBSTATUS_CACHE_SPILL 12
#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */
</pre></blockquote>
<p>
These constants are the available integer "verbs" that can be passed as
the second argument to the <a href="#sqlite3_db_status">sqlite3_db_status()</a> interface.</p>
<p>New verbs may be added in future releases of SQLite. Existing verbs
might be discontinued. Applications should check the return code from
<a href="#sqlite3_db_status">sqlite3_db_status()</a> to make sure that the call worked.
The <a href="#sqlite3_db_status">sqlite3_db_status()</a> interface will return a non-zero error code
if a discontinued or unsupported verb is invoked.</p>
<p><dl>
<a name="sqlitedbstatuslookasideused"></a>
<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
<dd>This parameter returns the number of lookaside memory slots currently
checked out.</dd></p>
<p><a name="sqlitedbstatuslookasidehit"></a>
<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
<dd>This parameter returns the number of malloc attempts that were
satisfied using lookaside memory. Only the high-water value is meaningful;
the current value is always zero.</p>
<p><a name="sqlitedbstatuslookasidemisssize"></a>
<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
<dd>This parameter returns the number malloc attempts that might have
been satisfied using lookaside memory but failed due to the amount of
memory requested being larger than the lookaside slot size.
Only the high-water value is meaningful;
the current value is always zero.</p>
<p><a name="sqlitedbstatuslookasidemissfull"></a>
<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
<dd>This parameter returns the number malloc attempts that might have
been satisfied using lookaside memory but failed due to all lookaside
memory already being in use.
Only the high-water value is meaningful;
the current value is always zero.</p>
<p><a name="sqlitedbstatuscacheused"></a>
<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
<dd>This parameter returns the approximate number of bytes of heap
memory used by all pager caches associated with the database connection.
The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.</p>
<p><a name="sqlitedbstatuscacheusedshared"></a>
<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
<dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
pager cache is shared between two or more connections the bytes of heap
memory used by that pager cache is divided evenly between the attached
connections. In other words, if none of the pager caches associated
with the database connection are shared, this request returns the same
value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
shared, the value returned by this call will be smaller than that returned
by DBSTATUS_CACHE_USED. The highwater mark associated with
SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.</p>
<p><a name="sqlitedbstatusschemaused"></a>
<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
<dd>This parameter returns the approximate number of bytes of heap
memory used to store the schema for all databases associated
with the connection - main, temp, and any <a href="lang_attach.html">ATTACH</a>-ed databases.
The full amount of memory used by the schemas is reported, even if the
schema memory is shared with other database connections due to
<a href="sharedcache.html">shared cache mode</a> being enabled.
The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.</p>
<p><a name="sqlitedbstatusstmtused"></a>
<dt>SQLITE_DBSTATUS_STMT_USED</dt>
<dd>This parameter returns the approximate number of bytes of heap
and lookaside memory used by all prepared statements associated with
the database connection.
The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
</dd></p>
<p><a name="sqlitedbstatuscachehit"></a>
<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
<dd>This parameter returns the number of pager cache hits that have
occurred. The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
is always 0.
</dd></p>
<p><a name="sqlitedbstatuscachemiss"></a>
<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
<dd>This parameter returns the number of pager cache misses that have
occurred. The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
is always 0.
</dd></p>
<p><a name="sqlitedbstatuscachewrite"></a>
<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
<dd>This parameter returns the number of dirty cache entries that have
been written to disk. Specifically, the number of pages written to the
wal file in wal mode databases, or the number of pages written to the
database file in rollback mode databases. Any pages written as part of
transaction rollback or database recovery operations are not included.
If an IO or other error occurs while writing a page to disk, the effect
on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined. The
highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
</dd></p>
<p><a name="sqlitedbstatuscachespill"></a>
<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
<dd>This parameter returns the number of dirty cache entries that have
been written to disk in the middle of a transaction due to the page
cache overflowing. Transactions are more efficient if they are written
to disk all at once. When pages spill mid-transaction, that introduces
additional overhead. This parameter can be used help identify
inefficiencies that can be resolved by increasing the cache size.
</dd></p>
<p><a name="sqlitedbstatusdeferredfks"></a>
<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
<dd>This parameter returns zero for the current value if and only if
all foreign key constraints (deferred or immediate) have been
resolved. The highwater mark is always 0.
</dd>
</dl>
</p><hr><a name="SQLITE_STMTSTATUS counter"></a>
<h2>Status Parameters for prepared statements</h2>
</div>
<blockquote><pre>
#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
#define SQLITE_STMTSTATUS_SORT 2
#define SQLITE_STMTSTATUS_AUTOINDEX 3
#define SQLITE_STMTSTATUS_VM_STEP 4
#define SQLITE_STMTSTATUS_REPREPARE 5
#define SQLITE_STMTSTATUS_RUN 6
#define SQLITE_STMTSTATUS_FILTER_MISS 7
#define SQLITE_STMTSTATUS_FILTER_HIT 8
#define SQLITE_STMTSTATUS_MEMUSED 99
</pre></blockquote>
<p>
These preprocessor macros define integer codes that name counter
values associated with the <a href="#sqlite3_stmt_status">sqlite3_stmt_status()</a> interface.
The meanings of the various counters are as follows:</p>
<p><dl>
<a name="sqlitestmtstatusfullscanstep"></a>
<dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
<dd>This is the number of times that SQLite has stepped forward in
a table as part of a full table scan. Large numbers for this counter
may indicate opportunities for performance improvement through
careful use of indices.</dd></p>
<p><a name="sqlitestmtstatussort"></a>
<dt>SQLITE_STMTSTATUS_SORT</dt>
<dd>This is the number of sort operations that have occurred.
A non-zero value in this counter may indicate an opportunity to
improvement performance through careful use of indices.</dd></p>
<p><a name="sqlitestmtstatusautoindex"></a>
<dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
<dd>This is the number of rows inserted into transient indices that
were created automatically in order to help joins run faster.
A non-zero value in this counter may indicate an opportunity to
improvement performance by adding permanent indices that do not
need to be reinitialized each time the statement is run.</dd></p>
<p><a name="sqlitestmtstatusvmstep"></a>
<dt>SQLITE_STMTSTATUS_VM_STEP</dt>
<dd>This is the number of virtual machine operations executed
by the prepared statement if that number is less than or equal
to 2147483647. The number of virtual machine operations can be
used as a proxy for the total work done by the prepared statement.
If the number of virtual machine operations exceeds 2147483647
then the value returned by this statement status code is undefined.</p>
<p><a name="sqlitestmtstatusreprepare"></a>
<dt>SQLITE_STMTSTATUS_REPREPARE</dt>
<dd>This is the number of times that the prepare statement has been
automatically regenerated due to schema changes or changes to
<a href="lang_expr.html#varparam">bound parameters</a> that might affect the query plan.</p>
<p><a name="sqlitestmtstatusrun"></a>
<dt>SQLITE_STMTSTATUS_RUN</dt>
<dd>This is the number of times that the prepared statement has
been run. A single "run" for the purposes of this counter is one
or more calls to <a href="#sqlite3_step">sqlite3_step()</a> followed by a call to <a href="#sqlite3_reset">sqlite3_reset()</a>.
The counter is incremented on the first <a href="#sqlite3_step">sqlite3_step()</a> call of each
cycle.</p>
<p><a name="sqlitestmtstatusfiltermiss"></a>
<a name="sqlitestmtstatusfilterhit"></a>
<dt>SQLITE_STMTSTATUS_FILTER_HIT<br>
SQLITE_STMTSTATUS_FILTER_MISS</dt>
<dd>SQLITE_STMTSTATUS_FILTER_HIT is the number of times that a join
step was bypassed because a Bloom filter returned not-found. The
corresponding SQLITE_STMTSTATUS_FILTER_MISS value is the number of
times that the Bloom filter returned a find, and thus the join step
had to be processed as normal.</p>
<p><a name="sqlitestmtstatusmemused"></a>
<dt>SQLITE_STMTSTATUS_MEMUSED</dt>
<dd>This is the approximate number of bytes of heap memory
used to store the prepared statement. This value is not actually
a counter, and so the resetFlg parameter to sqlite3_stmt_status()
is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
</dd>
</dl>
</p><hr><a name="sqlite3_snapshot"></a>
<h2>Database Snapshot</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_snapshot {
unsigned char hidden[48];
} sqlite3_snapshot;
</pre></blockquote>
<p>
An instance of the snapshot object records the state of a <a href="wal.html">WAL mode</a>
database for some specific point in history.</p>
<p>In <a href="wal.html">WAL mode</a>, multiple <a href="#sqlite3">database connections</a> that are open on the
same database file can each be reading a different historical version
of the database file. When a <a href="#sqlite3">database connection</a> begins a read
transaction, that connection sees an unchanging copy of the database
as it existed for the point in time when the transaction first started.
Subsequent changes to the database from other connections are not seen
by the reader until a new read transaction is started.</p>
<p>The sqlite3_snapshot object records state information about an historical
version of the database file so that it is possible to later open a new read
transaction that sees that historical version of the database rather than
the most recent version.
</p><p>1 Constructor using this object: <a href="#sqlite3_snapshot_get">sqlite3_snapshot_get()</a></p>
<p>1 Destructor using this object: <a href="#sqlite3_snapshot_free">sqlite3_snapshot_free()</a></p>
<p>3 Methods using this object:
<a href="#sqlite3_snapshot_cmp">sqlite3_snapshot_cmp()</a>,
<a href="#sqlite3_snapshot_open">sqlite3_snapshot_open()</a>,
<a href="#sqlite3_snapshot_recover">sqlite3_snapshot_recover()</a></p>
<hr><a name="sqlite3_int64"></a>
<h2>64-Bit Integer Types</h2>
</div>
<blockquote><pre>
#ifdef SQLITE_INT64_TYPE
typedef SQLITE_INT64_TYPE sqlite_int64;
# ifdef SQLITE_UINT64_TYPE
typedef SQLITE_UINT64_TYPE sqlite_uint64;
# else
typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
# endif
#elif defined(_MSC_VER) || defined(__BORLANDC__)
typedef __int64 sqlite_int64;
typedef unsigned __int64 sqlite_uint64;
#else
typedef long long int sqlite_int64;
typedef unsigned long long int sqlite_uint64;
#endif
typedef sqlite_int64 sqlite3_int64;
typedef sqlite_uint64 sqlite3_uint64;
</pre></blockquote>
<p>
Because there is no cross-platform way to specify 64-bit integer types
SQLite includes typedefs for 64-bit signed and unsigned integers.</p>
<p>The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
The sqlite_int64 and sqlite_uint64 types are supported for backwards
compatibility only.</p>
<p>The sqlite3_int64 and sqlite_int64 types can store integer values
between -9223372036854775808 and +9223372036854775807 inclusive. The
sqlite3_uint64 and sqlite_uint64 types can store integer values
between 0 and +18446744073709551615 inclusive.
</p><hr><a name="sqlite3_module"></a>
<h2>Virtual Table Object</h2>
</div>
<blockquote><pre>
struct sqlite3_module {
int iVersion;
int (*xCreate)(sqlite3*, void *pAux,
int argc, const char *const*argv,
sqlite3_vtab **ppVTab, char**);
int (*xConnect)(sqlite3*, void *pAux,
int argc, const char *const*argv,
sqlite3_vtab **ppVTab, char**);
int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
int (*xDisconnect)(sqlite3_vtab *pVTab);
int (*xDestroy)(sqlite3_vtab *pVTab);
int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
int (*xClose)(sqlite3_vtab_cursor*);
int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
int argc, sqlite3_value **argv);
int (*xNext)(sqlite3_vtab_cursor*);
int (*xEof)(sqlite3_vtab_cursor*);
int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
int (*xBegin)(sqlite3_vtab *pVTab);
int (*xSync)(sqlite3_vtab *pVTab);
int (*xCommit)(sqlite3_vtab *pVTab);
int (*xRollback)(sqlite3_vtab *pVTab);
int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
void **ppArg);
int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
/* The methods above are in version 1 of the sqlite_module object. Those
** below are for version 2 and greater. */
int (*xSavepoint)(sqlite3_vtab *pVTab, int);
int (*xRelease)(sqlite3_vtab *pVTab, int);
int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
/* The methods above are in versions 1 and 2 of the sqlite_module object.
** Those below are for version 3 and greater. */
int (*xShadowName)(const char*);
/* The methods above are in versions 1 through 3 of the sqlite_module object.
** Those below are for version 4 and greater. */
int (*xIntegrity)(sqlite3_vtab *pVTab, const char *zSchema,
const char *zTabName, int mFlags, char **pzErr);
};
</pre></blockquote>
<p>
This structure, sometimes called a "virtual table module",
defines the implementation of a <a href="vtab.html">virtual table</a>.
This structure consists mostly of methods for the module.</p>
<p>A virtual table module is created by filling in a persistent
instance of this structure and passing a pointer to that instance
to <a href="#sqlite3_create_module">sqlite3_create_module()</a> or <a href="#sqlite3_create_module">sqlite3_create_module_v2()</a>.
The registration remains valid until it is replaced by a different
module or until the <a href="#sqlite3">database connection</a> closes. The content
of this structure must not change while it is registered with
any database connection.
</p><hr><a name="sqlite3_vtab_cursor"></a>
<h2>Virtual Table Cursor Object</h2>
</div>
<blockquote><pre>
struct sqlite3_vtab_cursor {
sqlite3_vtab *pVtab; /* Virtual table of this cursor */
/* Virtual table implementations will typically add additional fields */
};
</pre></blockquote>
<p>
Every <a href="#sqlite3_module">virtual table module</a> implementation uses a subclass of the
following structure to describe cursors that point into the
<a href="vtab.html">virtual table</a> and are used
to loop through the virtual table. Cursors are created using the
<a href="vtab.html#xopen">xOpen</a> method of the module and are destroyed
by the <a href="vtab.html#xclose">xClose</a> method. Cursors are used
by the <a href="vtab.html#xfilter">xFilter</a>, <a href="vtab.html#xnext">xNext</a>, <a href="vtab.html#xeof">xEof</a>, <a href="vtab.html#xcolumn">xColumn</a>, and <a href="vtab.html#xrowid">xRowid</a> methods
of the module. Each module implementation will define
the content of a cursor structure to suit its own needs.</p>
<p>This superclass exists in order to define fields of the cursor that
are common to all implementations.
</p><hr><a name="sqlite3_blob"></a>
<h2>A Handle To An Open BLOB</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_blob sqlite3_blob;
</pre></blockquote>
<p>
An instance of this object represents an open BLOB on which
<a href="#sqlite3_blob_open">incremental BLOB I/O</a> can be performed.
Objects of this type are created by <a href="#sqlite3_blob_open">sqlite3_blob_open()</a>
and destroyed by <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>.
The <a href="#sqlite3_blob_read">sqlite3_blob_read()</a> and <a href="#sqlite3_blob_write">sqlite3_blob_write()</a> interfaces
can be used to read or write small subsections of the BLOB.
The <a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a> interface returns the size of the BLOB in bytes.
</p><p>1 Constructor using this object: <a href="#sqlite3_blob_open">sqlite3_blob_open()</a></p>
<p>1 Destructor using this object: <a href="#sqlite3_blob_close">sqlite3_blob_close()</a></p>
<p>4 Methods using this object:
<a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a>,
<a href="#sqlite3_blob_read">sqlite3_blob_read()</a>,
<a href="#sqlite3_blob_reopen">sqlite3_blob_reopen()</a>,
<a href="#sqlite3_blob_write">sqlite3_blob_write()</a></p>
<hr><a name="sqlite3"></a>
<h2>Database Connection Handle</h2>
</div>
<blockquote><pre>
typedef struct sqlite3 sqlite3;
</pre></blockquote>
<p>
Each open SQLite database is represented by a pointer to an instance of
the opaque structure named "sqlite3". It is useful to think of an sqlite3
pointer as an object. The <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open16()</a>, and
<a href="#sqlite3_open">sqlite3_open_v2()</a> interfaces are its constructors, and <a href="#sqlite3_close">sqlite3_close()</a>
and <a href="#sqlite3_close">sqlite3_close_v2()</a> are its destructors. There are many other
interfaces (such as
<a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>, <a href="#sqlite3_create_function">sqlite3_create_function()</a>, and
<a href="#sqlite3_busy_timeout">sqlite3_busy_timeout()</a> to name but three) that are methods on an
sqlite3 object.
</p><p>3 Constructors using this object:
<a href="#sqlite3_open">sqlite3_open()</a>,
<a href="#sqlite3_open">sqlite3_open16()</a>,
<a href="#sqlite3_open">sqlite3_open_v2()</a></p>
<p>2 Destructors using this object:
<a href="#sqlite3_close">sqlite3_close()</a>,
<a href="#sqlite3_close">sqlite3_close_v2()</a></p>
<p>77 Methods using this object:
<div class='columns' style='columns: 17em auto;'>
<ul style='padding-top:0;'>
<li><a href='#sqlite3_autovacuum_pages'>sqlite3_autovacuum_pages</a></li>
<li><a href='#sqlite3_blob_open'>sqlite3_blob_open</a></li>
<li><a href='#sqlite3_busy_handler'>sqlite3_busy_handler</a></li>
<li><a href='#sqlite3_busy_timeout'>sqlite3_busy_timeout</a></li>
<li><a href='#sqlite3_changes'>sqlite3_changes</a></li>
<li><a href='#sqlite3_changes'>sqlite3_changes64</a></li>
<li><a href='#sqlite3_collation_needed'>sqlite3_collation_needed</a></li>
<li><a href='#sqlite3_collation_needed'>sqlite3_collation_needed16</a></li>
<li><a href='#sqlite3_commit_hook'>sqlite3_commit_hook</a></li>
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation</a></li>
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation16</a></li>
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation_v2</a></li>
<li><a href='#sqlite3_create_function'>sqlite3_create_function</a></li>
<li><a href='#sqlite3_create_function'>sqlite3_create_function16</a></li>
<li><a href='#sqlite3_create_function'>sqlite3_create_function_v2</a></li>
<li><a href='#sqlite3_create_module'>sqlite3_create_module</a></li>
<li><a href='#sqlite3_create_module'>sqlite3_create_module_v2</a></li>
<li><a href='#sqlite3_create_function'>sqlite3_create_window_function</a></li>
<li><a href='#sqlite3_db_cacheflush'>sqlite3_db_cacheflush</a></li>
<li><a href='#sqlite3_db_config'>sqlite3_db_config</a></li>
<li><a href='#sqlite3_db_filename'>sqlite3_db_filename</a></li>
<li><a href='#sqlite3_db_mutex'>sqlite3_db_mutex</a></li>
<li><a href='#sqlite3_db_name'>sqlite3_db_name</a></li>
<li><a href='#sqlite3_db_readonly'>sqlite3_db_readonly</a></li>
<li><a href='#sqlite3_db_release_memory'>sqlite3_db_release_memory</a></li>
<li><a href='#sqlite3_db_status'>sqlite3_db_status</a></li>
<li><a href='#sqlite3_drop_modules'>sqlite3_drop_modules</a></li>
<li><a href='#sqlite3_enable_load_extension'>sqlite3_enable_load_extension</a></li>
<li><a href='#sqlite3_errcode'>sqlite3_errcode</a></li>
<li><a href='#sqlite3_errcode'>sqlite3_errmsg</a></li>
<li><a href='#sqlite3_errcode'>sqlite3_errmsg16</a></li>
<li><a href='#sqlite3_errcode'>sqlite3_error_offset</a></li>
<li><a href='#sqlite3_errcode'>sqlite3_errstr</a></li>
<li><a href='#sqlite3_exec'>sqlite3_exec</a></li>
<li><a href='#sqlite3_errcode'>sqlite3_extended_errcode</a></li>
<li><a href='#sqlite3_extended_result_codes'>sqlite3_extended_result_codes</a></li>
<li><a href='#sqlite3_file_control'>sqlite3_file_control</a></li>
<li><a href='#sqlite3_free_table'>sqlite3_free_table</a></li>
<li><a href='#sqlite3_get_autocommit'>sqlite3_get_autocommit</a></li>
<li><a href='#sqlite3_get_clientdata'>sqlite3_get_clientdata</a></li>
<li><a href='#sqlite3_free_table'>sqlite3_get_table</a></li>
<li><a href='#sqlite3_interrupt'>sqlite3_interrupt</a></li>
<li><a href='#sqlite3_interrupt'>sqlite3_is_interrupted</a></li>
<li><a href='#sqlite3_last_insert_rowid'>sqlite3_last_insert_rowid</a></li>
<li><a href='#sqlite3_limit'>sqlite3_limit</a></li>
<li><a href='#sqlite3_load_extension'>sqlite3_load_extension</a></li>
<li><a href='#sqlite3_next_stmt'>sqlite3_next_stmt</a></li>
<li><a href='#sqlite3_overload_function'>sqlite3_overload_function</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare16</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v2</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v3</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v2</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v3</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_blobwrite</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_count</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_depth</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_hook</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_new</a></li>
<li><a href='#sqlite3_preupdate_blobwrite'>sqlite3_preupdate_old</a></li>
<li><a href='#sqlite3_progress_handler'>sqlite3_progress_handler</a></li>
<li><a href='#sqlite3_commit_hook'>sqlite3_rollback_hook</a></li>
<li><a href='#sqlite3_set_authorizer'>sqlite3_set_authorizer</a></li>
<li><a href='#sqlite3_get_clientdata'>sqlite3_set_clientdata</a></li>
<li><a href='#sqlite3_set_last_insert_rowid'>sqlite3_set_last_insert_rowid</a></li>
<li><a href='#sqlite3_system_errno'>sqlite3_system_errno</a></li>
<li><a href='#sqlite3_table_column_metadata'>sqlite3_table_column_metadata</a></li>
<li><a href='#sqlite3_total_changes'>sqlite3_total_changes</a></li>
<li><a href='#sqlite3_total_changes'>sqlite3_total_changes64</a></li>
<li><a href='#sqlite3_trace_v2'>sqlite3_trace_v2</a></li>
<li><a href='#sqlite3_txn_state'>sqlite3_txn_state</a></li>
<li><a href='#sqlite3_unlock_notify'>sqlite3_unlock_notify</a></li>
<li><a href='#sqlite3_update_hook'>sqlite3_update_hook</a></li>
<li><a href='#sqlite3_wal_autocheckpoint'>sqlite3_wal_autocheckpoint</a></li>
<li><a href='#sqlite3_wal_checkpoint'>sqlite3_wal_checkpoint</a></li>
<li><a href='#sqlite3_wal_checkpoint_v2'>sqlite3_wal_checkpoint_v2</a></li>
<li><a href='#sqlite3_wal_hook'>sqlite3_wal_hook</a></li>
</ul>
</div>
</p>
<hr><a name="sqlite3_str"></a>
<h2>Dynamic String Object</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_str sqlite3_str;
</pre></blockquote>
<p>
An instance of the sqlite3_str object contains a dynamically-sized
string under construction.</p>
<p>The lifecycle of an sqlite3_str object is as follows:
<ol>
<li> The sqlite3_str object is created using <a href="#sqlite3_str_new">sqlite3_str_new()</a>.
<li> Text is appended to the sqlite3_str object using various
methods, such as <a href="#sqlite3_str_append">sqlite3_str_appendf()</a>.
<li> The sqlite3_str object is destroyed and the string it created
is returned using the <a href="#sqlite3_str_finish">sqlite3_str_finish()</a> interface.
</ol>
</p><p>1 Constructor using this object: <a href="#sqlite3_str_new">sqlite3_str_new()</a></p>
<p>1 Destructor using this object: <a href="#sqlite3_str_finish">sqlite3_str_finish()</a></p>
<p>9 Methods using this object:
<div class='columns' style='columns: 17em auto;'>
<ul style='padding-top:0;'>
<li><a href='#sqlite3_str_append'>sqlite3_str_append</a></li>
<li><a href='#sqlite3_str_append'>sqlite3_str_appendall</a></li>
<li><a href='#sqlite3_str_append'>sqlite3_str_appendchar</a></li>
<li><a href='#sqlite3_str_append'>sqlite3_str_appendf</a></li>
<li><a href='#sqlite3_str_errcode'>sqlite3_str_errcode</a></li>
<li><a href='#sqlite3_str_errcode'>sqlite3_str_length</a></li>
<li><a href='#sqlite3_str_append'>sqlite3_str_reset</a></li>
<li><a href='#sqlite3_str_errcode'>sqlite3_str_value</a></li>
<li><a href='#sqlite3_str_append'>sqlite3_str_vappendf</a></li>
</ul>
</div>
</p>
<hr><a name="sqlite3_pcache_methods2"></a>
<h2>Application Defined Page Cache.</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
struct sqlite3_pcache_methods2 {
int iVersion;
void *pArg;
int (*xInit)(void*);
void (*xShutdown)(void*);
sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
void (*xCachesize)(sqlite3_pcache*, int nCachesize);
int (*xPagecount)(sqlite3_pcache*);
sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
unsigned oldKey, unsigned newKey);
void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
void (*xDestroy)(sqlite3_pcache*);
void (*xShrink)(sqlite3_pcache*);
};
</pre></blockquote>
<p>
The <a href="#sqlite3_config">sqlite3_config</a>(<a href="#sqliteconfigpcache2">SQLITE_CONFIG_PCACHE2</a>, ...) interface can
register an alternative page cache implementation by passing in an
instance of the sqlite3_pcache_methods2 structure.
In many applications, most of the heap memory allocated by
SQLite is used for the page cache.
By implementing a
custom page cache using this API, an application can better control
the amount of memory consumed by SQLite, the way in which
that memory is allocated and released, and the policies used to
determine exactly which parts of a database file are cached and for
how long.</p>
<p>The alternative page cache mechanism is an
extreme measure that is only needed by the most demanding applications.
The built-in page cache is recommended for most uses.</p>
<p>The contents of the sqlite3_pcache_methods2 structure are copied to an
internal buffer by SQLite within the call to <a href="#sqlite3_config">sqlite3_config</a>. Hence
the application may discard the parameter after the call to
<a href="#sqlite3_config">sqlite3_config()</a> returns.</p>
<p><a name="thexinitpagecachemethod"></a>
The xInit() method is called once for each effective
call to <a href="#sqlite3_initialize">sqlite3_initialize()</a>
(usually only once during the lifetime of the process). The xInit()
method is passed a copy of the sqlite3_pcache_methods2.pArg value.
The intent of the xInit() method is to set up global data structures
required by the custom page cache implementation.
If the xInit() method is NULL, then the
built-in default page cache is used instead of the application defined
page cache.</p>
<p><a name="thexshutdownpagecachemethod"></a>
The xShutdown() method is called by <a href="#sqlite3_initialize">sqlite3_shutdown()</a>.
It can be used to clean up
any outstanding resources before process shutdown, if required.
The xShutdown() method may be NULL.</p>
<p>SQLite automatically serializes calls to the xInit method,
so the xInit method need not be threadsafe. The
xShutdown method is only called from <a href="#sqlite3_initialize">sqlite3_shutdown()</a> so it does
not need to be threadsafe either. All other methods must be threadsafe
in multithreaded applications.</p>
<p>SQLite will never invoke xInit() more than once without an intervening
call to xShutdown().</p>
<p><a name="thexcreatepagecachemethods"></a>
SQLite invokes the xCreate() method to construct a new cache instance.
SQLite will typically create one cache instance for each open database file,
though this is not guaranteed. The
first parameter, szPage, is the size in bytes of the pages that must
be allocated by the cache. szPage will always a power of two. The
second parameter szExtra is a number of bytes of extra storage
associated with each page cache entry. The szExtra parameter will
a number less than 250. SQLite will use the
extra szExtra bytes on each page to store metadata about the underlying
database page on disk. The value passed into szExtra depends
on the SQLite version, the target platform, and how SQLite was compiled.
The third argument to xCreate(), bPurgeable, is true if the cache being
created will be used to cache database pages of a file stored on disk, or
false if it is used for an in-memory database. The cache implementation
does not have to do anything special based with the value of bPurgeable;
it is purely advisory. On a cache where bPurgeable is false, SQLite will
never invoke xUnpin() except to deliberately delete a page.
In other words, calls to xUnpin() on a cache with bPurgeable set to
false will always have the "discard" flag set to true.
Hence, a cache created with bPurgeable false will
never contain any unpinned pages.</p>
<p><a name="thexcachesizepagecachemethod"></a>
The xCachesize() method may be called at any time by SQLite to set the
suggested maximum cache-size (number of pages stored by) the cache
instance passed as the first argument. This is the value configured using
the SQLite "<a href="pragma.html#pragma_cache_size">PRAGMA cache_size</a>" command. As with the bPurgeable
parameter, the implementation is not required to do anything with this
value; it is advisory only.</p>
<p><a name="thexpagecountpagecachemethods"></a>
The xPagecount() method must return the number of pages currently
stored in the cache, both pinned and unpinned.</p>
<p><a name="thexfetchpagecachemethods"></a>
The xFetch() method locates a page in the cache and returns a pointer to
an sqlite3_pcache_page object associated with that page, or a NULL pointer.
The pBuf element of the returned sqlite3_pcache_page object will be a
pointer to a buffer of szPage bytes used to store the content of a
single database page. The pExtra element of sqlite3_pcache_page will be
a pointer to the szExtra bytes of extra storage that SQLite has requested
for each entry in the page cache.</p>
<p>The page to be fetched is determined by the key. The minimum key value
is 1. After it has been retrieved using xFetch, the page is considered
to be "pinned".</p>
<p>If the requested page is already in the page cache, then the page cache
implementation must return a pointer to the page buffer with its content
intact. If the requested page is not already in the cache, then the
cache implementation should use the value of the createFlag
parameter to help it determined what action to take:</p>
<p><table border=1 width=85% align=center>
<tr><th> createFlag <th> Behavior when page is not already in cache
<tr><td> 0 <td> Do not allocate a new page. Return NULL.
<tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
Otherwise return NULL.
<tr><td> 2 <td> Make every effort to allocate a new page. Only return
NULL if allocating a new page is effectively impossible.
</table></p>
<p>SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
will only use a createFlag of 2 after a prior call with a createFlag of 1
failed. In between the xFetch() calls, SQLite may
attempt to unpin one or more cache pages by spilling the content of
pinned pages to disk and synching the operating system disk cache.</p>
<p><a name="thexunpinpagecachemethod"></a>
xUnpin() is called by SQLite with a pointer to a currently pinned page
as its second argument. If the third parameter, discard, is non-zero,
then the page must be evicted from the cache.
If the discard parameter is
zero, then the page may be discarded or retained at the discretion of
page cache implementation. The page cache implementation
may choose to evict unpinned pages at any time.</p>
<p>The cache must not perform any reference counting. A single
call to xUnpin() unpins the page regardless of the number of prior calls
to xFetch().</p>
<p><a name="thexrekeypagecachemethods"></a>
The xRekey() method is used to change the key value associated with the
page passed as the second argument. If the cache
previously contains an entry associated with newKey, it must be
discarded. Any prior cache entry associated with newKey is guaranteed not
to be pinned.</p>
<p>When SQLite calls the xTruncate() method, the cache must discard all
existing cache entries with page numbers (keys) greater than or equal
to the value of the iLimit parameter passed to xTruncate(). If any
of these pages are pinned, they are implicitly unpinned, meaning that
they can be safely discarded.</p>
<p><a name="thexdestroypagecachemethod"></a>
The xDestroy() method is used to delete a cache allocated by xCreate().
All resources associated with the specified cache should be freed. After
calling the xDestroy() method, SQLite considers the <a href="#sqlite3_pcache">sqlite3_pcache*</a>
handle invalid, and will not use it with any other sqlite3_pcache_methods2
functions.</p>
<p><a name="thexshrinkpagecachemethod"></a>
SQLite invokes the xShrink() method when it wants the page cache to
free up as much of heap memory as possible. The page cache implementation
is not obligated to free any memory, but well-behaved implementations should
do their best.
</p><hr><a name="sqlite3_stmt"></a>
<h2>Prepared Statement Object</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_stmt sqlite3_stmt;
</pre></blockquote>
<p>
An instance of this object represents a single SQL statement that
has been compiled into binary form and is ready to be evaluated.</p>
<p>Think of each SQL statement as a separate computer program. The
original SQL text is source code. A prepared statement object
is the compiled object code. All SQL must be converted into a
prepared statement before it can be run.</p>
<p>The life-cycle of a prepared statement object usually goes like this:</p>
<p><ol>
<li> Create the prepared statement object using <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>.
<li> Bind values to <a href="lang_expr.html#varparam">parameters</a> using the sqlite3_bind_*()
interfaces.
<li> Run the SQL by calling <a href="#sqlite3_step">sqlite3_step()</a> one or more times.
<li> Reset the prepared statement using <a href="#sqlite3_reset">sqlite3_reset()</a> then go back
to step 2. Do this zero or more times.
<li> Destroy the object using <a href="#sqlite3_finalize">sqlite3_finalize()</a>.
</ol>
</p><p>6 Constructors using this object:
<div class='columns' style='columns: 17em auto;'>
<ul style='padding-top:0;'>
<li><a href='#sqlite3_prepare'>sqlite3_prepare</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare16</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v2</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v3</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v2</a></li>
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v3</a></li>
</ul>
</div>
</p>
<p>1 Destructor using this object: <a href="#sqlite3_finalize">sqlite3_finalize()</a></p>
<p>53 Methods using this object:
<div class='columns' style='columns: 17em auto;'>
<ul style='padding-top:0;'>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_blob</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_blob64</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_double</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_int</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_int64</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_null</a></li>
<li><a href='#sqlite3_bind_parameter_count'>sqlite3_bind_parameter_count</a></li>
<li><a href='#sqlite3_bind_parameter_index'>sqlite3_bind_parameter_index</a></li>
<li><a href='#sqlite3_bind_parameter_name'>sqlite3_bind_parameter_name</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_pointer</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text16</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text64</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_value</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_zeroblob</a></li>
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_zeroblob64</a></li>
<li><a href='#sqlite3_clear_bindings'>sqlite3_clear_bindings</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_blob</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_bytes</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_bytes16</a></li>
<li><a href='#sqlite3_column_count'>sqlite3_column_count</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_database_name</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_database_name16</a></li>
<li><a href='#sqlite3_column_decltype'>sqlite3_column_decltype</a></li>
<li><a href='#sqlite3_column_decltype'>sqlite3_column_decltype16</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_double</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_int</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_int64</a></li>
<li><a href='#sqlite3_column_name'>sqlite3_column_name</a></li>
<li><a href='#sqlite3_column_name'>sqlite3_column_name16</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_origin_name</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_origin_name16</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_table_name</a></li>
<li><a href='#sqlite3_column_database_name'>sqlite3_column_table_name16</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_text</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_text16</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_type</a></li>
<li><a href='#sqlite3_column_blob'>sqlite3_column_value</a></li>
<li><a href='#sqlite3_data_count'>sqlite3_data_count</a></li>
<li><a href='#sqlite3_db_handle'>sqlite3_db_handle</a></li>
<li><a href='#sqlite3_expanded_sql'>sqlite3_expanded_sql</a></li>
<li><a href='#sqlite3_expanded_sql'>sqlite3_normalized_sql</a></li>
<li><a href='#sqlite3_reset'>sqlite3_reset</a></li>
<li><a href='#sqlite3_expanded_sql'>sqlite3_sql</a></li>
<li><a href='#sqlite3_step'>sqlite3_step</a></li>
<li><a href='#sqlite3_stmt_busy'>sqlite3_stmt_busy</a></li>
<li><a href='#sqlite3_stmt_explain'>sqlite3_stmt_explain</a></li>
<li><a href='#sqlite3_stmt_isexplain'>sqlite3_stmt_isexplain</a></li>
<li><a href='#sqlite3_stmt_readonly'>sqlite3_stmt_readonly</a></li>
<li><a href='#sqlite3_stmt_scanstatus'>sqlite3_stmt_scanstatus</a></li>
<li><a href='#sqlite3_stmt_scanstatus_reset'>sqlite3_stmt_scanstatus_reset</a></li>
<li><a href='#sqlite3_stmt_scanstatus'>sqlite3_stmt_scanstatus_v2</a></li>
<li><a href='#sqlite3_stmt_status'>sqlite3_stmt_status</a></li>
</ul>
</div>
</p>
<hr><a name="sqlite3_value"></a>
<h2>Dynamically Typed Value Object</h2>
</div>
<blockquote><pre>
typedef struct sqlite3_value sqlite3_value;
</pre></blockquote>
<p>
SQLite uses the sqlite3_value object to represent all values
that can be stored in a database table. SQLite uses dynamic typing
for the values it stores. Values stored in sqlite3_value objects
can be integers, floating point values, strings, BLOBs, or NULL.</p>
<p>An sqlite3_value object may be either "protected" or "unprotected".
Some interfaces require a protected sqlite3_value. Other interfaces
will accept either a protected or an unprotected sqlite3_value.
Every interface that accepts sqlite3_value arguments specifies
whether or not it requires a protected sqlite3_value. The
<a href="#sqlite3_value_dup">sqlite3_value_dup()</a> interface can be used to construct a new
protected sqlite3_value from an unprotected sqlite3_value.</p>
<p>The terms "protected" and "unprotected" refer to whether or not
a mutex is held. An internal mutex is held for a protected
sqlite3_value object but no mutex is held for an unprotected
sqlite3_value object. If SQLite is compiled to be single-threaded
(with <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> and with <a href="#sqlite3_threadsafe">sqlite3_threadsafe()</a> returning 0)
or if SQLite is run in one of reduced mutex modes
<a href="#sqliteconfigsinglethread">SQLITE_CONFIG_SINGLETHREAD</a> or <a href="#sqliteconfigmultithread">SQLITE_CONFIG_MULTITHREAD</a>
then there is no distinction between protected and unprotected
sqlite3_value objects and they can be used interchangeably. However,
for maximum code portability it is recommended that applications
still make the distinction between protected and unprotected
sqlite3_value objects even when not strictly required.</p>
<p>The sqlite3_value objects that are passed as parameters into the
implementation of <a href="appfunc.html">application-defined SQL functions</a> are protected.
The sqlite3_value objects returned by <a href="#sqlite3_vtab_rhs_value">sqlite3_vtab_rhs_value()</a>
are protected.
The sqlite3_value object returned by
<a href="#sqlite3_column_blob">sqlite3_column_value()</a> is unprotected.
Unprotected sqlite3_value objects may only be used as arguments
to <a href="#sqlite3_result_blob">sqlite3_result_value()</a>, <a href="#sqlite3_bind_blob">sqlite3_bind_value()</a>, and
<a href="#sqlite3_value_dup">sqlite3_value_dup()</a>.
The <a href="#sqlite3_value_blob">sqlite3_value_type()</a> family of
interfaces require protected sqlite3_value objects.
</p><p>19 Methods using this object:
<div class='columns' style='columns: 17em auto;'>
<ul style='padding-top:0;'>
<li><a href='#sqlite3_value_blob'>sqlite3_value_blob</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_bytes</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_bytes16</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_double</a></li>
<li><a href='#sqlite3_value_dup'>sqlite3_value_dup</a></li>
<li><a href='#sqlite3_value_encoding'>sqlite3_value_encoding</a></li>
<li><a href='#sqlite3_value_dup'>sqlite3_value_free</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_frombind</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_int</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_int64</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_nochange</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_numeric_type</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_pointer</a></li>
<li><a href='#sqlite3_value_subtype'>sqlite3_value_subtype</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_text</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16be</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16le</a></li>
<li><a href='#sqlite3_value_blob'>sqlite3_value_type</a></li>
</ul>
</div>
</p>
<hr><a name="sqlite3_aggregate_count"></a>
<h2>Deprecated Functions</h2>
</div>
<blockquote><pre>
#ifndef SQLITE_OMIT_DEPRECATED
int sqlite3_aggregate_count(sqlite3_context*);
int sqlite3_expired(sqlite3_stmt*);
int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
int sqlite3_global_recover(void);
void sqlite3_thread_cleanup(void);
int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
void*,sqlite3_int64);
#endif
</pre></blockquote>
<p>
These functions are <a href="capi3ref.html">deprecated</a>. In order to maintain
backwards compatibility with older code, these functions continue
to be supported. However, new applications should avoid
the use of these functions. To encourage programmers to avoid
these functions, we will not explain what they do.
</p><hr><a name="sqlite3_backup_finish"></a>
<h2>Online Backup API.</h2>
</div>
<blockquote><pre>
sqlite3_backup *sqlite3_backup_init(
sqlite3 *pDest, /* Destination database handle */
const char *zDestName, /* Destination database name */
sqlite3 *pSource, /* Source database handle */
const char *zSourceName /* Source database name */
);
int sqlite3_backup_step(sqlite3_backup *p, int nPage);
int sqlite3_backup_finish(sqlite3_backup *p);
int sqlite3_backup_remaining(sqlite3_backup *p);
int sqlite3_backup_pagecount(sqlite3_backup *p);
</pre></blockquote>
<p>
The backup API copies the content of one database into another.
It is useful either for creating backups of databases or
for copying in-memory databases to or from persistent files.</p>
<p>See Also: <a href="backup.html">Using the SQLite Online Backup API</a></p>
<p>SQLite holds a write transaction open on the destination database file
for the duration of the backup operation.
The source database is read-locked only while it is being read;
it is not locked continuously for the entire backup operation.
Thus, the backup may be performed on a live source database without
preventing other database connections from
reading or writing to the source database while the backup is underway.</p>
<p>To perform a backup operation:
<ol>
<li><b>sqlite3_backup_init()</b> is called once to initialize the
backup,
<li><b>sqlite3_backup_step()</b> is called one or more times to transfer
the data between the two databases, and finally
<li><b>sqlite3_backup_finish()</b> is called to release all resources
associated with the backup operation.
</ol>
There should be exactly one call to sqlite3_backup_finish() for each
successful call to sqlite3_backup_init().</p>
<p><a name="sqlite3backupinit"></a>
<b>sqlite3_backup_init()</b></p>
<p>The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
<a href="#sqlite3">database connection</a> associated with the destination database
and the database name, respectively.
The database name is "main" for the main database, "temp" for the
temporary database, or the name specified after the AS keyword in
an <a href="lang_attach.html">ATTACH</a> statement for an attached database.
The S and M arguments passed to
sqlite3_backup_init(D,N,S,M) identify the <a href="#sqlite3">database connection</a>
and database name of the source database, respectively.
The source and destination <a href="#sqlite3">database connections</a> (parameters S and D)
must be different or else sqlite3_backup_init(D,N,S,M) will fail with
an error.</p>
<p>A call to sqlite3_backup_init() will fail, returning NULL, if
there is already a read or read-write transaction open on the
destination database.</p>
<p>If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
returned and an error code and error message are stored in the
destination <a href="#sqlite3">database connection</a> D.
The error code and message for the failed call to sqlite3_backup_init()
can be retrieved using the <a href="#sqlite3_errcode">sqlite3_errcode()</a>, <a href="#sqlite3_errcode">sqlite3_errmsg()</a>, and/or
<a href="#sqlite3_errcode">sqlite3_errmsg16()</a> functions.
A successful call to sqlite3_backup_init() returns a pointer to an
<a href="#sqlite3_backup">sqlite3_backup</a> object.
The <a href="#sqlite3_backup">sqlite3_backup</a> object may be used with the sqlite3_backup_step() and
sqlite3_backup_finish() functions to perform the specified backup
operation.</p>
<p><a name="sqlite3backupstep"></a>
<b>sqlite3_backup_step()</b></p>
<p>Function sqlite3_backup_step(B,N) will copy up to N pages between
the source and destination databases specified by <a href="#sqlite3_backup">sqlite3_backup</a> object B.
If N is negative, all remaining source pages are copied.
If sqlite3_backup_step(B,N) successfully copies N pages and there
are still more pages to be copied, then the function returns <a href="#SQLITE_ABORT">SQLITE_OK</a>.
If sqlite3_backup_step(B,N) successfully finishes copying all pages
from source to destination, then it returns <a href="#SQLITE_ABORT">SQLITE_DONE</a>.
If an error occurs while running sqlite3_backup_step(B,N),
then an <a href="rescode.html">error code</a> is returned. As well as <a href="#SQLITE_ABORT">SQLITE_OK</a> and
<a href="#SQLITE_ABORT">SQLITE_DONE</a>, a call to sqlite3_backup_step() may return <a href="#SQLITE_ABORT">SQLITE_READONLY</a>,
<a href="#SQLITE_ABORT">SQLITE_NOMEM</a>, <a href="#SQLITE_ABORT">SQLITE_BUSY</a>, <a href="#SQLITE_ABORT">SQLITE_LOCKED</a>, or an
<a href="#SQLITE_ABORT_ROLLBACK">SQLITE_IOERR_XXX</a> extended error code.</p>
<p>The sqlite3_backup_step() might return <a href="#SQLITE_ABORT">SQLITE_READONLY</a> if
<ol>
<li> the destination database was opened read-only, or
<li> the destination database is using write-ahead-log journaling
and the destination and source page sizes differ, or
<li> the destination database is an in-memory database and the
destination and source page sizes differ.
</ol></p>
<p>If sqlite3_backup_step() cannot obtain a required file-system lock, then
the <a href="#sqlite3_busy_handler">busy-handler function</a>
is invoked (if one is specified). If the
busy-handler returns non-zero before the lock is available, then
<a href="#SQLITE_ABORT">SQLITE_BUSY</a> is returned to the caller. In this case the call to
sqlite3_backup_step() can be retried later. If the source
<a href="#sqlite3">database connection</a>
is being used to write to the source database when sqlite3_backup_step()
is called, then <a href="#SQLITE_ABORT">SQLITE_LOCKED</a> is returned immediately. Again, in this
case the call to sqlite3_backup_step() can be retried later on. If
<a href="#SQLITE_ABORT_ROLLBACK">SQLITE_IOERR_XXX</a>, <a href="#SQLITE_ABORT">SQLITE_NOMEM</a>, or
<a href="#SQLITE_ABORT">SQLITE_READONLY</a> is returned, then
there is no point in retrying the call to sqlite3_backup_step(). These
errors are considered fatal. The application must accept
that the backup operation has failed and pass the backup operation handle
to the sqlite3_backup_finish() to release associated resources.</p>
<p>The first call to sqlite3_backup_step() obtains an exclusive lock
on the destination file. The exclusive lock is not released until either
sqlite3_backup_finish() is called or the backup operation is complete
and sqlite3_backup_step() returns <a href="#SQLITE_ABORT">SQLITE_DONE</a>. Every call to
sqlite3_backup_step() obtains a <a href="lockingv3.html#shared_lock">shared lock</a> on the source database that
lasts for the duration of the sqlite3_backup_step() call.
Because the source database is not locked between calls to
sqlite3_backup_step(), the source database may be modified mid-way
through the backup process. If the source database is modified by an
external process or via a database connection other than the one being
used by the backup operation, then the backup will be automatically
restarted by the next call to sqlite3_backup_step(). If the source
database is modified by the using the same database connection as is used
by the backup operation, then the backup database is automatically
updated at the same time.</p>
<p><a name="sqlite3backupfinish"></a>
<b>sqlite3_backup_finish()</b></p>
<p>When sqlite3_backup_step() has returned <a href="#SQLITE_ABORT">SQLITE_DONE</a>, or when the
application wishes to abandon the backup operation, the application
should destroy the <a href="#sqlite3_backup">sqlite3_backup</a> by passing it to sqlite3_backup_finish().
The sqlite3_backup_finish() interfaces releases all
resources associated with the <a href="#sqlite3_backup">sqlite3_backup</a> object.
If sqlite3_backup_step() has not yet returned <a href="#SQLITE_ABORT">SQLITE_DONE</a>, then any
active write-transaction on the destination database is rolled back.
The <a href="#sqlite3_backup">sqlite3_backup</a> object is invalid
and may not be used following a call to sqlite3_backup_finish().</p>
<p>The value returned by sqlite3_backup_finish is <a href="#SQLITE_ABORT">SQLITE_OK</a> if no
sqlite3_backup_step() errors occurred, regardless or whether or not
sqlite3_backup_step() completed.
If an out-of-memory condition or IO error occurred during any prior
sqlite3_backup_step() call on the same <a href="#sqlite3_backup">sqlite3_backup</a> object, then
sqlite3_backup_finish() returns the corresponding <a href="rescode.html">error code</a>.</p>
<p>A return of <a href="#SQLITE_ABORT">SQLITE_BUSY</a> or <a href="#SQLITE_ABORT">SQLITE_LOCKED</a> from sqlite3_backup_step()
is not a permanent error and does not affect the return value of
sqlite3_backup_finish().</p>
<p><a name="sqlite3backupremaining"></a>
<a name="sqlite3backuppagecount"></a>
<b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b></p>
<p>The sqlite3_backup_remaining() routine returns the number of pages still
to be backed up at the conclusion of the most recent sqlite3_backup_step().
The sqlite3_backup_pagecount() routine returns the total number of pages
in the source database at the conclusion of the most recent
sqlite3_backup_step().
The values returned by these functions are only updated by
sqlite3_backup_step(). If the source database is modified in a way that
changes the size of the source database or the number of pages remaining,
those changes are not reflected in the output of sqlite3_backup_pagecount()
and sqlite3_backup_remaining() until after the next
sqlite3_backup_step().</p>
<p><b>Concurrent Usage of Database Handles</b></p>
<p>The source <a href="#sqlite3">database connection</a> may be used by the application for other
purposes while a backup operation is underway or being initialized.
If SQLite is compiled and configured to support threadsafe database
connections, then the source database connection may be used concurrently
from within other threads.</p>
<p>However, the application must guarantee that the destination
<a href="#sqlite3">database connection</a> is not passed to any other API (by any thread) after
sqlite3_backup_init() is called and before the corresponding call to
sqlite3_backup_finish(). SQLite does not currently check to see
if the application incorrectly accesses the destination <a href="#sqlite3">database connection</a>
and so no error code is reported, but the operations may malfunction
nevertheless. Use of the destination database connection while a
backup is in progress might also cause a mutex deadlock.</p>
<p>If running in <a href="sharedcache.html">shared cache mode</a>, the application must
guarantee that the shared cache used by the destination database
is not accessed while the backup is running. In practice this means
that the application must guarantee that the disk file being
backed up to is not accessed by any connection within the process,
not just the specific connection that was passed to sqlite3_backup_init().</p>
<p>The <a href="#sqlite3_backup">sqlite3_backup</a> object itself is partially threadsafe. Multiple
threads may safely make multiple concurrent calls to sqlite3_backup_step().
However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
APIs are not strictly speaking threadsafe. If they are invoked at the
same time as another thread is invoking sqlite3_backup_step() it is
possible that they return invalid values.
</p><hr><a name="sqlite3_changes"></a>
<h2>Count The Number Of Rows Modified</h2>
</div>
<blockquote><pre>
int sqlite3_changes(sqlite3*);
sqlite3_int64 sqlite3_changes64(sqlite3*);
</pre></blockquote>
<p>
These functions return the number of rows modified, inserted or
deleted by the most recently completed INSERT, UPDATE or DELETE
statement on the database connection specified by the only parameter.
The two functions are identical except for the type of the return value
and that if the number of rows modified by the most recent INSERT, UPDATE
or DELETE is greater than the maximum value supported by type "int", then
the return value of sqlite3_changes() is undefined. Executing any other
type of SQL statement does not modify the value returned by these functions.</p>
<p>Only changes made directly by the INSERT, UPDATE or DELETE statement are
considered - auxiliary changes caused by <a href="lang_createtrigger.html">triggers</a>,
<a href="foreignkeys.html#fk_actions">foreign key actions</a> or <a href="lang_replace.html">REPLACE</a> constraint resolution are not counted.</p>
<p>Changes to a view that are intercepted by
<a href="lang_createtrigger.html#instead_of_trigger">INSTEAD OF triggers</a> are not counted. The value
returned by sqlite3_changes() immediately after an INSERT, UPDATE or
DELETE statement run on a view is always zero. Only changes made to real
tables are counted.</p>
<p>Things are more complicated if the sqlite3_changes() function is
executed while a trigger program is running. This may happen if the
program uses the <a href="lang_corefunc.html#changes">changes() SQL function</a>, or if some other callback
function invokes sqlite3_changes() directly. Essentially:</p>
<p><ul>
<li> Before entering a trigger program the value returned by
sqlite3_changes() function is saved. After the trigger program
has finished, the original value is restored.</p>
<p><li> Within a trigger program each INSERT, UPDATE and DELETE
statement sets the value returned by sqlite3_changes()
upon completion as normal. Of course, this value will not include
any changes performed by sub-triggers, as the sqlite3_changes()
value will be saved and restored after each sub-trigger has run.
</ul></p>
<p>This means that if the changes() SQL function (or similar) is used
by the first INSERT, UPDATE or DELETE statement within a trigger, it
returns the value as set when the calling statement began executing.
If it is used by the second or subsequent such statement within a trigger
program, the value returned reflects the number of rows modified by the
previous INSERT, UPDATE or DELETE statement within the same trigger.</p>
<p>If a separate thread makes changes on the same database connection
while <a href="#sqlite3_changes">sqlite3_changes()</a> is running then the value returned
is unpredictable and not meaningful.</p>
<p>See also:
<ul>
<li> the <a href="#sqlite3_total_changes">sqlite3_total_changes()</a> interface
<li> the <a href="pragma.html#pragma_count_changes">count_changes pragma</a>
<li> the <a href="lang_corefunc.html#changes">changes() SQL function</a>
<li> the <a href="pragma.html#pragma_data_version">data_version pragma</a>
</ul>
</p><hr><a name="sqlite3_close"></a>
<h2>Closing A Database Connection</h2>
</div>
<blockquote><pre>
int sqlite3_close(sqlite3*);
int sqlite3_close_v2(sqlite3*);
</pre></blockquote>
<p>
The sqlite3_close() and sqlite3_close_v2() routines are destructors
for the <a href="#sqlite3">sqlite3</a> object.
Calls to sqlite3_close() and sqlite3_close_v2() return <a href="#SQLITE_ABORT">SQLITE_OK</a> if
the <a href="#sqlite3">sqlite3</a> object is successfully destroyed and all associated
resources are deallocated.</p>
<p>Ideally, applications should <a href="#sqlite3_finalize">finalize</a> all
<a href="#sqlite3_stmt">prepared statements</a>, <a href="#sqlite3_blob_close">close</a> all <a href="#sqlite3_blob">BLOB handles</a>, and
<a href="#sqlite3backupfinish">finish</a> all <a href="#sqlite3_backup">sqlite3_backup</a> objects associated
with the <a href="#sqlite3">sqlite3</a> object prior to attempting to close the object.
If the database connection is associated with unfinalized prepared
statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
sqlite3_close() will leave the database connection open and return
<a href="#SQLITE_ABORT">SQLITE_BUSY</a>. If sqlite3_close_v2() is called with unfinalized prepared
statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
it returns <a href="#SQLITE_ABORT">SQLITE_OK</a> regardless, but instead of deallocating the database
connection immediately, it marks the database connection as an unusable
"zombie" and makes arrangements to automatically deallocate the database
connection after all prepared statements are finalized, all BLOB handles
are closed, and all backups have finished. The sqlite3_close_v2() interface
is intended for use with host languages that are garbage collected, and
where the order in which destructors are called is arbitrary.</p>
<p>If an <a href="#sqlite3">sqlite3</a> object is destroyed while a transaction is open,
the transaction is automatically rolled back.</p>
<p>The C parameter to <a href="#sqlite3_close">sqlite3_close(C)</a> and <a href="#sqlite3_close">sqlite3_close_v2(C)</a>
must be either a NULL
pointer or an <a href="#sqlite3">sqlite3</a> object pointer obtained
from <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open16()</a>, or
<a href="#sqlite3_open">sqlite3_open_v2()</a>, and not previously closed.
Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
argument is a harmless no-op.
</p><hr><a name="sqlite3_collation_needed"></a>
<h2>Collation Needed Callbacks</h2>
</div>
<blockquote><pre>
int sqlite3_collation_needed(
sqlite3*,
void*,
void(*)(void*,sqlite3*,int eTextRep,const char*)
);
int sqlite3_collation_needed16(
sqlite3*,
void*,
void(*)(void*,sqlite3*,int eTextRep,const void*)
);
</pre></blockquote>
<p>
To avoid having to register all collation sequences before a database
can be used, a single callback function may be registered with the
<a href="#sqlite3">database connection</a> to be invoked whenever an undefined collation
sequence is required.</p>
<p>If the function is registered using the sqlite3_collation_needed() API,
then it is passed the names of undefined collation sequences as strings
encoded in UTF-8. If sqlite3_collation_needed16() is used,
the names are passed as UTF-16 in machine native byte order.
A call to either function replaces the existing collation-needed callback.</p>
<p>When the callback is invoked, the first argument passed is a copy
of the second argument to sqlite3_collation_needed() or
sqlite3_collation_needed16(). The second argument is the database
connection. The third argument is one of <a href="#SQLITE_ANY">SQLITE_UTF8</a>, <a href="#SQLITE_ANY">SQLITE_UTF16BE</a>,
or <a href="#SQLITE_ANY">SQLITE_UTF16LE</a>, indicating the most desirable form of the collation
sequence function required. The fourth parameter is the name of the
required collation sequence.</p>
<p>The callback function should register the desired collation using
<a href="#sqlite3_create_collation">sqlite3_create_collation()</a>, <a href="#sqlite3_create_collation">sqlite3_create_collation16()</a>, or
<a href="#sqlite3_create_collation">sqlite3_create_collation_v2()</a>.
</p><hr><a name="sqlite3_column_database_name"></a>
<h2>Source Of Data In A Query Result</h2>
</div>
<blockquote><pre>
const char *sqlite3_column_database_name(sqlite3_stmt*,int);
const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
const char *sqlite3_column_table_name(sqlite3_stmt*,int);
const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
</pre></blockquote>
<p>
These routines provide a means to determine the database, table, and
table column that is the origin of a particular result column in
<a href="lang_select.html">SELECT</a> statement.
The name of the database or table or column can be returned as
either a UTF-8 or UTF-16 string. The _database_ routines return
the database name, the _table_ routines return the table name, and
the origin_ routines return the column name.
The returned string is valid until the <a href="#sqlite3_stmt">prepared statement</a> is destroyed
using <a href="#sqlite3_finalize">sqlite3_finalize()</a> or until the statement is automatically
reprepared by the first call to <a href="#sqlite3_step">sqlite3_step()</a> for a particular run
or until the same information is requested
again in a different encoding.</p>
<p>The names returned are the original un-aliased names of the
database, table, and column.</p>
<p>The first argument to these interfaces is a <a href="#sqlite3_stmt">prepared statement</a>.
These functions return information about the Nth result column returned by
the statement, where N is the second function argument.
The left-most column is column 0 for these routines.</p>
<p>If the Nth column returned by the statement is an expression or
subquery and is not a column value, then all of these functions return
NULL. These routines might also return NULL if a memory allocation error
occurs. Otherwise, they return the name of the attached database, table,
or column that query result column was extracted from.</p>
<p>As with all other SQLite APIs, those whose names end with "16" return
UTF-16 encoded strings and the other functions return UTF-8.</p>
<p>These APIs are only available if the library was compiled with the
<a href="compile.html#enable_column_metadata">SQLITE_ENABLE_COLUMN_METADATA</a> C-preprocessor symbol.</p>
<p>If two or more threads call one or more
<a href="#sqlite3_column_database_name">column metadata interfaces</a>
for the same <a href="#sqlite3_stmt">prepared statement</a> and result column
at the same time then the results are undefined.
</p><hr><a name="sqlite3_column_decltype"></a>
<h2>Declared Datatype Of A Query Result</h2>
</div>
<blockquote><pre>
const char *sqlite3_column_decltype(sqlite3_stmt*,int);
const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
</pre></blockquote>
<p>
The first parameter is a <a href="#sqlite3_stmt">prepared statement</a>.
If this statement is a <a href="lang_select.html">SELECT</a> statement and the Nth column of the
returned result set of that <a href="lang_select.html">SELECT</a> is a table column (not an
expression or subquery) then the declared type of the table
column is returned. If the Nth column of the result set is an
expression or subquery, then a NULL pointer is returned.
The returned string is always UTF-8 encoded.</p>
<p>For example, given the database schema:</p>
<p>CREATE TABLE t1(c1 VARIANT);</p>
<p>and the following statement to be compiled:</p>
<p>SELECT c1 + 1, c1 FROM t1;</p>
<p>this routine would return the string "VARIANT" for the second result
column (i==1), and a NULL pointer for the first result column (i==0).</p>
<p>SQLite uses dynamic run-time typing. So just because a column
is declared to contain a particular type does not mean that the
data stored in that column is of the declared type. SQLite is
strongly typed, but the typing is dynamic not static. Type
is associated with individual values, not with the containers
used to hold those values.
</p><hr><a name="sqlite3_column_name"></a>
<h2>Column Names In A Result Set</h2>
</div>
<blockquote><pre>
const char *sqlite3_column_name(sqlite3_stmt*, int N);
const void *sqlite3_column_name16(sqlite3_stmt*, int N);
</pre></blockquote>
<p>
These routines return the name assigned to a particular column
in the result set of a <a href="lang_select.html">SELECT</a> statement. The sqlite3_column_name()
interface returns a pointer to a zero-terminated UTF-8 string
and sqlite3_column_name16() returns a pointer to a zero-terminated
UTF-16 string. The first parameter is the <a href="#sqlite3_stmt">prepared statement</a>
that implements the <a href="lang_select.html">SELECT</a> statement. The second parameter is the
column number. The leftmost column is number 0.</p>
<p>The returned string pointer is valid until either the <a href="#sqlite3_stmt">prepared statement</a>
is destroyed by <a href="#sqlite3_finalize">sqlite3_finalize()</a> or until the statement is automatically
reprepared by the first call to <a href="#sqlite3_step">sqlite3_step()</a> for a particular run
or until the next call to
sqlite3_column_name() or sqlite3_column_name16() on the same column.</p>
<p>If sqlite3_malloc() fails during the processing of either routine
(for example during a conversion from UTF-8 to UTF-16) then a
NULL pointer is returned.</p>
<p>The name of a result column is the value of the "AS" clause for
that column, if there is an AS clause. If there is no AS clause
then the name of the column is unspecified and may change from
one release of SQLite to the next.
</p><hr><a name="sqlite3_commit_hook"></a>
<h2>Commit And Rollback Notification Callbacks</h2>
</div>
<blockquote><pre>
void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
</pre></blockquote>
<p>
The sqlite3_commit_hook() interface registers a callback
function to be invoked whenever a transaction is <a href="lang_transaction.html">committed</a>.
Any callback set by a previous call to sqlite3_commit_hook()
for the same database connection is overridden.
The sqlite3_rollback_hook() interface registers a callback
function to be invoked whenever a transaction is <a href="lang_transaction.html">rolled back</a>.
Any callback set by a previous call to sqlite3_rollback_hook()
for the same database connection is overridden.
The pArg argument is passed through to the callback.
If the callback on a commit hook function returns non-zero,
then the commit is converted into a rollback.</p>
<p>The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
return the P argument from the previous call of the same function
on the same <a href="#sqlite3">database connection</a> D, or NULL for
the first call for each function on D.</p>
<p>The commit and rollback hook callbacks are not reentrant.
The callback implementation must not do anything that will modify
the database connection that invoked the callback. Any actions
to modify the database connection must be deferred until after the
completion of the <a href="#sqlite3_step">sqlite3_step()</a> call that triggered the commit
or rollback hook in the first place.
Note that running any other SQL statements, including SELECT statements,
or merely calling <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> and <a href="#sqlite3_step">sqlite3_step()</a> will modify
the database connections for the meaning of "modify" in this paragraph.</p>
<p>Registering a NULL function disables the callback.</p>
<p>When the commit hook callback routine returns zero, the <a href="lang_transaction.html">COMMIT</a>
operation is allowed to continue normally. If the commit hook
returns non-zero, then the <a href="lang_transaction.html">COMMIT</a> is converted into a <a href="lang_transaction.html">ROLLBACK</a>.
The rollback hook is invoked on a rollback that results from a commit
hook returning non-zero, just as it would be with any other rollback.</p>
<p>For the purposes of this API, a transaction is said to have been
rolled back if an explicit "ROLLBACK" statement is executed, or
an error or constraint causes an implicit rollback to occur.
The rollback callback is not invoked if a transaction is
automatically rolled back because the database connection is closed.</p>
<p>See also the <a href="#sqlite3_update_hook">sqlite3_update_hook()</a> interface.
</p><hr><a name="sqlite3_compileoption_get"></a>
<h2>Run-Time Library Compilation Options Diagnostics</h2>
</div>
<blockquote><pre>
#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
int sqlite3_compileoption_used(const char *zOptName);
const char *sqlite3_compileoption_get(int N);
#else
# define sqlite3_compileoption_used(X) 0
# define sqlite3_compileoption_get(X) ((void*)0)
#endif
</pre></blockquote>
<p>
The sqlite3_compileoption_used() function returns 0 or 1
indicating whether the specified option was defined at
compile time. The SQLITE_ prefix may be omitted from the
option name passed to sqlite3_compileoption_used().</p>
<p>The sqlite3_compileoption_get() function allows iterating
over the list of options that were defined at compile time by
returning the N-th compile time option string. If N is out of range,
sqlite3_compileoption_get() returns a NULL pointer. The SQLITE_
prefix is omitted from any strings returned by
sqlite3_compileoption_get().</p>
<p>Support for the diagnostic functions sqlite3_compileoption_used()
and sqlite3_compileoption_get() may be omitted by specifying the
<a href="compile.html#omit_compileoption_diags">SQLITE_OMIT_COMPILEOPTION_DIAGS</a> option at compile time.</p>
<p>See also: SQL functions <a href="lang_corefunc.html#sqlite_compileoption_used">sqlite_compileoption_used()</a> and
<a href="lang_corefunc.html#sqlite_compileoption_get">sqlite_compileoption_get()</a> and the <a href="pragma.html#pragma_compile_options">compile_options pragma</a>.
</p><hr><a name="sqlite3_complete"></a>
<h2>Determine If An SQL Statement Is Complete</h2>
</div>
<blockquote><pre>
int sqlite3_complete(const char *sql);
int sqlite3_complete16(const void *sql);
</pre></blockquote>
<p>
These routines are useful during command-line input to determine if the
currently entered text seems to form a complete SQL statement or
if additional input is needed before sending the text into
SQLite for parsing. These routines return 1 if the input string
appears to be a complete SQL statement. A statement is judged to be
complete if it ends with a semicolon token and is not a prefix of a
well-formed CREATE TRIGGER statement. Semicolons that are embedded within
string literals or quoted identifier names or comments are not
independent tokens (they are part of the token in which they are
embedded) and thus do not count as a statement terminator. Whitespace
and comments that follow the final semicolon are ignored.</p>
<p>These routines return 0 if the statement is incomplete. If a
memory allocation fails, then SQLITE_NOMEM is returned.</p>
<p>These routines do not parse the SQL statements thus
will not detect syntactically incorrect SQL.</p>
<p>If SQLite has not been initialized using <a href="#sqlite3_initialize">sqlite3_initialize()</a> prior
to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
automatically by sqlite3_complete16(). If that initialization fails,
then the return value from sqlite3_complete16() will be non-zero
regardless of whether or not the input SQL is complete.</p>
<p>The input to <a href="#sqlite3_complete">sqlite3_complete()</a> must be a zero-terminated
UTF-8 string.</p>
<p>The input to <a href="#sqlite3_complete">sqlite3_complete16()</a> must be a zero-terminated
UTF-16 string in native byte order.
</p><hr><a name="sqlite3_create_collation"></a>
<h2>Define New Collating Sequences</h2>
</div>
<blockquote><pre>
int sqlite3_create_collation(
sqlite3*,
const char *zName,
int eTextRep,
void *pArg,
int(*xCompare)(void*,int,const void*,int,const void*)
);
int sqlite3_create_collation_v2(
sqlite3*,
const char *zName,
int eTextRep,
void *pArg,
int(*xCompare)(void*,int,const void*,int,const void*),
void(*xDestroy)(void*)
);
int sqlite3_create_collation16(
sqlite3*,
const void *zName,
int eTextRep,
void *pArg,
int(*xCompare)(void*,int,const void*,int,const void*)
);
</pre></blockquote>
<p>
These functions add, remove, or modify a <a href="datatype3.html#collation">collation</a> associated
with the <a href="#sqlite3">database connection</a> specified as the first argument.</p>
<p>The name of the collation is a UTF-8 string
for sqlite3_create_collation() and sqlite3_create_collation_v2()
and a UTF-16 string in native byte order for sqlite3_create_collation16().
Collation names that compare equal according to <a href="#sqlite3_stricmp">sqlite3_strnicmp()</a> are
considered to be the same name.</p>
<p>The third argument (eTextRep) must be one of the constants:
<ul>
<li> <a href="#SQLITE_ANY">SQLITE_UTF8</a>,
<li> <a href="#SQLITE_ANY">SQLITE_UTF16LE</a>,
<li> <a href="#SQLITE_ANY">SQLITE_UTF16BE</a>,
<li> <a href="#SQLITE_ANY">SQLITE_UTF16</a>, or
<li> <a href="#SQLITE_ANY">SQLITE_UTF16_ALIGNED</a>.
</ul>
The eTextRep argument determines the encoding of strings passed
to the collating function callback, xCompare.
The <a href="#SQLITE_ANY">SQLITE_UTF16</a> and <a href="#SQLITE_ANY">SQLITE_UTF16_ALIGNED</a> values for eTextRep
force strings to be UTF16 with native byte order.
The <a href="#SQLITE_ANY">SQLITE_UTF16_ALIGNED</a> value for eTextRep forces strings to begin
on an even byte address.</p>
<p>The fourth argument, pArg, is an application data pointer that is passed
through as the first argument to the collating function callback.</p>
<p>The fifth argument, xCompare, is a pointer to the collating function.
Multiple collating functions can be registered using the same name but
with different eTextRep parameters and SQLite will use whichever
function requires the least amount of data transformation.
If the xCompare argument is NULL then the collating function is
deleted. When all collating functions having the same name are deleted,
that collation is no longer usable.</p>
<p>The collating function callback is invoked with a copy of the pArg
application data pointer and with two strings in the encoding specified
by the eTextRep argument. The two integer parameters to the collating
function callback are the length of the two strings, in bytes. The collating
function must return an integer that is negative, zero, or positive
if the first string is less than, equal to, or greater than the second,
respectively. A collating function must always return the same answer
given the same inputs. If two or more collating functions are registered
to the same collation name (using different eTextRep values) then all
must give an equivalent answer when invoked with equivalent strings.
The collating function must obey the following properties for all
strings A, B, and C:</p>
<p><ol>
<li> If A==B then B==A.
<li> If A==B and B==C then A==C.
<li> If A<B THEN B>A.
<li> If A<B and B<C then A<C.
</ol></p>
<p>If a collating function fails any of the above constraints and that
collating function is registered and used, then the behavior of SQLite
is undefined.</p>
<p>The sqlite3_create_collation_v2() works like sqlite3_create_collation()
with the addition that the xDestroy callback is invoked on pArg when
the collating function is deleted.
Collating functions are deleted when they are overridden by later
calls to the collation creation functions or when the
<a href="#sqlite3">database connection</a> is closed using <a href="#sqlite3_close">sqlite3_close()</a>.</p>
<p>The xDestroy callback is <u>not</u> called if the
sqlite3_create_collation_v2() function fails. Applications that invoke
sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
check the return code and dispose of the application data pointer
themselves rather than expecting SQLite to deal with it for them.
This is different from every other SQLite interface. The inconsistency
is unfortunate but cannot be changed without breaking backwards
compatibility.</p>
<p>See also: <a href="#sqlite3_collation_needed">sqlite3_collation_needed()</a> and <a href="#sqlite3_collation_needed">sqlite3_collation_needed16()</a>.
</p><hr><a name="sqlite3_create_filename"></a>
<h2>Create and Destroy VFS Filenames</h2>
</div>
<blockquote><pre>
sqlite3_filename sqlite3_create_filename(
const char *zDatabase,
const char *zJournal,
const char *zWal,
int nParam,
const char **azParam
);
void sqlite3_free_filename(sqlite3_filename);
</pre></blockquote>
<p>
These interfaces are provided for use by <a href="vfs.html#shim">VFS shim</a> implementations and
are not useful outside of that context.</p>
<p>The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
database filename D with corresponding journal file J and WAL file W and
with N URI parameters key/values pairs in the array P. The result from
sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
is safe to pass to routines like:
<ul>
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_parameter()</a>,
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_boolean()</a>,
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_int64()</a>,
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_key()</a>,
<li> <a href="#sqlite3_filename_database">sqlite3_filename_database()</a>,
<li> <a href="#sqlite3_filename_database">sqlite3_filename_journal()</a>, or
<li> <a href="#sqlite3_filename_database">sqlite3_filename_wal()</a>.
</ul>
If a memory allocation error occurs, sqlite3_create_filename() might
return a NULL pointer. The memory obtained from sqlite3_create_filename(X)
must be released by a corresponding call to sqlite3_free_filename(Y).</p>
<p>The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
of 2*N pointers to strings. Each pair of pointers in this array corresponds
to a key and value for a query parameter. The P parameter may be a NULL
pointer if N is zero. None of the 2*N pointers in the P array may be
NULL pointers and key pointers should not be empty strings.
None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
be NULL pointers, though they can be empty strings.</p>
<p>The sqlite3_free_filename(Y) routine releases a memory allocation
previously obtained from sqlite3_create_filename(). Invoking
sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.</p>
<p>If the Y parameter to sqlite3_free_filename(Y) is anything other
than a NULL pointer or a pointer previously acquired from
sqlite3_create_filename(), then bad things such as heap
corruption or segfaults may occur. The value Y should not be
used again after sqlite3_free_filename(Y) has been called. This means
that if the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen()</a> method of a VFS has been called using Y,
then the corresponding [sqlite3_module.xClose() method should also be
invoked prior to calling sqlite3_free_filename(Y).
</p><hr><a name="sqlite3_create_module"></a>
<h2>Register A Virtual Table Implementation</h2>
</div>
<blockquote><pre>
int sqlite3_create_module(
sqlite3 *db, /* SQLite connection to register module with */
const char *zName, /* Name of the module */
const sqlite3_module *p, /* Methods for the module */
void *pClientData /* Client data for xCreate/xConnect */
);
int sqlite3_create_module_v2(
sqlite3 *db, /* SQLite connection to register module with */
const char *zName, /* Name of the module */
const sqlite3_module *p, /* Methods for the module */
void *pClientData, /* Client data for xCreate/xConnect */
void(*xDestroy)(void*) /* Module destructor function */
);
</pre></blockquote>
<p>
These routines are used to register a new <a href="#sqlite3_module">virtual table module</a> name.
Module names must be registered before
creating a new <a href="vtab.html">virtual table</a> using the module and before using a
preexisting <a href="vtab.html">virtual table</a> for the module.</p>
<p>The module name is registered on the <a href="#sqlite3">database connection</a> specified
by the first parameter. The name of the module is given by the
second parameter. The third parameter is a pointer to
the implementation of the <a href="#sqlite3_module">virtual table module</a>. The fourth
parameter is an arbitrary client data pointer that is passed through
into the <a href="vtab.html#xcreate">xCreate</a> and <a href="vtab.html#xconnect">xConnect</a> methods of the virtual table module
when a new virtual table is be being created or reinitialized.</p>
<p>The sqlite3_create_module_v2() interface has a fifth parameter which
is a pointer to a destructor for the pClientData. SQLite will
invoke the destructor function (if it is not NULL) when SQLite
no longer needs the pClientData pointer. The destructor will also
be invoked if the call to sqlite3_create_module_v2() fails.
The sqlite3_create_module()
interface is equivalent to sqlite3_create_module_v2() with a NULL
destructor.</p>
<p>If the third parameter (the pointer to the sqlite3_module object) is
NULL then no new module is created and any existing modules with the
same name are dropped.</p>
<p>See also: <a href="#sqlite3_drop_modules">sqlite3_drop_modules()</a>
</p><hr><a name="sqlite3_errcode"></a>
<h2>Error Codes And Messages</h2>
</div>
<blockquote><pre>
int sqlite3_errcode(sqlite3 *db);
int sqlite3_extended_errcode(sqlite3 *db);
const char *sqlite3_errmsg(sqlite3*);
const void *sqlite3_errmsg16(sqlite3*);
const char *sqlite3_errstr(int);
int sqlite3_error_offset(sqlite3 *db);
</pre></blockquote>
<p>
If the most recent sqlite3_* API call associated with
<a href="#sqlite3">database connection</a> D failed, then the sqlite3_errcode(D) interface
returns the numeric <a href="rescode.html">result code</a> or <a href="rescode.html#extrc">extended result code</a> for that
API call.
The sqlite3_extended_errcode()
interface is the same except that it always returns the
<a href="rescode.html#extrc">extended result code</a> even when extended result codes are
disabled.</p>
<p>The values returned by sqlite3_errcode() and/or
sqlite3_extended_errcode() might change with each API call.
Except, there are some interfaces that are guaranteed to never
change the value of the error code. The error-code preserving
interfaces include the following:</p>
<p><ul>
<li> sqlite3_errcode()
<li> sqlite3_extended_errcode()
<li> sqlite3_errmsg()
<li> sqlite3_errmsg16()
<li> sqlite3_error_offset()
</ul></p>
<p>The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
text that describes the error, as either UTF-8 or UTF-16 respectively,
or NULL if no error message is available.
(See how SQLite handles <a href="invalidutf.html">invalid UTF</a> for exceptions to this rule.)
Memory to hold the error message string is managed internally.
The application does not need to worry about freeing the result.
However, the error string might be overwritten or deallocated by
subsequent calls to other SQLite interface functions.</p>
<p>The sqlite3_errstr(E) interface returns the English-language text
that describes the <a href="rescode.html">result code</a> E, as UTF-8, or NULL if E is not an
result code for which a text error message is available.
Memory to hold the error message string is managed internally
and must not be freed by the application.</p>
<p>If the most recent error references a specific token in the input
SQL, the sqlite3_error_offset() interface returns the byte offset
of the start of that token. The byte offset returned by
sqlite3_error_offset() assumes that the input SQL is UTF8.
If the most recent error does not reference a specific token in the input
SQL, then the sqlite3_error_offset() function returns -1.</p>
<p>When the serialized <a href="threadsafe.html">threading mode</a> is in use, it might be the
case that a second error occurs on a separate thread in between
the time of the first error and the call to these interfaces.
When that happens, the second error will be reported since these
interfaces always report the most recent result. To avoid
this, each thread can obtain exclusive use of the <a href="#sqlite3">database connection</a> D
by invoking <a href="#sqlite3_mutex_alloc">sqlite3_mutex_enter</a>(<a href="#sqlite3_db_mutex">sqlite3_db_mutex</a>(D)) before beginning
to use D and invoking <a href="#sqlite3_mutex_alloc">sqlite3_mutex_leave</a>(<a href="#sqlite3_db_mutex">sqlite3_db_mutex</a>(D)) after
all calls to the interfaces listed here are completed.</p>
<p>If an interface fails with SQLITE_MISUSE, that means the interface
was invoked incorrectly by the application. In that case, the
error code and message may or may not be set.
</p><hr><a name="sqlite3_expanded_sql"></a>
<h2>Retrieving Statement SQL</h2>
</div>
<blockquote><pre>
const char *sqlite3_sql(sqlite3_stmt *pStmt);
char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
#ifdef SQLITE_ENABLE_NORMALIZE
const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
#endif
</pre></blockquote>
<p>
The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
SQL text used to create <a href="#sqlite3_stmt">prepared statement</a> P if P was
created by <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>, <a href="#sqlite3_prepare">sqlite3_prepare_v3()</a>,
<a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a>, or <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a>.
The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
string containing the SQL text of prepared statement P with
<a href="lang_expr.html#varparam">bound parameters</a> expanded.
The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
string containing the normalized SQL text of prepared statement P. The
semantics used to normalize a SQL statement are unspecified and subject
to change. At a minimum, literal values will be replaced with suitable
placeholders.</p>
<p>For example, if a prepared statement is created using the SQL
text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
and parameter :xyz is unbound, then sqlite3_sql() will return
the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
will return "SELECT 2345,NULL".</p>
<p>The sqlite3_expanded_sql() interface returns NULL if insufficient memory
is available to hold the result, or if the result would exceed the
the maximum string length determined by the <a href="#sqlitelimitlength">SQLITE_LIMIT_LENGTH</a>.</p>
<p>The <a href="compile.html#trace_size_limit">SQLITE_TRACE_SIZE_LIMIT</a> compile-time option limits the size of
bound parameter expansions. The <a href="compile.html#omit_trace">SQLITE_OMIT_TRACE</a> compile-time
option causes sqlite3_expanded_sql() to always return NULL.</p>
<p>The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
are managed by SQLite and are automatically freed when the prepared
statement is finalized.
The string returned by sqlite3_expanded_sql(P), on the other hand,
is obtained from <a href="#sqlite3_free">sqlite3_malloc()</a> and must be freed by the application
by passing it to <a href="#sqlite3_free">sqlite3_free()</a>.</p>
<p>The sqlite3_normalized_sql() interface is only available if
the <a href="compile.html#enable_normalize">SQLITE_ENABLE_NORMALIZE</a> compile-time option is defined.
</p><hr><a name="sqlite3_filename_database"></a>
<h2>Translate filenames</h2>
</div>
<blockquote><pre>
const char *sqlite3_filename_database(sqlite3_filename);
const char *sqlite3_filename_journal(sqlite3_filename);
const char *sqlite3_filename_wal(sqlite3_filename);
</pre></blockquote>
<p>
These routines are available to <a href="vfs.html">custom VFS implementations</a> for
translating filenames between the main database file, the journal file,
and the WAL file.</p>
<p>If F is the name of an sqlite database file, journal file, or WAL file
passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
returns the name of the corresponding database file.</p>
<p>If F is the name of an sqlite database file, journal file, or WAL file
passed by the SQLite core into the VFS, or if F is a database filename
obtained from <a href="#sqlite3_db_filename">sqlite3_db_filename()</a>, then sqlite3_filename_journal(F)
returns the name of the corresponding rollback journal file.</p>
<p>If F is the name of an sqlite database file, journal file, or WAL file
that was passed by the SQLite core into the VFS, or if F is a database
filename obtained from <a href="#sqlite3_db_filename">sqlite3_db_filename()</a>, then
sqlite3_filename_wal(F) returns the name of the corresponding
WAL file.</p>
<p>In all of the above, if F is not the name of a database, journal or WAL
filename passed into the VFS from the SQLite core and F is not the
return value from <a href="#sqlite3_db_filename">sqlite3_db_filename()</a>, then the result is
undefined and is likely a memory access violation.
</p><hr><a name="sqlite3_free"></a>
<h2>Memory Allocation Subsystem</h2>
</div>
<blockquote><pre>
void *sqlite3_malloc(int);
void *sqlite3_malloc64(sqlite3_uint64);
void *sqlite3_realloc(void*, int);
void *sqlite3_realloc64(void*, sqlite3_uint64);
void sqlite3_free(void*);
sqlite3_uint64 sqlite3_msize(void*);
</pre></blockquote>
<p>
The SQLite core uses these three routines for all of its own
internal memory allocation needs. "Core" in the previous sentence
does not include operating-system specific <a href="vfs.html">VFS</a> implementation. The
Windows VFS uses native malloc() and free() for some operations.</p>
<p>The sqlite3_malloc() routine returns a pointer to a block
of memory at least N bytes in length, where N is the parameter.
If sqlite3_malloc() is unable to obtain sufficient free
memory, it returns a NULL pointer. If the parameter N to
sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
a NULL pointer.</p>
<p>The sqlite3_malloc64(N) routine works just like
sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
of a signed 32-bit integer.</p>
<p>Calling sqlite3_free() with a pointer previously returned
by sqlite3_malloc() or sqlite3_realloc() releases that memory so
that it might be reused. The sqlite3_free() routine is
a no-op if is called with a NULL pointer. Passing a NULL pointer
to sqlite3_free() is harmless. After being freed, memory
should neither be read nor written. Even reading previously freed
memory might result in a segmentation fault or other severe error.
Memory corruption, a segmentation fault, or other severe error
might result if sqlite3_free() is called with a non-NULL pointer that
was not obtained from sqlite3_malloc() or sqlite3_realloc().</p>
<p>The sqlite3_realloc(X,N) interface attempts to resize a
prior memory allocation X to be at least N bytes.
If the X parameter to sqlite3_realloc(X,N)
is a NULL pointer then its behavior is identical to calling
sqlite3_malloc(N).
If the N parameter to sqlite3_realloc(X,N) is zero or
negative then the behavior is exactly the same as calling
sqlite3_free(X).
sqlite3_realloc(X,N) returns a pointer to a memory allocation
of at least N bytes in size or NULL if insufficient memory is available.
If M is the size of the prior allocation, then min(N,M) bytes
of the prior allocation are copied into the beginning of buffer returned
by sqlite3_realloc(X,N) and the prior allocation is freed.
If sqlite3_realloc(X,N) returns NULL and N is positive, then the
prior allocation is not freed.</p>
<p>The sqlite3_realloc64(X,N) interfaces works the same as
sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
of a 32-bit signed integer.</p>
<p>If X is a memory allocation previously obtained from sqlite3_malloc(),
sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
sqlite3_msize(X) returns the size of that memory allocation in bytes.
The value returned by sqlite3_msize(X) might be larger than the number
of bytes requested when X was allocated. If X is a NULL pointer then
sqlite3_msize(X) returns zero. If X points to something that is not
the beginning of memory allocation, or if it points to a formerly
valid memory allocation that has now been freed, then the behavior
of sqlite3_msize(X) is undefined and possibly harmful.</p>
<p>The memory returned by sqlite3_malloc(), sqlite3_realloc(),
sqlite3_malloc64(), and sqlite3_realloc64()
is always aligned to at least an 8 byte boundary, or to a
4 byte boundary if the <a href="compile.html#4_byte_aligned_malloc">SQLITE_4_BYTE_ALIGNED_MALLOC</a> compile-time
option is used.</p>
<p>The pointer arguments to <a href="#sqlite3_free">sqlite3_free()</a> and <a href="#sqlite3_free">sqlite3_realloc()</a>
must be either NULL or else pointers obtained from a prior
invocation of <a href="#sqlite3_free">sqlite3_malloc()</a> or <a href="#sqlite3_free">sqlite3_realloc()</a> that have
not yet been released.</p>
<p>The application must not read or write any part of
a block of memory after it has been released using
<a href="#sqlite3_free">sqlite3_free()</a> or <a href="#sqlite3_free">sqlite3_realloc()</a>.
</p><hr><a name="sqlite3_free_table"></a>
<h2>Convenience Routines For Running Queries</h2>
</div>
<blockquote><pre>
int sqlite3_get_table(
sqlite3 *db, /* An open database */
const char *zSql, /* SQL to be evaluated */
char ***pazResult, /* Results of the query */
int *pnRow, /* Number of result rows written here */
int *pnColumn, /* Number of result columns written here */
char **pzErrmsg /* Error msg written here */
);
void sqlite3_free_table(char **result);
</pre></blockquote>
<p>
This is a legacy interface that is preserved for backwards compatibility.
Use of this interface is not recommended.</p>
<p>Definition: A <b>result table</b> is memory data structure created by the
<a href="#sqlite3_free_table">sqlite3_get_table()</a> interface. A result table records the
complete query results from one or more queries.</p>
<p>The table conceptually has a number of rows and columns. But
these numbers are not part of the result table itself. These
numbers are obtained separately. Let N be the number of rows
and M be the number of columns.</p>
<p>A result table is an array of pointers to zero-terminated UTF-8 strings.
There are (N+1)*M elements in the array. The first M pointers point
to zero-terminated strings that contain the names of the columns.
The remaining entries all point to query results. NULL values result
in NULL pointers. All other values are in their UTF-8 zero-terminated
string representation as returned by <a href="#sqlite3_column_blob">sqlite3_column_text()</a>.</p>
<p>A result table might consist of one or more memory allocations.
It is not safe to pass a result table directly to <a href="#sqlite3_free">sqlite3_free()</a>.
A result table should be deallocated using <a href="#sqlite3_free_table">sqlite3_free_table()</a>.</p>
<p>As an example of the result table format, suppose a query result
is as follows:</p>
<p><blockquote><pre>
Name | Age
-----------------------
Alice | 43
Bob | 28
Cindy | 21
</pre></blockquote></p>
<p>There are two columns (M==2) and three rows (N==3). Thus the
result table has 8 entries. Suppose the result table is stored
in an array named azResult. Then azResult holds this content:</p>
<p><blockquote><pre>
azResult[0] = "Name";
azResult[1] = "Age";
azResult[2] = "Alice";
azResult[3] = "43";
azResult[4] = "Bob";
azResult[5] = "28";
azResult[6] = "Cindy";
azResult[7] = "21";
</pre></blockquote></p>
<p>The sqlite3_get_table() function evaluates one or more
semicolon-separated SQL statements in the zero-terminated UTF-8
string of its 2nd parameter and returns a result table to the
pointer given in its 3rd parameter.</p>
<p>After the application has finished with the result from sqlite3_get_table(),
it must pass the result table pointer to sqlite3_free_table() in order to
release the memory that was malloced. Because of the way the
<a href="#sqlite3_free">sqlite3_malloc()</a> happens within sqlite3_get_table(), the calling
function must not try to call <a href="#sqlite3_free">sqlite3_free()</a> directly. Only
<a href="#sqlite3_free_table">sqlite3_free_table()</a> is able to release the memory properly and safely.</p>
<p>The sqlite3_get_table() interface is implemented as a wrapper around
<a href="#sqlite3_exec">sqlite3_exec()</a>. The sqlite3_get_table() routine does not have access
to any internal data structures of SQLite. It uses only the public
interface defined here. As a consequence, errors that occur in the
wrapper layer outside of the internal <a href="#sqlite3_exec">sqlite3_exec()</a> call are not
reflected in subsequent calls to <a href="#sqlite3_errcode">sqlite3_errcode()</a> or
<a href="#sqlite3_errcode">sqlite3_errmsg()</a>.
</p><hr><a name="sqlite3_get_auxdata"></a>
<h2>Function Auxiliary Data</h2>
</div>
<blockquote><pre>
void *sqlite3_get_auxdata(sqlite3_context*, int N);
void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
</pre></blockquote>
<p>
These functions may be used by (non-aggregate) SQL functions to
associate auxiliary data with argument values. If the same argument
value is passed to multiple invocations of the same SQL function during
query execution, under some circumstances the associated auxiliary data
might be preserved. An example of where this might be useful is in a
regular-expression matching function. The compiled version of the regular
expression can be stored as auxiliary data associated with the pattern string.
Then as long as the pattern string remains the same,
the compiled regular expression can be reused on multiple
invocations of the same function.</p>
<p>The sqlite3_get_auxdata(C,N) interface returns a pointer to the auxiliary data
associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
value to the application-defined function. N is zero for the left-most
function argument. If there is no auxiliary data
associated with the function argument, the sqlite3_get_auxdata(C,N) interface
returns a NULL pointer.</p>
<p>The sqlite3_set_auxdata(C,N,P,X) interface saves P as auxiliary data for the
N-th argument of the application-defined function. Subsequent
calls to sqlite3_get_auxdata(C,N) return P from the most recent
sqlite3_set_auxdata(C,N,P,X) call if the auxiliary data is still valid or
NULL if the auxiliary data has been discarded.
After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
SQLite will invoke the destructor function X with parameter P exactly
once, when the auxiliary data is discarded.
SQLite is free to discard the auxiliary data at any time, including: <ul>
<li> when the corresponding function parameter changes, or
<li> when <a href="#sqlite3_reset">sqlite3_reset()</a> or <a href="#sqlite3_finalize">sqlite3_finalize()</a> is called for the
SQL statement, or
<li> when sqlite3_set_auxdata() is invoked again on the same
parameter, or
<li> during the original sqlite3_set_auxdata() call when a memory
allocation error occurs.
<li> during the original sqlite3_set_auxdata() call if the function
is evaluated during query planning instead of during query execution,
as sometimes happens with <a href="compile.html#enable_stat4">SQLITE_ENABLE_STAT4</a>. </ul></p>
<p>Note the last two bullets in particular. The destructor X in
sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
should be called near the end of the function implementation and the
function implementation should not make any use of P after
sqlite3_set_auxdata() has been called. Furthermore, a call to
sqlite3_get_auxdata() that occurs immediately after a corresponding call
to sqlite3_set_auxdata() might still return NULL if an out-of-memory
condition occurred during the sqlite3_set_auxdata() call or if the
function is being evaluated during query planning rather than during
query execution.</p>
<p>In practice, auxiliary data is preserved between function calls for
function parameters that are compile-time constants, including literal
values and <a href="lang_expr.html#varparam">parameters</a> and expressions composed from the same.</p>
<p>The value of the N parameter to these interfaces should be non-negative.
Future enhancements may make use of negative N values to define new
kinds of function caching behavior.</p>
<p>These routines must be called from the same thread in which
the SQL function is running.</p>
<p>See also: <a href="#sqlite3_get_clientdata">sqlite3_get_clientdata()</a> and <a href="#sqlite3_get_clientdata">sqlite3_set_clientdata()</a>.
</p><hr><a name="sqlite3_get_clientdata"></a>
<h2>Database Connection Client Data</h2>
</div>
<blockquote><pre>
void *sqlite3_get_clientdata(sqlite3*,const char*);
int sqlite3_set_clientdata(sqlite3*, const char*, void*, void(*)(void*));
</pre></blockquote>
<p>
These functions are used to associate one or more named pointers
with a <a href="#sqlite3">database connection</a>.
A call to sqlite3_set_clientdata(D,N,P,X) causes the pointer P
to be attached to <a href="#sqlite3">database connection</a> D using name N. Subsequent
calls to sqlite3_get_clientdata(D,N) will return a copy of pointer P
or a NULL pointer if there were no prior calls to
sqlite3_set_clientdata() with the same values of D and N.
Names are compared using strcmp() and are thus case sensitive.</p>
<p>If P and X are both non-NULL, then the destructor X is invoked with
argument P on the first of the following occurrences:
<ul>
<li> An out-of-memory error occurs during the call to
sqlite3_set_clientdata() which attempts to register pointer P.
<li> A subsequent call to sqlite3_set_clientdata(D,N,P,X) is made
with the same D and N parameters.
<li> The database connection closes. SQLite does not make any guarantees
about the order in which destructors are called, only that all
destructors will be called exactly once at some point during the
database connection closing process.
</ul></p>
<p>SQLite does not do anything with client data other than invoke
destructors on the client data at the appropriate time. The intended
use for client data is to provide a mechanism for wrapper libraries
to store additional information about an SQLite database connection.</p>
<p>There is no limit (other than available memory) on the number of different
client data pointers (with different names) that can be attached to a
single database connection. However, the implementation is optimized
for the case of having only one or two different client data names.
Applications and wrapper libraries are discouraged from using more than
one client data name each.</p>
<p>There is no way to enumerate the client data pointers
associated with a database connection. The N parameter can be thought
of as a secret key such that only code that knows the secret key is able
to access the associated data.</p>
<p>Security Warning: These interfaces should not be exposed in scripting
languages or in other circumstances where it might be possible for an
an attacker to invoke them. Any agent that can invoke these interfaces
can probably also take control of the process.</p>
<p>Database connection client data is only available for SQLite
version 3.44.0 (2023-11-01) and later.</p>
<p>See also: <a href="#sqlite3_get_auxdata">sqlite3_set_auxdata()</a> and <a href="#sqlite3_get_auxdata">sqlite3_get_auxdata()</a>.
</p><hr><a name="sqlite3_hard_heap_limit64"></a>
<h2>Impose A Limit On Heap Size</h2>
</div>
<blockquote><pre>
sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
</pre></blockquote>
<p>
These interfaces impose limits on the amount of heap memory that will be
by all database connections within a single process.</p>
<p>The sqlite3_soft_heap_limit64() interface sets and/or queries the
soft limit on the amount of heap memory that may be allocated by SQLite.
SQLite strives to keep heap memory utilization below the soft heap
limit by reducing the number of pages held in the page cache
as heap memory usages approaches the limit.
The soft heap limit is "soft" because even though SQLite strives to stay
below the limit, it will exceed the limit rather than generate
an <a href="#SQLITE_ABORT">SQLITE_NOMEM</a> error. In other words, the soft heap limit
is advisory only.</p>
<p>The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
N bytes on the amount of memory that will be allocated. The
sqlite3_hard_heap_limit64(N) interface is similar to
sqlite3_soft_heap_limit64(N) except that memory allocations will fail
when the hard heap limit is reached.</p>
<p>The return value from both sqlite3_soft_heap_limit64() and
sqlite3_hard_heap_limit64() is the size of
the heap limit prior to the call, or negative in the case of an
error. If the argument N is negative
then no change is made to the heap limit. Hence, the current
size of heap limits can be determined by invoking
sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).</p>
<p>Setting the heap limits to zero disables the heap limiter mechanism.</p>
<p>The soft heap limit may not be greater than the hard heap limit.
If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
is invoked with a value of N that is greater than the hard heap limit,
the soft heap limit is set to the value of the hard heap limit.
The soft heap limit is automatically enabled whenever the hard heap
limit is enabled. When sqlite3_hard_heap_limit64(N) is invoked and
the soft heap limit is outside the range of 1..N, then the soft heap
limit is set to N. Invoking sqlite3_soft_heap_limit64(0) when the
hard heap limit is enabled makes the soft heap limit equal to the
hard heap limit.</p>
<p>The memory allocation limits can also be adjusted using
<a href="pragma.html#pragma_soft_heap_limit">PRAGMA soft_heap_limit</a> and <a href="pragma.html#pragma_hard_heap_limit">PRAGMA hard_heap_limit</a>.</p>
<p>The heap limits are not enforced in the current implementation
if one or more of following conditions are true:</p>
<p><ul>
<li> The limit value is set to zero.
<li> Memory accounting is disabled using a combination of the
<a href="#sqlite3_config">sqlite3_config</a>(<a href="#sqliteconfigmemstatus">SQLITE_CONFIG_MEMSTATUS</a>,...) start-time option and
the <a href="compile.html#default_memstatus">SQLITE_DEFAULT_MEMSTATUS</a> compile-time option.
<li> An alternative page cache implementation is specified using
<a href="#sqlite3_config">sqlite3_config</a>(<a href="#sqliteconfigpcache2">SQLITE_CONFIG_PCACHE2</a>,...).
<li> The page cache allocates from its own memory pool supplied
by <a href="#sqlite3_config">sqlite3_config</a>(<a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>,...) rather than
from the heap.
</ul></p>
<p>The circumstances under which SQLite will enforce the heap limits may
changes in future releases of SQLite.
</p><hr><a name="sqlite3_initialize"></a>
<h2>Initialize The SQLite Library</h2>
</div>
<blockquote><pre>
int sqlite3_initialize(void);
int sqlite3_shutdown(void);
int sqlite3_os_init(void);
int sqlite3_os_end(void);
</pre></blockquote>
<p>
The sqlite3_initialize() routine initializes the
SQLite library. The sqlite3_shutdown() routine
deallocates any resources that were allocated by sqlite3_initialize().
These routines are designed to aid in process initialization and
shutdown on embedded systems. Workstation applications using
SQLite normally do not need to invoke either of these routines.</p>
<p>A call to sqlite3_initialize() is an "effective" call if it is
the first time sqlite3_initialize() is invoked during the lifetime of
the process, or if it is the first time sqlite3_initialize() is invoked
following a call to sqlite3_shutdown(). Only an effective call
of sqlite3_initialize() does any initialization. All other calls
are harmless no-ops.</p>
<p>A call to sqlite3_shutdown() is an "effective" call if it is the first
call to sqlite3_shutdown() since the last sqlite3_initialize(). Only
an effective call to sqlite3_shutdown() does any deinitialization.
All other valid calls to sqlite3_shutdown() are harmless no-ops.</p>
<p>The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
is not. The sqlite3_shutdown() interface must only be called from a
single thread. All open <a href="#sqlite3">database connections</a> must be closed and all
other SQLite resources must be deallocated prior to invoking
sqlite3_shutdown().</p>
<p>Among other things, sqlite3_initialize() will invoke
sqlite3_os_init(). Similarly, sqlite3_shutdown()
will invoke sqlite3_os_end().</p>
<p>The sqlite3_initialize() routine returns <a href="#SQLITE_ABORT">SQLITE_OK</a> on success.
If for some reason, sqlite3_initialize() is unable to initialize
the library (perhaps it is unable to allocate a needed resource such
as a mutex) it returns an <a href="rescode.html">error code</a> other than <a href="#SQLITE_ABORT">SQLITE_OK</a>.</p>
<p>The sqlite3_initialize() routine is called internally by many other
SQLite interfaces so that an application usually does not need to
invoke sqlite3_initialize() directly. For example, <a href="#sqlite3_open">sqlite3_open()</a>
calls sqlite3_initialize() so the SQLite library will be automatically
initialized when <a href="#sqlite3_open">sqlite3_open()</a> is called if it has not be initialized
already. However, if SQLite is compiled with the <a href="compile.html#omit_autoinit">SQLITE_OMIT_AUTOINIT</a>
compile-time option, then the automatic calls to sqlite3_initialize()
are omitted and the application must call sqlite3_initialize() directly
prior to using any other SQLite interface. For maximum portability,
it is recommended that applications always invoke sqlite3_initialize()
directly prior to using any other SQLite interface. Future releases
of SQLite may require this. In other words, the behavior exhibited
when SQLite is compiled with <a href="compile.html#omit_autoinit">SQLITE_OMIT_AUTOINIT</a> might become the
default behavior in some future release of SQLite.</p>
<p>The sqlite3_os_init() routine does operating-system specific
initialization of the SQLite library. The sqlite3_os_end()
routine undoes the effect of sqlite3_os_init(). Typical tasks
performed by these routines include allocation or deallocation
of static resources, initialization of global variables,
setting up a default <a href="#sqlite3_vfs">sqlite3_vfs</a> module, or setting up
a default configuration using <a href="#sqlite3_config">sqlite3_config()</a>.</p>
<p>The application should never invoke either sqlite3_os_init()
or sqlite3_os_end() directly. The application should only invoke
sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
interface is called automatically by sqlite3_initialize() and
sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
implementations for sqlite3_os_init() and sqlite3_os_end()
are built into SQLite when it is compiled for Unix, Windows, or OS/2.
When <a href="custombuild.html">built for other platforms</a>
(using the <a href="compile.html#os_other">SQLITE_OS_OTHER=1</a> compile-time
option) the application must supply a suitable implementation for
sqlite3_os_init() and sqlite3_os_end(). An application-supplied
implementation of sqlite3_os_init() or sqlite3_os_end()
must return <a href="#SQLITE_ABORT">SQLITE_OK</a> on success and some other <a href="rescode.html">error code</a> upon
failure.
</p><hr><a name="sqlite3_interrupt"></a>
<h2>Interrupt A Long-Running Query</h2>
</div>
<blockquote><pre>
void sqlite3_interrupt(sqlite3*);
int sqlite3_is_interrupted(sqlite3*);
</pre></blockquote>
<p>
This function causes any pending database operation to abort and
return at its earliest opportunity. This routine is typically
called in response to a user action such as pressing "Cancel"
or Ctrl-C where the user wants a long query operation to halt
immediately.</p>
<p>It is safe to call this routine from a thread different from the
thread that is currently running the database operation. But it
is not safe to call this routine with a <a href="#sqlite3">database connection</a> that
is closed or might close before sqlite3_interrupt() returns.</p>
<p>If an SQL operation is very nearly finished at the time when
sqlite3_interrupt() is called, then it might not have an opportunity
to be interrupted and might continue to completion.</p>
<p>An SQL operation that is interrupted will return <a href="#SQLITE_ABORT">SQLITE_INTERRUPT</a>.
If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
that is inside an explicit transaction, then the entire transaction
will be rolled back automatically.</p>
<p>The sqlite3_interrupt(D) call is in effect until all currently running
SQL statements on <a href="#sqlite3">database connection</a> D complete. Any new SQL statements
that are started after the sqlite3_interrupt() call and before the
running statement count reaches zero are interrupted as if they had been
running prior to the sqlite3_interrupt() call. New SQL statements
that are started after the running statement count reaches zero are
not effected by the sqlite3_interrupt().
A call to sqlite3_interrupt(D) that occurs when there are no running
SQL statements is a no-op and has no effect on SQL statements
that are started after the sqlite3_interrupt() call returns.</p>
<p>The <a href="#sqlite3_interrupt">sqlite3_is_interrupted(D)</a> interface can be used to determine whether
or not an interrupt is currently in effect for <a href="#sqlite3">database connection</a> D.
It returns 1 if an interrupt is currently in effect, or 0 otherwise.
</p><hr><a name="sqlite3_keyword_check"></a>
<h2>SQL Keyword Checking</h2>
</div>
<blockquote><pre>
int sqlite3_keyword_count(void);
int sqlite3_keyword_name(int,const char**,int*);
int sqlite3_keyword_check(const char*,int);
</pre></blockquote>
<p>
These routines provide access to the set of SQL language keywords
recognized by SQLite. Applications can uses these routines to determine
whether or not a specific identifier needs to be escaped (for example,
by enclosing in double-quotes) so as not to confuse the parser.</p>
<p>The sqlite3_keyword_count() interface returns the number of distinct
keywords understood by SQLite.</p>
<p>The sqlite3_keyword_name(N,Z,L) interface finds the 0-based N-th keyword and
makes *Z point to that keyword expressed as UTF8 and writes the number
of bytes in the keyword into *L. The string that *Z points to is not
zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns
SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
or L are NULL or invalid pointers then calls to
sqlite3_keyword_name(N,Z,L) result in undefined behavior.</p>
<p>The sqlite3_keyword_check(Z,L) interface checks to see whether or not
the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
if it is and zero if not.</p>
<p>The parser used by SQLite is forgiving. It is often possible to use
a keyword as an identifier as long as such use does not result in a
parsing ambiguity. For example, the statement
"CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
creates a new table named "BEGIN" with three columns named
"REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid
using keywords as identifiers. Common techniques used to avoid keyword
name collisions include:
<ul>
<li> Put all identifier names inside double-quotes. This is the official
SQL way to escape identifier names.
<li> Put identifier names inside [...]. This is not standard SQL,
but it is what SQL Server does and so lots of programmers use this
technique.
<li> Begin every identifier with the letter "Z" as no SQL keywords start
with "Z".
<li> Include a digit somewhere in every identifier name.
</ul></p>
<p>Note that the number of keywords understood by SQLite can depend on
compile-time options. For example, "VACUUM" is not a keyword if
SQLite is compiled with the <a href="compile.html#omit_vacuum">-DSQLITE_OMIT_VACUUM</a> option. Also,
new keywords may be added to future releases of SQLite.
</p><hr><a name="sqlite3_libversion"></a>
<h2>Run-Time Library Version Numbers</h2>
</div>
<blockquote><pre>
SQLITE_EXTERN const char sqlite3_version[];
const char *sqlite3_libversion(void);
const char *sqlite3_sourceid(void);
int sqlite3_libversion_number(void);
</pre></blockquote>
<p>
These interfaces provide the same information as the <a href="#SQLITE_SOURCE_ID">SQLITE_VERSION</a>,
<a href="#SQLITE_SOURCE_ID">SQLITE_VERSION_NUMBER</a>, and <a href="#SQLITE_SOURCE_ID">SQLITE_SOURCE_ID</a> C preprocessor macros
but are associated with the library instead of the header file. Cautious
programmers might include assert() statements in their application to
verify that values returned by these interfaces match the macros in
the header, and thus ensure that the application is
compiled with matching library and header files.</p>
<p><blockquote><pre>
assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
</pre></blockquote></p>
<p>The sqlite3_version[] string constant contains the text of <a href="#SQLITE_SOURCE_ID">SQLITE_VERSION</a>
macro. The sqlite3_libversion() function returns a pointer to the
to the sqlite3_version[] string constant. The sqlite3_libversion()
function is provided for use in DLLs since DLL users usually do not have
direct access to string constants within the DLL. The
sqlite3_libversion_number() function returns an integer equal to
<a href="#SQLITE_SOURCE_ID">SQLITE_VERSION_NUMBER</a>. The sqlite3_sourceid() function returns
a pointer to a string constant whose value is the same as the
<a href="#SQLITE_SOURCE_ID">SQLITE_SOURCE_ID</a> C preprocessor macro. Except if SQLite is built
using an edited copy of <a href="amalgamation.html">the amalgamation</a>, then the last four characters
of the hash might be different from <a href="#SQLITE_SOURCE_ID">SQLITE_SOURCE_ID</a>.</p>
<p>See also: <a href="lang_corefunc.html#sqlite_version">sqlite_version()</a> and <a href="lang_corefunc.html#sqlite_source_id">sqlite_source_id()</a>.
</p><hr><a name="sqlite3_memory_highwater"></a>
<h2>Memory Allocator Statistics</h2>
</div>
<blockquote><pre>
sqlite3_int64 sqlite3_memory_used(void);
sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
</pre></blockquote>
<p>
SQLite provides these two interfaces for reporting on the status
of the <a href="#sqlite3_free">sqlite3_malloc()</a>, <a href="#sqlite3_free">sqlite3_free()</a>, and <a href="#sqlite3_free">sqlite3_realloc()</a>
routines, which form the built-in memory allocation subsystem.</p>
<p>The <a href="#sqlite3_memory_highwater">sqlite3_memory_used()</a> routine returns the number of bytes
of memory currently outstanding (malloced but not freed).
The <a href="#sqlite3_memory_highwater">sqlite3_memory_highwater()</a> routine returns the maximum
value of <a href="#sqlite3_memory_highwater">sqlite3_memory_used()</a> since the high-water mark
was last reset. The values returned by <a href="#sqlite3_memory_highwater">sqlite3_memory_used()</a> and
<a href="#sqlite3_memory_highwater">sqlite3_memory_highwater()</a> include any overhead
added by SQLite in its implementation of <a href="#sqlite3_free">sqlite3_malloc()</a>,
but not overhead added by the any underlying system library
routines that <a href="#sqlite3_free">sqlite3_malloc()</a> may call.</p>
<p>The memory high-water mark is reset to the current value of
<a href="#sqlite3_memory_highwater">sqlite3_memory_used()</a> if and only if the parameter to
<a href="#sqlite3_memory_highwater">sqlite3_memory_highwater()</a> is true. The value returned
by <a href="#sqlite3_memory_highwater">sqlite3_memory_highwater(1)</a> is the high-water mark
prior to the reset.
</p><hr><a name="sqlite3_mprintf"></a>
<h2>Formatted String Printing Functions</h2>
</div>
<blockquote><pre>
char *sqlite3_mprintf(const char*,...);
char *sqlite3_vmprintf(const char*, va_list);
char *sqlite3_snprintf(int,char*,const char*, ...);
char *sqlite3_vsnprintf(int,char*,const char*, va_list);
</pre></blockquote>
<p>
These routines are work-alikes of the "printf()" family of functions
from the standard C library.
These routines understand most of the common formatting options from
the standard library printf()
plus some additional non-standard formats (<a href="printf.html#percentq">%q</a>, <a href="printf.html#percentq">%Q</a>, <a href="printf.html#percentw">%w</a>, and <a href="printf.html#percentz">%z</a>).
See the <a href="printf.html">built-in printf()</a> documentation for details.</p>
<p>The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
results into memory obtained from <a href="#sqlite3_free">sqlite3_malloc64()</a>.
The strings returned by these two routines should be
released by <a href="#sqlite3_free">sqlite3_free()</a>. Both routines return a
NULL pointer if <a href="#sqlite3_free">sqlite3_malloc64()</a> is unable to allocate enough
memory to hold the resulting string.</p>
<p>The sqlite3_snprintf() routine is similar to "snprintf()" from
the standard C library. The result is written into the
buffer supplied as the second parameter whose size is given by
the first parameter. Note that the order of the
first two parameters is reversed from snprintf(). This is an
historical accident that cannot be fixed without breaking
backwards compatibility. Note also that sqlite3_snprintf()
returns a pointer to its buffer instead of the number of
characters actually written into the buffer. We admit that
the number of characters written would be a more useful return
value but we cannot change the implementation of sqlite3_snprintf()
now without breaking compatibility.</p>
<p>As long as the buffer size is greater than zero, sqlite3_snprintf()
guarantees that the buffer is always zero-terminated. The first
parameter "n" is the total size of the buffer, including space for
the zero terminator. So the longest string that can be completely
written will be n-1 characters.</p>
<p>The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().</p>
<p>See also: <a href="printf.html">built-in printf()</a>, <a href="lang_corefunc.html#printf">printf() SQL function</a>
</p><hr><a name="sqlite3_mutex_alloc"></a>
<h2>Mutexes</h2>
</div>
<blockquote><pre>
sqlite3_mutex *sqlite3_mutex_alloc(int);
void sqlite3_mutex_free(sqlite3_mutex*);
void sqlite3_mutex_enter(sqlite3_mutex*);
int sqlite3_mutex_try(sqlite3_mutex*);
void sqlite3_mutex_leave(sqlite3_mutex*);
</pre></blockquote>
<p>
The SQLite core uses these routines for thread
synchronization. Though they are intended for internal
use by SQLite, code that links against SQLite is
permitted to use any of these routines.</p>
<p>The SQLite source code contains multiple implementations
of these mutex routines. An appropriate implementation
is selected automatically at compile-time. The following
implementations are available in the SQLite core:</p>
<p><ul>
<li> SQLITE_MUTEX_PTHREADS
<li> SQLITE_MUTEX_W32
<li> SQLITE_MUTEX_NOOP
</ul></p>
<p>The SQLITE_MUTEX_NOOP implementation is a set of routines
that does no real locking and is appropriate for use in
a single-threaded application. The SQLITE_MUTEX_PTHREADS and
SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
and Windows.</p>
<p>If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
implementation is included with the library. In this case the
application must supply a custom mutex implementation using the
<a href="#sqliteconfigmutex">SQLITE_CONFIG_MUTEX</a> option of the sqlite3_config() function
before calling sqlite3_initialize() or any other public sqlite3_
function that calls sqlite3_initialize().</p>
<p>The sqlite3_mutex_alloc() routine allocates a new
mutex and returns a pointer to it. The sqlite3_mutex_alloc()
routine returns NULL if it is unable to allocate the requested
mutex. The argument to sqlite3_mutex_alloc() must one of these
integer constants:</p>
<p><ul>
<li> SQLITE_MUTEX_FAST
<li> SQLITE_MUTEX_RECURSIVE
<li> SQLITE_MUTEX_STATIC_MAIN
<li> SQLITE_MUTEX_STATIC_MEM
<li> SQLITE_MUTEX_STATIC_OPEN
<li> SQLITE_MUTEX_STATIC_PRNG
<li> SQLITE_MUTEX_STATIC_LRU
<li> SQLITE_MUTEX_STATIC_PMEM
<li> SQLITE_MUTEX_STATIC_APP1
<li> SQLITE_MUTEX_STATIC_APP2
<li> SQLITE_MUTEX_STATIC_APP3
<li> SQLITE_MUTEX_STATIC_VFS1
<li> SQLITE_MUTEX_STATIC_VFS2
<li> SQLITE_MUTEX_STATIC_VFS3
</ul></p>
<p>The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
cause sqlite3_mutex_alloc() to create
a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
is used but not necessarily so when SQLITE_MUTEX_FAST is used.
The mutex implementation does not need to make a distinction
between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
not want to. SQLite will only request a recursive mutex in
cases where it really needs one. If a faster non-recursive mutex
implementation is available on the host platform, the mutex subsystem
might return such a mutex in response to SQLITE_MUTEX_FAST.</p>
<p>The other allowed parameters to sqlite3_mutex_alloc() (anything other
than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
a pointer to a static preexisting mutex. Nine static mutexes are
used by the current version of SQLite. Future versions of SQLite
may add additional static mutexes. Static mutexes are for internal
use by SQLite only. Applications that use SQLite mutexes should
use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
SQLITE_MUTEX_RECURSIVE.</p>
<p>Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
returns a different mutex on every call. For the static
mutex types, the same mutex is returned on every call that has
the same type number.</p>
<p>The sqlite3_mutex_free() routine deallocates a previously
allocated dynamic mutex. Attempting to deallocate a static
mutex results in undefined behavior.</p>
<p>The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
to enter a mutex. If another thread is already within the mutex,
sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
SQLITE_BUSY. The sqlite3_mutex_try() interface returns <a href="#SQLITE_ABORT">SQLITE_OK</a>
upon successful entry. Mutexes created using
SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
In such cases, the
mutex must be exited an equal number of times before another thread
can enter. If the same thread tries to enter any mutex other
than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.</p>
<p>Some systems (for example, Windows 95) do not support the operation
implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
will always return SQLITE_BUSY. In most cases the SQLite core only uses
sqlite3_mutex_try() as an optimization, so this is acceptable
behavior. The exceptions are unix builds that set the
SQLITE_ENABLE_SETLK_TIMEOUT build option. In that case a working
sqlite3_mutex_try() is required.</p>
<p>The sqlite3_mutex_leave() routine exits a mutex that was
previously entered by the same thread. The behavior
is undefined if the mutex is not currently entered by the
calling thread or is not currently allocated.</p>
<p>If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(),
sqlite3_mutex_leave(), or sqlite3_mutex_free() is a NULL pointer,
then any of the four routines behaves as a no-op.</p>
<p>See also: <a href="#sqlite3_mutex_held">sqlite3_mutex_held()</a> and <a href="#sqlite3_mutex_held">sqlite3_mutex_notheld()</a>.
</p><hr><a name="sqlite3_mutex_held"></a>
<h2>Mutex Verification Routines</h2>
</div>
<blockquote><pre>
#ifndef NDEBUG
int sqlite3_mutex_held(sqlite3_mutex*);
int sqlite3_mutex_notheld(sqlite3_mutex*);
#endif
</pre></blockquote>
<p>
The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
are intended for use inside assert() statements. The SQLite core
never uses these routines except inside an assert() and applications
are advised to follow the lead of the core. The SQLite core only
provides implementations for these routines when it is compiled
with the SQLITE_DEBUG flag. External mutex implementations
are only required to provide these routines if SQLITE_DEBUG is
defined and if NDEBUG is not defined.</p>
<p>These routines should return true if the mutex in their argument
is held or not held, respectively, by the calling thread.</p>
<p>The implementation is not required to provide versions of these
routines that actually work. If the implementation does not provide working
versions of these routines, it should at least provide stubs that always
return true so that one does not get spurious assertion failures.</p>
<p>If the argument to sqlite3_mutex_held() is a NULL pointer then
the routine should return 1. This seems counter-intuitive since
clearly the mutex cannot be held if it does not exist. But
the reason the mutex does not exist is because the build is not
using mutexes. And we do not want the assert() containing the
call to sqlite3_mutex_held() to fail, so a non-zero return is
the appropriate thing to do. The sqlite3_mutex_notheld()
interface should also return 1 when given a NULL pointer.
</p><hr><a name="sqlite3_open"></a>
<h2>Opening A New Database Connection</h2>
</div>
<blockquote><pre>
int sqlite3_open(
const char *filename, /* Database filename (UTF-8) */
sqlite3 **ppDb /* OUT: SQLite db handle */
);
int sqlite3_open16(
const void *filename, /* Database filename (UTF-16) */
sqlite3 **ppDb /* OUT: SQLite db handle */
);
int sqlite3_open_v2(
const char *filename, /* Database filename (UTF-8) */
sqlite3 **ppDb, /* OUT: SQLite db handle */
int flags, /* Flags */
const char *zVfs /* Name of VFS module to use */
);
</pre></blockquote>
<p>
These routines open an SQLite database file as specified by the
filename argument. The filename argument is interpreted as UTF-8 for
sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
order for sqlite3_open16(). A <a href="#sqlite3">database connection</a> handle is usually
returned in *ppDb, even if an error occurs. The only exception is that
if SQLite is unable to allocate memory to hold the <a href="#sqlite3">sqlite3</a> object,
a NULL will be written into *ppDb instead of a pointer to the <a href="#sqlite3">sqlite3</a>
object. If the database is opened (and/or created) successfully, then
<a href="#SQLITE_ABORT">SQLITE_OK</a> is returned. Otherwise an <a href="rescode.html">error code</a> is returned. The
<a href="#sqlite3_errcode">sqlite3_errmsg()</a> or <a href="#sqlite3_errcode">sqlite3_errmsg16()</a> routines can be used to obtain
an English language description of the error following a failure of any
of the sqlite3_open() routines.</p>
<p>The default encoding will be UTF-8 for databases created using
sqlite3_open() or sqlite3_open_v2(). The default encoding for databases
created using sqlite3_open16() will be UTF-16 in the native byte order.</p>
<p>Whether or not an error occurs when it is opened, resources
associated with the <a href="#sqlite3">database connection</a> handle should be released by
passing it to <a href="#sqlite3_close">sqlite3_close()</a> when it is no longer required.</p>
<p>The sqlite3_open_v2() interface works like sqlite3_open()
except that it accepts two additional parameters for additional control
over the new database connection. The flags parameter to
sqlite3_open_v2() must include, at a minimum, one of the following
three flag combinations:</p>
<p><dl>
<dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READONLY</a></dt>
<dd>The database is opened in read-only mode. If the database does
not already exist, an error is returned.</dd></p>
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READWRITE</a></dt>
<dd>The database is opened for reading and writing if possible, or
reading only if the file is write protected by the operating
system. In either case the database must already exist, otherwise
an error is returned. For historical reasons, if opening in
read-write mode fails due to OS-level permissions, an attempt is
made to open it in read-only mode. <a href="#sqlite3_db_readonly">sqlite3_db_readonly()</a> can be
used to determine whether the database is actually
read-write.</dd></p>
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READWRITE</a> | <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_CREATE</a></dt>
<dd>The database is opened for reading and writing, and is created if
it does not already exist. This is the behavior that is always used for
sqlite3_open() and sqlite3_open16().</dd>
</dl></p>
<p>In addition to the required flags, the following optional flags are
also supported:</p>
<p><dl>
<dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_URI</a></dt>
<dd>The filename can be interpreted as a URI if this flag is set.</dd></p>
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_MEMORY</a></dt>
<dd>The database will be opened as an in-memory database. The database
is named by the "filename" argument for the purposes of cache-sharing,
if shared cache mode is enabled, but the "filename" is otherwise ignored.
</dd></p>
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_NOMUTEX</a></dt>
<dd>The new database connection will use the "multi-thread"
<a href="threadsafe.html">threading mode</a>. This means that separate threads are allowed
to use SQLite at the same time, as long as each thread is using
a different <a href="#sqlite3">database connection</a>.</p>
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_FULLMUTEX</a></dt>
<dd>The new database connection will use the "serialized"
<a href="threadsafe.html">threading mode</a>. This means the multiple threads can safely
attempt to use the same database connection at the same time.
(Mutexes will block any actual concurrency, but in this mode
there is no harm in trying.)</p>
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_SHAREDCACHE</a></dt>
<dd>The database is opened <a href="sharedcache.html">shared cache</a> enabled, overriding
the default shared cache setting provided by
<a href="#sqlite3_enable_shared_cache">sqlite3_enable_shared_cache()</a>.
The <a href="sharedcache.html#dontuse">use of shared cache mode is discouraged</a> and hence shared cache
capabilities may be omitted from many builds of SQLite. In such cases,
this option is a no-op.</p>
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_PRIVATECACHE</a></dt>
<dd>The database is opened <a href="sharedcache.html">shared cache</a> disabled, overriding
the default shared cache setting provided by
<a href="#sqlite3_enable_shared_cache">sqlite3_enable_shared_cache()</a>.</p>
<p><a name="openexrescode"></a>
<dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_EXRESCODE</a></dt>
<dd>The database connection comes up in "extended result code mode".
In other words, the database behaves has if
<a href="#sqlite3_extended_result_codes">sqlite3_extended_result_codes(db,1)</a> where called on the database
connection as soon as the connection is created. In addition to setting
the extended result code mode, this flag also causes <a href="#sqlite3_open">sqlite3_open_v2()</a>
to return an extended result code.</dd></p>
<p><a name="opennofollow"></a>
<dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_NOFOLLOW</a></dt>
<dd>The database filename is not allowed to contain a symbolic link</dd>
</dl></p>
<p>If the 3rd parameter to sqlite3_open_v2() is not one of the
required combinations shown above optionally combined with other
<a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_* bits</a>
then the behavior is undefined. Historic versions of SQLite
have silently ignored surplus bits in the flags parameter to
sqlite3_open_v2(), however that behavior might not be carried through
into future versions of SQLite and so applications should not rely
upon it. Note in particular that the SQLITE_OPEN_EXCLUSIVE flag is a no-op
for sqlite3_open_v2(). The SQLITE_OPEN_EXCLUSIVE does *not* cause
the open to fail if the database already exists. The SQLITE_OPEN_EXCLUSIVE
flag is intended for use by the <a href="#sqlite3_vfs">VFS interface</a> only, and not
by sqlite3_open_v2().</p>
<p>The fourth parameter to sqlite3_open_v2() is the name of the
<a href="#sqlite3_vfs">sqlite3_vfs</a> object that defines the operating system interface that
the new database connection should use. If the fourth parameter is
a NULL pointer then the default <a href="#sqlite3_vfs">sqlite3_vfs</a> object is used.</p>
<p>If the filename is ":memory:", then a private, temporary in-memory database
is created for the connection. This in-memory database will vanish when
the database connection is closed. Future versions of SQLite might
make use of additional special filenames that begin with the ":" character.
It is recommended that when a database filename actually does begin with
a ":" character you should prefix the filename with a pathname such as
"./" to avoid ambiguity.</p>
<p>If the filename is an empty string, then a private, temporary
on-disk database will be created. This private database will be
automatically deleted as soon as the database connection is closed.</p>
<p><a name="urifilenamesinsqlite3open"></a>
<h3>URI Filenames</h3></p>
<p>If <a href="uri.html">URI filename</a> interpretation is enabled, and the filename argument
begins with "file:", then the filename is interpreted as a URI. URI
filename interpretation is enabled if the <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_URI</a> flag is
set in the third argument to sqlite3_open_v2(), or if it has
been enabled globally using the <a href="#sqliteconfiguri">SQLITE_CONFIG_URI</a> option with the
<a href="#sqlite3_config">sqlite3_config()</a> method or by the <a href="compile.html#use_uri">SQLITE_USE_URI</a> compile-time option.
URI filename interpretation is turned off
by default, but future releases of SQLite might enable URI filename
interpretation by default. See "<a href="uri.html">URI filenames</a>" for additional
information.</p>
<p>URI filenames are parsed according to RFC 3986. If the URI contains an
authority, then it must be either an empty string or the string
"localhost". If the authority is not an empty string or "localhost", an
error is returned to the caller. The fragment component of a URI, if
present, is ignored.</p>
<p>SQLite uses the path component of the URI as the name of the disk file
which contains the database. If the path begins with a '/' character,
then it is interpreted as an absolute path. If the path does not begin
with a '/' (meaning that the authority section is omitted from the URI)
then the path is interpreted as a relative path.
On windows, the first component of an absolute path
is a drive specification (e.g. "C:").</p>
<p><a name="coreuriqueryparameters"></a>
The query component of a URI may contain parameters that are interpreted
either by SQLite itself, or by a <a href="vfs.html">custom VFS implementation</a>.
SQLite and its built-in <a href="vfs.html">VFSes</a> interpret the
following query parameters:</p>
<p><ul>
<li> <b>vfs</b>: The "vfs" parameter may be used to specify the name of
a VFS object that provides the operating system interface that should
be used to access the database file on disk. If this option is set to
an empty string the default VFS object is used. Specifying an unknown
VFS is an error. If sqlite3_open_v2() is used and the vfs option is
present, then the VFS specified by the option takes precedence over
the value passed as the fourth parameter to sqlite3_open_v2().</p>
<p><li> <b>mode</b>: The mode parameter may be set to either "ro", "rw",
"rwc", or "memory". Attempting to set it to any other value is
an error.
If "ro" is specified, then the database is opened for read-only
access, just as if the <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READONLY</a> flag had been set in the
third argument to sqlite3_open_v2(). If the mode option is set to
"rw", then the database is opened for read-write (but not create)
access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
been set. Value "rwc" is equivalent to setting both
SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. If the mode option is
set to "memory" then a pure <a href="inmemorydb.html">in-memory database</a> that never reads
or writes from disk is used. It is an error to specify a value for
the mode parameter that is less restrictive than that specified by
the flags passed in the third parameter to sqlite3_open_v2().</p>
<p><li> <b>cache</b>: The cache parameter may be set to either "shared" or
"private". Setting it to "shared" is equivalent to setting the
SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
sqlite3_open_v2(). Setting the cache parameter to "private" is
equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
If sqlite3_open_v2() is used and the "cache" parameter is present in
a URI filename, its value overrides any behavior requested by setting
SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.</p>
<p><li> <b>psow</b>: The psow parameter indicates whether or not the
<a href="psow.html">powersafe overwrite</a> property does or does not apply to the
storage media on which the database file resides.</p>
<p><li> <b>nolock</b>: The nolock parameter is a boolean query parameter
which if set disables file locking in rollback journal modes. This
is useful for accessing a database on a filesystem that does not
support locking. Caution: Database corruption might result if two
or more processes write to the same database and any one of those
processes uses nolock=1.</p>
<p><li> <b>immutable</b>: The immutable parameter is a boolean query
parameter that indicates that the database file is stored on
read-only media. When immutable is set, SQLite assumes that the
database file cannot be changed, even by a process with higher
privilege, and so the database is opened read-only and all locking
and change detection is disabled. Caution: Setting the immutable
property on a database file that does in fact change can result
in incorrect query results and/or <a href="#SQLITE_ABORT">SQLITE_CORRUPT</a> errors.
See also: <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_IMMUTABLE</a>.</p>
<p></ul></p>
<p>Specifying an unknown parameter in the query component of a URI is not an
error. Future versions of SQLite might understand additional query
parameters. See "<a href="uri.html#coreqp">query parameters with special meaning to SQLite</a>" for
additional information.</p>
<p><a name="urifilenameexamples"></a>
<h3>URI filename examples</h3></p>
<p><table border="1" align=center cellpadding=5>
<tr><th> URI filenames <th> Results
<tr><td> file:data.db <td>
Open the file "data.db" in the current directory.
<tr><td> file:/home/fred/data.db<br>
file:///home/fred/data.db <br>
file://localhost/home/fred/data.db <br> <td>
Open the database file "/home/fred/data.db".
<tr><td> file://darkstar/home/fred/data.db <td>
An error. "darkstar" is not a recognized authority.
<tr><td style="white-space:nowrap">
file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
<td> Windows only: Open the file "data.db" on fred's desktop on drive
C:. Note that the %20 escaping in this example is not strictly
necessary - space characters can be used literally
in URI filenames.
<tr><td> file:data.db?mode=ro&cache=private <td>
Open file "data.db" in the current directory for read-only access.
Regardless of whether or not shared-cache mode is enabled by
default, use a private cache.
<tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
that uses dot-files in place of posix advisory locking.
<tr><td> file:data.db?mode=readonly <td>
An error. "readonly" is not a valid option for the "mode" parameter.
Use "ro" instead: "file:data.db?mode=ro".
</table></p>
<p>URI hexadecimal escape sequences (%HH) are supported within the path and
query components of a URI. A hexadecimal escape sequence consists of a
percent sign - "%" - followed by exactly two hexadecimal digits
specifying an octet value. Before the path or query components of a
URI filename are interpreted, they are encoded using UTF-8 and all
hexadecimal escape sequences replaced by a single byte containing the
corresponding octet. If this process generates an invalid UTF-8 encoding,
the results are undefined.</p>
<p><b>Note to Windows users:</b> The encoding used for the filename argument
of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
codepage is currently defined. Filenames containing international
characters must be converted to UTF-8 prior to passing them into
sqlite3_open() or sqlite3_open_v2().</p>
<p><b>Note to Windows Runtime users:</b> The temporary directory must be set
prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
features that require the use of temporary files may fail.</p>
<p>See also: <a href="#sqlite3_temp_directory">sqlite3_temp_directory</a>
</p><hr><a name="sqlite3_preupdate_blobwrite"></a>
<h2>The pre-update hook.</h2>
</div>
<blockquote><pre>
#if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
void *sqlite3_preupdate_hook(
sqlite3 *db,
void(*xPreUpdate)(
void *pCtx, /* Copy of third arg to preupdate_hook() */
sqlite3 *db, /* Database handle */
int op, /* SQLITE_UPDATE, DELETE or INSERT */
char const *zDb, /* Database name */
char const *zName, /* Table name */
sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */
sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */
),
void*
);
int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
int sqlite3_preupdate_count(sqlite3 *);
int sqlite3_preupdate_depth(sqlite3 *);
int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
int sqlite3_preupdate_blobwrite(sqlite3 *);
#endif
</pre></blockquote>
<p>
These interfaces are only available if SQLite is compiled using the
<a href="compile.html#enable_preupdate_hook">SQLITE_ENABLE_PREUPDATE_HOOK</a> compile-time option.</p>
<p>The <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_hook()</a> interface registers a callback function
that is invoked prior to each <a href="lang_insert.html">INSERT</a>, <a href="lang_update.html">UPDATE</a>, and <a href="lang_delete.html">DELETE</a> operation
on a database table.
At most one preupdate hook may be registered at a time on a single
<a href="#sqlite3">database connection</a>; each call to <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_hook()</a> overrides
the previous setting.
The preupdate hook is disabled by invoking <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_hook()</a>
with a NULL pointer as the second parameter.
The third parameter to <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_hook()</a> is passed through as
the first parameter to callbacks.</p>
<p>The preupdate hook only fires for changes to real database tables; the
preupdate hook is not invoked for changes to <a href="vtab.html">virtual tables</a> or to
system tables like sqlite_sequence or sqlite_stat1.</p>
<p>The second parameter to the preupdate callback is a pointer to
the <a href="#sqlite3">database connection</a> that registered the preupdate hook.
The third parameter to the preupdate callback is one of the constants
<a href="#SQLITE_ALTER_TABLE">SQLITE_INSERT</a>, <a href="#SQLITE_ALTER_TABLE">SQLITE_DELETE</a>, or <a href="#SQLITE_ALTER_TABLE">SQLITE_UPDATE</a> to identify the
kind of update operation that is about to occur.
The fourth parameter to the preupdate callback is the name of the
database within the database connection that is being modified. This
will be "main" for the main database or "temp" for TEMP tables or
the name given after the AS keyword in the <a href="lang_attach.html">ATTACH</a> statement for attached
databases.
The fifth parameter to the preupdate callback is the name of the
table that is being modified.</p>
<p>For an UPDATE or DELETE operation on a <a href="rowidtable.html">rowid table</a>, the sixth
parameter passed to the preupdate callback is the initial <a href="lang_createtable.html#rowid">rowid</a> of the
row being modified or deleted. For an INSERT operation on a rowid table,
or any operation on a WITHOUT ROWID table, the value of the sixth
parameter is undefined. For an INSERT or UPDATE on a rowid table the
seventh parameter is the final rowid value of the row being inserted
or updated. The value of the seventh parameter passed to the callback
function is not defined for operations on WITHOUT ROWID tables, or for
DELETE operations on rowid tables.</p>
<p>The sqlite3_preupdate_hook(D,C,P) function returns the P argument from
the previous call on the same <a href="#sqlite3">database connection</a> D, or NULL for
the first call on D.</p>
<p>The <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_old()</a>, <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_new()</a>,
<a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_count()</a>, and <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_depth()</a> interfaces
provide additional information about a preupdate event. These routines
may only be called from within a preupdate callback. Invoking any of
these routines from outside of a preupdate callback or with a
<a href="#sqlite3">database connection</a> pointer that is different from the one supplied
to the preupdate callback results in undefined and probably undesirable
behavior.</p>
<p>The <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_count(D)</a> interface returns the number of columns
in the row that is being inserted, updated, or deleted.</p>
<p>The <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_old(D,N,P)</a> interface writes into P a pointer to
a <a href="#sqlite3_value">protected sqlite3_value</a> that contains the value of the Nth column of
the table row before it is updated. The N parameter must be between 0
and one less than the number of columns or the behavior will be
undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
behavior is undefined. The <a href="#sqlite3_value">sqlite3_value</a> that P points to
will be destroyed when the preupdate callback returns.</p>
<p>The <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_new(D,N,P)</a> interface writes into P a pointer to
a <a href="#sqlite3_value">protected sqlite3_value</a> that contains the value of the Nth column of
the table row after it is updated. The N parameter must be between 0
and one less than the number of columns or the behavior will be
undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
behavior is undefined. The <a href="#sqlite3_value">sqlite3_value</a> that P points to
will be destroyed when the preupdate callback returns.</p>
<p>The <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_depth(D)</a> interface returns 0 if the preupdate
callback was invoked as a result of a direct insert, update, or delete
operation; or 1 for inserts, updates, or deletes invoked by top-level
triggers; or 2 for changes resulting from triggers called by top-level
triggers; and so forth.</p>
<p>When the <a href="#sqlite3_blob_write">sqlite3_blob_write()</a> API is used to update a blob column,
the pre-update hook is invoked with SQLITE_DELETE. This is because the
in this case the new values are not available. In this case, when a
callback made with op==SQLITE_DELETE is actually a write using the
sqlite3_blob_write() API, the <a href="#sqlite3_preupdate_blobwrite">sqlite3_preupdate_blobwrite()</a> returns
the index of the column being written. In other cases, where the
pre-update hook is being invoked for some other reason, including a
regular DELETE, sqlite3_preupdate_blobwrite() returns -1.</p>
<p>See also: <a href="#sqlite3_update_hook">sqlite3_update_hook()</a>
</p><hr><a name="sqlite3_profile"></a>
<h2>Deprecated Tracing And Profiling Functions</h2>
</div>
<blockquote><pre>
void *sqlite3_trace(sqlite3*,
void(*xTrace)(void*,const char*), void*);
void *sqlite3_profile(sqlite3*,
void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
</pre></blockquote>
<p>
These routines are deprecated. Use the <a href="#sqlite3_trace_v2">sqlite3_trace_v2()</a> interface
instead of the routines described here.</p>
<p>These routines register callback functions that can be used for
tracing and profiling the execution of SQL statements.</p>
<p>The callback function registered by sqlite3_trace() is invoked at
various times when an SQL statement is being run by <a href="#sqlite3_step">sqlite3_step()</a>.
The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
SQL statement text as the statement first begins executing.
Additional sqlite3_trace() callbacks might occur
as each triggered subprogram is entered. The callbacks for triggers
contain a UTF-8 SQL comment that identifies the trigger.</p>
<p>The <a href="compile.html#trace_size_limit">SQLITE_TRACE_SIZE_LIMIT</a> compile-time option can be used to limit
the length of <a href="lang_expr.html#varparam">bound parameter</a> expansion in the output of sqlite3_trace().</p>
<p>The callback function registered by sqlite3_profile() is invoked
as each SQL statement finishes. The profile callback contains
the original statement text and an estimate of wall-clock time
of how long that statement took to run. The profile callback
time is in units of nanoseconds, however the current implementation
is only capable of millisecond resolution so the six least significant
digits in the time are meaningless. Future versions of SQLite
might provide greater resolution on the profiler callback. Invoking
either <a href="#sqlite3_profile">sqlite3_trace()</a> or <a href="#sqlite3_trace_v2">sqlite3_trace_v2()</a> will cancel the
profile callback.
</p><hr><a name="sqlite3_result_blob"></a>
<h2>Setting The Result Of An SQL Function</h2>
</div>
<blockquote><pre>
void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
void sqlite3_result_blob64(sqlite3_context*,const void*,
sqlite3_uint64,void(*)(void*));
void sqlite3_result_double(sqlite3_context*, double);
void sqlite3_result_error(sqlite3_context*, const char*, int);
void sqlite3_result_error16(sqlite3_context*, const void*, int);
void sqlite3_result_error_toobig(sqlite3_context*);
void sqlite3_result_error_nomem(sqlite3_context*);
void sqlite3_result_error_code(sqlite3_context*, int);
void sqlite3_result_int(sqlite3_context*, int);
void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
void sqlite3_result_null(sqlite3_context*);
void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
void(*)(void*), unsigned char encoding);
void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
void sqlite3_result_zeroblob(sqlite3_context*, int n);
int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
</pre></blockquote>
<p>
These routines are used by the xFunc or xFinal callbacks that
implement SQL functions and aggregates. See
<a href="#sqlite3_create_function">sqlite3_create_function()</a> and <a href="#sqlite3_create_function">sqlite3_create_function16()</a>
for additional information.</p>
<p>These functions work very much like the <a href="#sqlite3_bind_blob">parameter binding</a> family of
functions used to bind values to host parameters in prepared statements.
Refer to the <a href="#sqlite3_bind_blob">SQL parameter</a> documentation for additional information.</p>
<p>The sqlite3_result_blob() interface sets the result from
an application-defined function to be the BLOB whose content is pointed
to by the second parameter and which is N bytes long where N is the
third parameter.</p>
<p>The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
interfaces set the result of the application-defined function to be
a BLOB containing all zero bytes and N bytes in size.</p>
<p>The sqlite3_result_double() interface sets the result from
an application-defined function to be a floating point value specified
by its 2nd argument.</p>
<p>The sqlite3_result_error() and sqlite3_result_error16() functions
cause the implemented SQL function to throw an exception.
SQLite uses the string pointed to by the
2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
as the text of an error message. SQLite interprets the error
message string from sqlite3_result_error() as UTF-8. SQLite
interprets the string from sqlite3_result_error16() as UTF-16 using
the same <a href="#byteorderdeterminationrules">byte-order determination rules</a> as <a href="#sqlite3_bind_blob">sqlite3_bind_text16()</a>.
If the third parameter to sqlite3_result_error()
or sqlite3_result_error16() is negative then SQLite takes as the error
message all text up through the first zero character.
If the third parameter to sqlite3_result_error() or
sqlite3_result_error16() is non-negative then SQLite takes that many
bytes (not characters) from the 2nd parameter as the error message.
The sqlite3_result_error() and sqlite3_result_error16()
routines make a private copy of the error message text before
they return. Hence, the calling function can deallocate or
modify the text after they return without harm.
The sqlite3_result_error_code() function changes the error code
returned by SQLite as a result of an error in a function. By default,
the error code is SQLITE_ERROR. A subsequent call to sqlite3_result_error()
or sqlite3_result_error16() resets the error code to SQLITE_ERROR.</p>
<p>The sqlite3_result_error_toobig() interface causes SQLite to throw an
error indicating that a string or BLOB is too long to represent.</p>
<p>The sqlite3_result_error_nomem() interface causes SQLite to throw an
error indicating that a memory allocation failed.</p>
<p>The sqlite3_result_int() interface sets the return value
of the application-defined function to be the 32-bit signed integer
value given in the 2nd argument.
The sqlite3_result_int64() interface sets the return value
of the application-defined function to be the 64-bit signed integer
value given in the 2nd argument.</p>
<p>The sqlite3_result_null() interface sets the return value
of the application-defined function to be NULL.</p>
<p>The sqlite3_result_text(), sqlite3_result_text16(),
sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
set the return value of the application-defined function to be
a text string which is represented as UTF-8, UTF-16 native byte order,
UTF-16 little endian, or UTF-16 big endian, respectively.
The sqlite3_result_text64() interface sets the return value of an
application-defined function to be a text string in an encoding
specified by the fifth (and last) parameter, which must be one
of <a href="#SQLITE_ANY">SQLITE_UTF8</a>, <a href="#SQLITE_ANY">SQLITE_UTF16</a>, <a href="#SQLITE_ANY">SQLITE_UTF16BE</a>, or <a href="#SQLITE_ANY">SQLITE_UTF16LE</a>.
SQLite takes the text result from the application from
the 2nd parameter of the sqlite3_result_text* interfaces.
If the 3rd parameter to any of the sqlite3_result_text* interfaces
other than sqlite3_result_text64() is negative, then SQLite computes
the string length itself by searching the 2nd parameter for the first
zero character.
If the 3rd parameter to the sqlite3_result_text* interfaces
is non-negative, then as many bytes (not characters) of the text
pointed to by the 2nd parameter are taken as the application-defined
function result. If the 3rd parameter is non-negative, then it
must be the byte offset into the string where the NUL terminator would
appear if the string where NUL terminated. If any NUL characters occur
in the string at a byte offset that is less than the value of the 3rd
parameter, then the resulting string will contain embedded NULs and the
result of expressions operating on strings with embedded NULs is undefined.
If the 4th parameter to the sqlite3_result_text* interfaces
or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
function as the destructor on the text or BLOB result when it has
finished using that result.
If the 4th parameter to the sqlite3_result_text* interfaces or to
sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
assumes that the text or BLOB result is in constant space and does not
copy the content of the parameter nor call a destructor on the content
when it has finished using that result.
If the 4th parameter to the sqlite3_result_text* interfaces
or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
then SQLite makes a copy of the result into space obtained
from <a href="#sqlite3_free">sqlite3_malloc()</a> before it returns.</p>
<p>For the sqlite3_result_text16(), sqlite3_result_text16le(), and
sqlite3_result_text16be() routines, and for sqlite3_result_text64()
when the encoding is not UTF8, if the input UTF16 begins with a
byte-order mark (BOM, U+FEFF) then the BOM is removed from the
string and the rest of the string is interpreted according to the
byte-order specified by the BOM. The byte-order specified by
the BOM at the beginning of the text overrides the byte-order
specified by the interface procedure. So, for example, if
sqlite3_result_text16le() is invoked with text that begins
with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
first two bytes of input are skipped and the remaining input
is interpreted as UTF16BE text.</p>
<p>For UTF16 input text to the sqlite3_result_text16(),
sqlite3_result_text16be(), sqlite3_result_text16le(), and
sqlite3_result_text64() routines, if the text contains invalid
UTF16 characters, the invalid characters might be converted
into the unicode replacement character, U+FFFD.</p>
<p>The sqlite3_result_value() interface sets the result of
the application-defined function to be a copy of the
<a href="#sqlite3_value">unprotected sqlite3_value</a> object specified by the 2nd parameter. The
sqlite3_result_value() interface makes a copy of the <a href="#sqlite3_value">sqlite3_value</a>
so that the <a href="#sqlite3_value">sqlite3_value</a> specified in the parameter may change or
be deallocated after sqlite3_result_value() returns without harm.
A <a href="#sqlite3_value">protected sqlite3_value</a> object may always be used where an
<a href="#sqlite3_value">unprotected sqlite3_value</a> object is required, so either
kind of <a href="#sqlite3_value">sqlite3_value</a> object can be used with this interface.</p>
<p>The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
SQL NULL value, just like <a href="#sqlite3_result_blob">sqlite3_result_null(C)</a>, except that it
also associates the host-language pointer P or type T with that
NULL value such that the pointer can be retrieved within an
<a href="appfunc.html">application-defined SQL function</a> using <a href="#sqlite3_value_blob">sqlite3_value_pointer()</a>.
If the D parameter is not NULL, then it is a pointer to a destructor
for the P parameter. SQLite invokes D with P as its only argument
when SQLite is finished with P. The T parameter should be a static
string and preferably a string literal. The sqlite3_result_pointer()
routine is part of the <a href="bindptr.html">pointer passing interface</a> added for SQLite 3.20.0.</p>
<p>If these routines are called from within the different thread
than the one containing the application-defined function that received
the <a href="#sqlite3_context">sqlite3_context</a> pointer, the results are undefined.
</p><hr><a name="sqlite3_status"></a>
<h2>SQLite Runtime Status</h2>
</div>
<blockquote><pre>
int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
int sqlite3_status64(
int op,
sqlite3_int64 *pCurrent,
sqlite3_int64 *pHighwater,
int resetFlag
);
</pre></blockquote>
<p>
These interfaces are used to retrieve runtime status information
about the performance of SQLite, and optionally to reset various
highwater marks. The first argument is an integer code for
the specific parameter to measure. Recognized integer codes
are of the form <a href="#SQLITE_STATUS_MALLOC_COUNT">SQLITE_STATUS_...</a>.
The current value of the parameter is returned into *pCurrent.
The highest recorded value is returned in *pHighwater. If the
resetFlag is true, then the highest record value is reset after
*pHighwater is written. Some parameters do not record the highest
value. For those parameters
nothing is written into *pHighwater and the resetFlag is ignored.
Other parameters record only the highwater mark and not the current
value. For these latter parameters nothing is written into *pCurrent.</p>
<p>The sqlite3_status() and sqlite3_status64() routines return
SQLITE_OK on success and a non-zero <a href="rescode.html">error code</a> on failure.</p>
<p>If either the current value or the highwater mark is too large to
be represented by a 32-bit integer, then the values returned by
sqlite3_status() are undefined.</p>
<p>See also: <a href="#sqlite3_db_status">sqlite3_db_status()</a>
</p><hr><a name="sqlite3_stmt_scanstatus"></a>
<h2>Prepared Statement Scan Status</h2>
</div>
<blockquote><pre>
int sqlite3_stmt_scanstatus(
sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
int idx, /* Index of loop to report on */
int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
void *pOut /* Result written here */
);
int sqlite3_stmt_scanstatus_v2(
sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
int idx, /* Index of loop to report on */
int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
int flags, /* Mask of flags defined below */
void *pOut /* Result written here */
);
</pre></blockquote>
<p>
These interfaces return information about the predicted and measured
performance for pStmt. Advanced applications can use this
interface to compare the predicted and the measured performance and
issue warnings and/or rerun <a href="lang_analyze.html">ANALYZE</a> if discrepancies are found.</p>
<p>Since this interface is expected to be rarely used, it is only
available if SQLite is compiled using the <a href="compile.html#enable_stmt_scanstatus">SQLITE_ENABLE_STMT_SCANSTATUS</a>
compile-time option.</p>
<p>The "iScanStatusOp" parameter determines which status information to return.
The "iScanStatusOp" must be one of the <a href="#SQLITE_SCANSTAT_EST">scanstatus options</a> or the behavior
of this interface is undefined. The requested measurement is written into
a variable pointed to by the "pOut" parameter.</p>
<p>The "flags" parameter must be passed a mask of flags. At present only
one flag is defined - SQLITE_SCANSTAT_COMPLEX. If SQLITE_SCANSTAT_COMPLEX
is specified, then status information is available for all elements
of a query plan that are reported by "EXPLAIN QUERY PLAN" output. If
SQLITE_SCANSTAT_COMPLEX is not specified, then only query plan elements
that correspond to query loops (the "SCAN..." and "SEARCH..." elements of
the EXPLAIN QUERY PLAN output) are available. Invoking API
sqlite3_stmt_scanstatus() is equivalent to calling
sqlite3_stmt_scanstatus_v2() with a zeroed flags parameter.</p>
<p>Parameter "idx" identifies the specific query element to retrieve statistics
for. Query elements are numbered starting from zero. A value of -1 may be
to query for statistics regarding the entire query. If idx is out of range
- less than -1 or greater than or equal to the total number of query
elements used to implement the statement - a non-zero value is returned and
the variable that pOut points to is unchanged.</p>
<p>See also: <a href="#sqlite3_stmt_scanstatus_reset">sqlite3_stmt_scanstatus_reset()</a>
</p><hr><a name="sqlite3_str_append"></a>
<h2>Add Content To A Dynamic String</h2>
</div>
<blockquote><pre>
void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
void sqlite3_str_reset(sqlite3_str*);
</pre></blockquote>
<p>
These interfaces add content to an sqlite3_str object previously obtained
from <a href="#sqlite3_str_new">sqlite3_str_new()</a>.</p>
<p>The <a href="#sqlite3_str_append">sqlite3_str_appendf(X,F,...)</a> and
<a href="#sqlite3_str_append">sqlite3_str_vappendf(X,F,V)</a> interfaces uses the <a href="printf.html">built-in printf</a>
functionality of SQLite to append formatted text onto the end of
<a href="#sqlite3_str">sqlite3_str</a> object X.</p>
<p>The <a href="#sqlite3_str_append">sqlite3_str_append(X,S,N)</a> method appends exactly N bytes from string S
onto the end of the <a href="#sqlite3_str">sqlite3_str</a> object X. N must be non-negative.
S must contain at least N non-zero bytes of content. To append a
zero-terminated string in its entirety, use the <a href="#sqlite3_str_append">sqlite3_str_appendall()</a>
method instead.</p>
<p>The <a href="#sqlite3_str_append">sqlite3_str_appendall(X,S)</a> method appends the complete content of
zero-terminated string S onto the end of <a href="#sqlite3_str">sqlite3_str</a> object X.</p>
<p>The <a href="#sqlite3_str_append">sqlite3_str_appendchar(X,N,C)</a> method appends N copies of the
single-byte character C onto the end of <a href="#sqlite3_str">sqlite3_str</a> object X.
This method can be used, for example, to add whitespace indentation.</p>
<p>The <a href="#sqlite3_str_append">sqlite3_str_reset(X)</a> method resets the string under construction
inside <a href="#sqlite3_str">sqlite3_str</a> object X back to zero bytes in length.</p>
<p>These methods do not return a result code. If an error occurs, that fact
is recorded in the <a href="#sqlite3_str">sqlite3_str</a> object and can be recovered by a
subsequent call to <a href="#sqlite3_str_errcode">sqlite3_str_errcode(X)</a>.
</p><hr><a name="sqlite3_str_errcode"></a>
<h2>Status Of A Dynamic String</h2>
</div>
<blockquote><pre>
int sqlite3_str_errcode(sqlite3_str*);
int sqlite3_str_length(sqlite3_str*);
char *sqlite3_str_value(sqlite3_str*);
</pre></blockquote>
<p>
These interfaces return the current status of an <a href="#sqlite3_str">sqlite3_str</a> object.</p>
<p>If any prior errors have occurred while constructing the dynamic string
in sqlite3_str X, then the <a href="#sqlite3_str_errcode">sqlite3_str_errcode(X)</a> method will return
an appropriate error code. The <a href="#sqlite3_str_errcode">sqlite3_str_errcode(X)</a> method returns
<a href="#SQLITE_ABORT">SQLITE_NOMEM</a> following any out-of-memory error, or
<a href="#SQLITE_ABORT">SQLITE_TOOBIG</a> if the size of the dynamic string exceeds
<a href="limits.html#max_length">SQLITE_MAX_LENGTH</a>, or <a href="#SQLITE_ABORT">SQLITE_OK</a> if there have been no errors.</p>
<p>The <a href="#sqlite3_str_errcode">sqlite3_str_length(X)</a> method returns the current length, in bytes,
of the dynamic string under construction in <a href="#sqlite3_str">sqlite3_str</a> object X.
The length returned by <a href="#sqlite3_str_errcode">sqlite3_str_length(X)</a> does not include the
zero-termination byte.</p>
<p>The <a href="#sqlite3_str_errcode">sqlite3_str_value(X)</a> method returns a pointer to the current
content of the dynamic string under construction in X. The value
returned by <a href="#sqlite3_str_errcode">sqlite3_str_value(X)</a> is managed by the sqlite3_str object X
and might be freed or altered by any subsequent method on the same
<a href="#sqlite3_str">sqlite3_str</a> object. Applications must not used the pointer returned
<a href="#sqlite3_str_errcode">sqlite3_str_value(X)</a> after any subsequent method call on the same
object. Applications may change the content of the string returned
by <a href="#sqlite3_str_errcode">sqlite3_str_value(X)</a> as long as they do not write into any bytes
outside the range of 0 to <a href="#sqlite3_str_errcode">sqlite3_str_length(X)</a> and do not read or
write any byte after any subsequent sqlite3_str method call.
</p><hr><a name="sqlite3_stricmp"></a>
<h2>String Comparison</h2>
</div>
<blockquote><pre>
int sqlite3_stricmp(const char *, const char *);
int sqlite3_strnicmp(const char *, const char *, int);
</pre></blockquote>
<p>
The <a href="#sqlite3_stricmp">sqlite3_stricmp()</a> and <a href="#sqlite3_stricmp">sqlite3_strnicmp()</a> APIs allow applications
and extensions to compare the contents of two buffers containing UTF-8
strings in a case-independent fashion, using the same definition of "case
independence" that SQLite uses internally when comparing identifiers.
</p><hr><a name="sqlite3_total_changes"></a>
<h2>Total Number Of Rows Modified</h2>
</div>
<blockquote><pre>
int sqlite3_total_changes(sqlite3*);
sqlite3_int64 sqlite3_total_changes64(sqlite3*);
</pre></blockquote>
<p>
These functions return the total number of rows inserted, modified or
deleted by all <a href="lang_insert.html">INSERT</a>, <a href="lang_update.html">UPDATE</a> or <a href="lang_delete.html">DELETE</a> statements completed
since the database connection was opened, including those executed as
part of trigger programs. The two functions are identical except for the
type of the return value and that if the number of rows modified by the
connection exceeds the maximum value supported by type "int", then
the return value of sqlite3_total_changes() is undefined. Executing
any other type of SQL statement does not affect the value returned by
sqlite3_total_changes().</p>
<p>Changes made as part of <a href="foreignkeys.html#fk_actions">foreign key actions</a> are included in the
count, but those made as part of REPLACE constraint resolution are
not. Changes to a view that are intercepted by INSTEAD OF triggers
are not counted.</p>
<p>The <a href="#sqlite3_total_changes">sqlite3_total_changes(D)</a> interface only reports the number
of rows that changed due to SQL statement run against database
connection D. Any changes by other database connections are ignored.
To detect changes against a database file from other database
connections use the <a href="pragma.html#pragma_data_version">PRAGMA data_version</a> command or the
<a href="#sqlitefcntldataversion">SQLITE_FCNTL_DATA_VERSION</a> <a href="#sqlite3_file_control">file control</a>.</p>
<p>If a separate thread makes changes on the same database connection
while <a href="#sqlite3_total_changes">sqlite3_total_changes()</a> is running then the value
returned is unpredictable and not meaningful.</p>
<p>See also:
<ul>
<li> the <a href="#sqlite3_changes">sqlite3_changes()</a> interface
<li> the <a href="pragma.html#pragma_count_changes">count_changes pragma</a>
<li> the <a href="lang_corefunc.html#changes">changes() SQL function</a>
<li> the <a href="pragma.html#pragma_data_version">data_version pragma</a>
<li> the <a href="#sqlitefcntldataversion">SQLITE_FCNTL_DATA_VERSION</a> <a href="#sqlite3_file_control">file control</a>
</ul>
</p><hr><a name="sqlite3_uri_boolean"></a>
<h2>Obtain Values For URI Parameters</h2>
</div>
<blockquote><pre>
const char *sqlite3_uri_parameter(sqlite3_filename z, const char *zParam);
int sqlite3_uri_boolean(sqlite3_filename z, const char *zParam, int bDefault);
sqlite3_int64 sqlite3_uri_int64(sqlite3_filename, const char*, sqlite3_int64);
const char *sqlite3_uri_key(sqlite3_filename z, int N);
</pre></blockquote>
<p>
These are utility routines, useful to <a href="vfs.html">custom VFS implementations</a>,
that check if a database file was a URI that contained a specific query
parameter, and if so obtains the value of that query parameter.</p>
<p>The first parameter to these interfaces (hereafter referred to
as F) must be one of:
<ul>
<li> A database filename pointer created by the SQLite core and
passed into the xOpen() method of a VFS implementation, or
<li> A filename obtained from <a href="#sqlite3_db_filename">sqlite3_db_filename()</a>, or
<li> A new filename constructed using <a href="#sqlite3_create_filename">sqlite3_create_filename()</a>.
</ul>
If the F parameter is not one of the above, then the behavior is
undefined and probably undesirable. Older versions of SQLite were
more tolerant of invalid F parameters than newer versions.</p>
<p>If F is a suitable filename (as described in the previous paragraph)
and if P is the name of the query parameter, then
sqlite3_uri_parameter(F,P) returns the value of the P
parameter if it exists or a NULL pointer if P does not appear as a
query parameter on F. If P is a query parameter of F and it
has no explicit value, then sqlite3_uri_parameter(F,P) returns
a pointer to an empty string.</p>
<p>The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
parameter and returns true (1) or false (0) according to the value
of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
value of query parameter P is one of "yes", "true", or "on" in any
case or if the value begins with a non-zero number. The
sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
query parameter P is one of "no", "false", or "off" in any case or
if the value begins with a numeric zero. If P is not a query
parameter on F or if the value of P does not match any of the
above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).</p>
<p>The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
64-bit signed integer and returns that integer, or D if P does not
exist. If the value of P is something other than an integer, then
zero is returned.</p>
<p>The sqlite3_uri_key(F,N) returns a pointer to the name (not
the value) of the N-th query parameter for filename F, or a NULL
pointer if N is less than zero or greater than the number of query
parameters minus 1. The N value is zero-based so N should be 0 to obtain
the name of the first query parameter, 1 for the second parameter, and
so forth.</p>
<p>If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
is not a database file pathname pointer that the SQLite core passed
into the xOpen VFS method, then the behavior of this routine is undefined
and probably undesirable.</p>
<p>Beginning with SQLite <a href="releaselog/3_31_0.html">version 3.31.0</a> (2020-01-22) the input F
parameter can also be the name of a rollback journal file or WAL file
in addition to the main database file. Prior to version 3.31.0, these
routines would only work if F was the name of the main database file.
When the F parameter is the name of the rollback journal or WAL file,
it has access to all the same query parameters as were found on the
main database file.</p>
<p>See the <a href="uri.html">URI filename</a> documentation for additional information.
</p><hr><a name="sqlite3_value_blob"></a>
<h2>Obtaining SQL Values</h2>
</div>
<blockquote><pre>
const void *sqlite3_value_blob(sqlite3_value*);
double sqlite3_value_double(sqlite3_value*);
int sqlite3_value_int(sqlite3_value*);
sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
void *sqlite3_value_pointer(sqlite3_value*, const char*);
const unsigned char *sqlite3_value_text(sqlite3_value*);
const void *sqlite3_value_text16(sqlite3_value*);
const void *sqlite3_value_text16le(sqlite3_value*);
const void *sqlite3_value_text16be(sqlite3_value*);
int sqlite3_value_bytes(sqlite3_value*);
int sqlite3_value_bytes16(sqlite3_value*);
int sqlite3_value_type(sqlite3_value*);
int sqlite3_value_numeric_type(sqlite3_value*);
int sqlite3_value_nochange(sqlite3_value*);
int sqlite3_value_frombind(sqlite3_value*);
</pre></blockquote>
<p>
<b>Summary:</b>
<blockquote><table border=0 cellpadding=0 cellspacing=0>
<tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value
<tr><td><b>sqlite3_value_double</b><td>→<td>REAL value
<tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value
<tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value
<tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value
<tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value
<tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in
the native byteorder
<tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value
<tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value
<tr><td> <td> <td>
<tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB
or a UTF-8 TEXT in bytes
<tr><td><b>sqlite3_value_bytes16 </b>
<td>→ <td>Size of UTF-16
TEXT in bytes
<tr><td><b>sqlite3_value_type</b><td>→<td>Default
datatype of the value
<tr><td><b>sqlite3_value_numeric_type </b>
<td>→ <td>Best numeric datatype of the value
<tr><td><b>sqlite3_value_nochange </b>
<td>→ <td>True if the column is unchanged in an UPDATE
against a virtual table.
<tr><td><b>sqlite3_value_frombind </b>
<td>→ <td>True if value originated from a <a href="lang_expr.html#varparam">bound parameter</a>
</table></blockquote></p>
<p><b>Details:</b></p>
<p>These routines extract type, size, and content information from
<a href="#sqlite3_value">protected sqlite3_value</a> objects. Protected sqlite3_value objects
are used to pass parameter information into the functions that
implement <a href="appfunc.html">application-defined SQL functions</a> and <a href="vtab.html">virtual tables</a>.</p>
<p>These routines work only with <a href="#sqlite3_value">protected sqlite3_value</a> objects.
Any attempt to use these routines on an <a href="#sqlite3_value">unprotected sqlite3_value</a>
is not threadsafe.</p>
<p>These routines work just like the corresponding <a href="#sqlite3_column_blob">column access functions</a>
except that these routines take a single <a href="#sqlite3_value">protected sqlite3_value</a> object
pointer instead of a <a href="#sqlite3_stmt">sqlite3_stmt*</a> pointer and an integer column number.</p>
<p>The sqlite3_value_text16() interface extracts a UTF-16 string
in the native byte-order of the host machine. The
sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
extract UTF-16 strings as big-endian and little-endian respectively.</p>
<p>If <a href="#sqlite3_value">sqlite3_value</a> object V was initialized
using <a href="#sqlite3_bind_blob">sqlite3_bind_pointer(S,I,P,X,D)</a> or <a href="#sqlite3_result_blob">sqlite3_result_pointer(C,P,X,D)</a>
and if X and Y are strings that compare equal according to strcmp(X,Y),
then sqlite3_value_pointer(V,Y) will return the pointer P. Otherwise,
sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
routine is part of the <a href="bindptr.html">pointer passing interface</a> added for SQLite 3.20.0.</p>
<p>The sqlite3_value_type(V) interface returns the
<a href="#SQLITE_BLOB">datatype code</a> for the initial datatype of the
<a href="#sqlite3_value">sqlite3_value</a> object V. The returned value is one of <a href="#SQLITE_BLOB">SQLITE_INTEGER</a>,
<a href="#SQLITE_BLOB">SQLITE_FLOAT</a>, <a href="#SQLITE_BLOB">SQLITE_TEXT</a>, <a href="#SQLITE_BLOB">SQLITE_BLOB</a>, or <a href="#SQLITE_BLOB">SQLITE_NULL</a>.
Other interfaces might change the datatype for an sqlite3_value object.
For example, if the datatype is initially SQLITE_INTEGER and
sqlite3_value_text(V) is called to extract a text value for that
integer, then subsequent calls to sqlite3_value_type(V) might return
SQLITE_TEXT. Whether or not a persistent internal datatype conversion
occurs is undefined and may change from one release of SQLite to the next.</p>
<p>The sqlite3_value_numeric_type() interface attempts to apply
numeric affinity to the value. This means that an attempt is
made to convert the value to an integer or floating point. If
such a conversion is possible without loss of information (in other
words, if the value is a string that looks like a number)
then the conversion is performed. Otherwise no conversion occurs.
The <a href="#SQLITE_BLOB">datatype</a> after conversion is returned.</p>
<p>Within the <a href="vtab.html#xupdate">xUpdate</a> method of a <a href="vtab.html">virtual table</a>, the
sqlite3_value_nochange(X) interface returns true if and only if
the column corresponding to X is unchanged by the UPDATE operation
that the xUpdate method call was invoked to implement and if
and the prior <a href="vtab.html#xcolumn">xColumn</a> method call that was invoked to extracted
the value for that column returned without setting a result (probably
because it queried <a href="#sqlite3_vtab_nochange">sqlite3_vtab_nochange()</a> and found that the column
was unchanging). Within an <a href="vtab.html#xupdate">xUpdate</a> method, any value for which
sqlite3_value_nochange(X) is true will in all other respects appear
to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other
than within an <a href="vtab.html#xupdate">xUpdate</a> method call for an UPDATE statement, then
the return value is arbitrary and meaningless.</p>
<p>The sqlite3_value_frombind(X) interface returns non-zero if the
value X originated from one of the <a href="#sqlite3_bind_blob">sqlite3_bind()</a>
interfaces. If X comes from an SQL literal value, or a table column,
or an expression, then sqlite3_value_frombind(X) returns zero.</p>
<p>Please pay particular attention to the fact that the pointer returned
from <a href="#sqlite3_value_blob">sqlite3_value_blob()</a>, <a href="#sqlite3_value_blob">sqlite3_value_text()</a>, or
<a href="#sqlite3_value_blob">sqlite3_value_text16()</a> can be invalidated by a subsequent call to
<a href="#sqlite3_value_blob">sqlite3_value_bytes()</a>, <a href="#sqlite3_value_blob">sqlite3_value_bytes16()</a>, <a href="#sqlite3_value_blob">sqlite3_value_text()</a>,
or <a href="#sqlite3_value_blob">sqlite3_value_text16()</a>.</p>
<p>These routines must be called from the same thread as
the SQL function that supplied the <a href="#sqlite3_value">sqlite3_value*</a> parameters.</p>
<p>As long as the input parameter is correct, these routines can only
fail if an out-of-memory error occurs during a format conversion.
Only the following subset of interfaces are subject to out-of-memory
errors:</p>
<p><ul>
<li> sqlite3_value_blob()
<li> sqlite3_value_text()
<li> sqlite3_value_text16()
<li> sqlite3_value_text16le()
<li> sqlite3_value_text16be()
<li> sqlite3_value_bytes()
<li> sqlite3_value_bytes16()
</ul></p>
<p>If an out-of-memory error occurs, then the return value from these
routines is the same as if the column had contained an SQL NULL value.
Valid SQL NULL returns can be distinguished from out-of-memory errors
by invoking the <a href="#sqlite3_errcode">sqlite3_errcode()</a> immediately after the suspect
return value is obtained and before any
other SQLite interface is called on the same <a href="#sqlite3">database connection</a>.
</p><hr><a name="sqlite3_value_dup"></a>
<h2>Copy And Free SQL Values</h2>
</div>
<blockquote><pre>
sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
void sqlite3_value_free(sqlite3_value*);
</pre></blockquote>
<p>
The sqlite3_value_dup(V) interface makes a copy of the <a href="#sqlite3_value">sqlite3_value</a>
object D and returns a pointer to that copy. The <a href="#sqlite3_value">sqlite3_value</a> returned
is a <a href="#sqlite3_value">protected sqlite3_value</a> object even if the input is not.
The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
memory allocation fails. If V is a <a href="bindptr.html">pointer value</a>, then the result
of sqlite3_value_dup(V) is a NULL value.</p>
<p>The sqlite3_value_free(V) interface frees an <a href="#sqlite3_value">sqlite3_value</a> object
previously obtained from <a href="#sqlite3_value_dup">sqlite3_value_dup()</a>. If V is a NULL pointer
then sqlite3_value_free(V) is a harmless no-op.
</p><hr><a name="sqlite3_vfs_find"></a>
<h2>Virtual File System Objects</h2>
</div>
<blockquote><pre>
sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
int sqlite3_vfs_unregister(sqlite3_vfs*);
</pre></blockquote>
<p>
A virtual filesystem (VFS) is an <a href="#sqlite3_vfs">sqlite3_vfs</a> object
that SQLite uses to interact
with the underlying operating system. Most SQLite builds come with a
single default VFS that is appropriate for the host computer.
New VFSes can be registered and existing VFSes can be unregistered.
The following interfaces are provided.</p>
<p>The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
Names are case sensitive.
Names are zero-terminated UTF-8 strings.
If there is no match, a NULL pointer is returned.
If zVfsName is NULL then the default VFS is returned.</p>
<p>New VFSes are registered with sqlite3_vfs_register().
Each new VFS becomes the default VFS if the makeDflt flag is set.
The same VFS can be registered multiple times without injury.
To make an existing VFS into the default VFS, register it again
with the makeDflt flag set. If two different VFSes with the
same name are registered, the behavior is undefined. If a
VFS is registered with a name that is NULL or an empty string,
then the behavior is undefined.</p>
<p>Unregister a VFS with the sqlite3_vfs_unregister() interface.
If the default VFS is unregistered, another VFS is chosen as
the default. The choice for the new VFS is arbitrary.
</p><hr><a name="sqlite3_vtab_in_first"></a>
<h2>Find all elements on the right-hand side of an IN constraint.</h2>
</div>
<blockquote><pre>
int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut);
int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut);
</pre></blockquote>
<p>
These interfaces are only useful from within the
<a href="vtab.html#xfilter">xFilter() method</a> of a <a href="vtab.html">virtual table</a> implementation.
The result of invoking these interfaces from any other context
is undefined and probably harmful.</p>
<p>The X parameter in a call to sqlite3_vtab_in_first(X,P) or
sqlite3_vtab_in_next(X,P) should be one of the parameters to the
xFilter method which invokes these routines, and specifically
a parameter that was previously selected for all-at-once IN constraint
processing use the <a href="#sqlite3_vtab_in">sqlite3_vtab_in()</a> interface in the
<a href="vtab.html#xbestindex">xBestIndex method</a>. If the X parameter is not
an xFilter argument that was selected for all-at-once IN constraint
processing, then these routines return <a href="#SQLITE_ABORT">SQLITE_ERROR</a>.</p>
<p>Use these routines to access all values on the right-hand side
of the IN constraint using code like the following:</p>
<p><blockquote><pre>
for(rc=sqlite3_vtab_in_first(pList, &pVal);
rc==SQLITE_OK && pVal;
rc=sqlite3_vtab_in_next(pList, &pVal)
){
// do something with pVal
}
if( rc!=SQLITE_OK ){
// an error has occurred
}
</pre></blockquote></p>
<p>On success, the sqlite3_vtab_in_first(X,P) and sqlite3_vtab_in_next(X,P)
routines return SQLITE_OK and set *P to point to the first or next value
on the RHS of the IN constraint. If there are no more values on the
right hand side of the IN constraint, then *P is set to NULL and these
routines return <a href="#SQLITE_ABORT">SQLITE_DONE</a>. The return value might be
some other value, such as SQLITE_NOMEM, in the event of a malfunction.</p>
<p>The *ppOut values returned by these routines are only valid until the
next call to either of these routines or until the end of the xFilter
method from which these routines were called. If the virtual table
implementation needs to retain the *ppOut values for longer, it must make
copies. The *ppOut values are <a href="#sqlite3_value">protected</a>.
</p><hr><a name="sqlite3_win32_set_directory"></a>
<h2>Win32 Specific Interface</h2>
</div>
<blockquote><pre>
int sqlite3_win32_set_directory(
unsigned long type, /* Identifier for directory being set or reset */
void *zValue /* New value for directory being set or reset */
);
int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
</pre></blockquote>
<p>
These interfaces are available only on Windows. The
<a href="#sqlite3_win32_set_directory">sqlite3_win32_set_directory</a> interface is used to set the value associated
with the <a href="#sqlite3_temp_directory">sqlite3_temp_directory</a> or <a href="#sqlite3_data_directory">sqlite3_data_directory</a> variable, to
zValue, depending on the value of the type parameter. The zValue parameter
should be NULL to cause the previous value to be freed via <a href="#sqlite3_free">sqlite3_free</a>;
a non-NULL value will be copied into memory obtained from <a href="#sqlite3_free">sqlite3_malloc</a>
prior to being used. The <a href="#sqlite3_win32_set_directory">sqlite3_win32_set_directory</a> interface returns
<a href="#SQLITE_ABORT">SQLITE_OK</a> to indicate success, <a href="#SQLITE_ABORT">SQLITE_ERROR</a> if the type is unsupported,
or <a href="#SQLITE_ABORT">SQLITE_NOMEM</a> if memory could not be allocated. The value of the
<a href="#sqlite3_data_directory">sqlite3_data_directory</a> variable is intended to act as a replacement for
the current directory on the sub-platforms of Win32 where that concept is
not present, e.g. WinRT and UWP. The <a href="#sqlite3_win32_set_directory">sqlite3_win32_set_directory8</a> and
<a href="#sqlite3_win32_set_directory">sqlite3_win32_set_directory16</a> interfaces behave exactly the same as the
sqlite3_win32_set_directory interface except the string parameter must be
UTF-8 or UTF-16, respectively.
</p><hr><a name="sqlite3_bind_blob"></a>
<h2>Binding Values To Prepared Statements</h2>
</div>
<blockquote><pre>
int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
void(*)(void*));
int sqlite3_bind_double(sqlite3_stmt*, int, double);
int sqlite3_bind_int(sqlite3_stmt*, int, int);
int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
int sqlite3_bind_null(sqlite3_stmt*, int);
int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
void(*)(void*), unsigned char encoding);
int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
</pre></blockquote>
<p>
In the SQL statement text input to <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> and its variants,
literals may be replaced by a <a href="lang_expr.html#varparam">parameter</a> that matches one of following
templates:</p>
<p><ul>
<li> ?
<li> ?NNN
<li> :VVV
<li> @VVV
<li> $VVV
</ul></p>
<p>In the templates above, NNN represents an integer literal,
and VVV represents an alphanumeric identifier. The values of these
parameters (also called "host parameter names" or "SQL parameters")
can be set using the sqlite3_bind_*() routines defined here.</p>
<p>The first argument to the sqlite3_bind_*() routines is always
a pointer to the <a href="#sqlite3_stmt">sqlite3_stmt</a> object returned from
<a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> or its variants.</p>
<p>The second argument is the index of the SQL parameter to be set.
The leftmost SQL parameter has an index of 1. When the same named
SQL parameter is used more than once, second and subsequent
occurrences have the same index as the first occurrence.
The index for named parameters can be looked up using the
<a href="#sqlite3_bind_parameter_index">sqlite3_bind_parameter_index()</a> API if desired. The index
for "?NNN" parameters is the value of NNN.
The NNN value must be between 1 and the <a href="#sqlite3_limit">sqlite3_limit()</a>
parameter <a href="#sqlitelimitvariablenumber">SQLITE_LIMIT_VARIABLE_NUMBER</a> (default value: 32766).</p>
<p>The third argument is the value to bind to the parameter.
If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
is ignored and the end result is the same as sqlite3_bind_null().
If the third parameter to sqlite3_bind_text() is not NULL, then
it should be a pointer to well-formed UTF8 text.
If the third parameter to sqlite3_bind_text16() is not NULL, then
it should be a pointer to well-formed UTF16 text.
If the third parameter to sqlite3_bind_text64() is not NULL, then
it should be a pointer to a well-formed unicode string that is
either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
otherwise.</p>
<p><a name="byteorderdeterminationrules"></a>
The byte-order of
UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
found in first character, which is removed, or in the absence of a BOM
the byte order is the native byte order of the host
machine for sqlite3_bind_text16() or the byte order specified in
the 6th parameter for sqlite3_bind_text64().
If UTF16 input text contains invalid unicode
characters, then SQLite might change those invalid characters
into the unicode replacement character: U+FFFD.</p>
<p>In those routines that have a fourth argument, its value is the
number of bytes in the parameter. To be clear: the value is the
number of <u>bytes</u> in the value, not the number of characters.
If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
is negative, then the length of the string is
the number of bytes up to the first zero terminator.
If the fourth parameter to sqlite3_bind_blob() is negative, then
the behavior is undefined.
If a non-negative fourth parameter is provided to sqlite3_bind_text()
or sqlite3_bind_text16() or sqlite3_bind_text64() then
that parameter must be the byte offset
where the NUL terminator would occur assuming the string were NUL
terminated. If any NUL characters occurs at byte offsets less than
the value of the fourth parameter then the resulting string value will
contain embedded NULs. The result of expressions involving strings
with embedded NULs is undefined.</p>
<p>The fifth argument to the BLOB and string binding interfaces controls
or indicates the lifetime of the object referenced by the third parameter.
These three options exist:
(1) A destructor to dispose of the BLOB or string after SQLite has finished
with it may be passed. It is called to dispose of the BLOB or string even
if the call to the bind API fails, except the destructor is not called if
the third parameter is a NULL pointer or the fourth parameter is negative.
(2) The special constant, <a href="#SQLITE_STATIC">SQLITE_STATIC</a>, may be passed to indicate that
the application remains responsible for disposing of the object. In this
case, the object and the provided pointer to it must remain valid until
either the prepared statement is finalized or the same SQL parameter is
bound to something else, whichever occurs sooner.
(3) The constant, <a href="#SQLITE_STATIC">SQLITE_TRANSIENT</a>, may be passed to indicate that the
object is to be copied prior to the return from sqlite3_bind_*(). The
object and pointer to it must remain valid until then. SQLite will then
manage the lifetime of its private copy.</p>
<p>The sixth argument to sqlite3_bind_text64() must be one of
<a href="#SQLITE_ANY">SQLITE_UTF8</a>, <a href="#SQLITE_ANY">SQLITE_UTF16</a>, <a href="#SQLITE_ANY">SQLITE_UTF16BE</a>, or <a href="#SQLITE_ANY">SQLITE_UTF16LE</a>
to specify the encoding of the text in the third parameter. If
the sixth argument to sqlite3_bind_text64() is not one of the
allowed values shown above, or if the text encoding is different
from the encoding specified by the sixth parameter, then the behavior
is undefined.</p>
<p>The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
is filled with zeroes. A zeroblob uses a fixed amount of memory
(just an integer to hold its size) while it is being processed.
Zeroblobs are intended to serve as placeholders for BLOBs whose
content is later written using
<a href="#sqlite3_blob_open">incremental BLOB I/O</a> routines.
A negative value for the zeroblob results in a zero-length BLOB.</p>
<p>The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
<a href="#sqlite3_stmt">prepared statement</a> S to have an SQL value of NULL, but to also be
associated with the pointer P of type T. D is either a NULL pointer or
a pointer to a destructor function for P. SQLite will invoke the
destructor D with a single argument of P when it is finished using
P. The T parameter should be a static string, preferably a string
literal. The sqlite3_bind_pointer() routine is part of the
<a href="bindptr.html">pointer passing interface</a> added for SQLite 3.20.0.</p>
<p>If any of the sqlite3_bind_*() routines are called with a NULL pointer
for the <a href="#sqlite3_stmt">prepared statement</a> or with a prepared statement for which
<a href="#sqlite3_step">sqlite3_step()</a> has been called more recently than <a href="#sqlite3_reset">sqlite3_reset()</a>,
then the call will return <a href="#SQLITE_ABORT">SQLITE_MISUSE</a>. If any sqlite3_bind_()
routine is passed a <a href="#sqlite3_stmt">prepared statement</a> that has been finalized, the
result is undefined and probably harmful.</p>
<p>Bindings are not cleared by the <a href="#sqlite3_reset">sqlite3_reset()</a> routine.
Unbound parameters are interpreted as NULL.</p>
<p>The sqlite3_bind_* routines return <a href="#SQLITE_ABORT">SQLITE_OK</a> on success or an
<a href="rescode.html">error code</a> if anything goes wrong.
<a href="#SQLITE_ABORT">SQLITE_TOOBIG</a> might be returned if the size of a string or BLOB
exceeds limits imposed by <a href="#sqlite3_limit">sqlite3_limit</a>(<a href="#sqlitelimitlength">SQLITE_LIMIT_LENGTH</a>) or
<a href="limits.html#max_length">SQLITE_MAX_LENGTH</a>.
<a href="#SQLITE_ABORT">SQLITE_RANGE</a> is returned if the parameter
index is out of range. <a href="#SQLITE_ABORT">SQLITE_NOMEM</a> is returned if malloc() fails.</p>
<p>See also: <a href="#sqlite3_bind_parameter_count">sqlite3_bind_parameter_count()</a>,
<a href="#sqlite3_bind_parameter_name">sqlite3_bind_parameter_name()</a>, and <a href="#sqlite3_bind_parameter_index">sqlite3_bind_parameter_index()</a>.
</p><hr><a name="sqlite3_prepare"></a>
<h2>Compiling An SQL Statement</h2>
</div>
<blockquote><pre>
int sqlite3_prepare(
sqlite3 *db, /* Database handle */
const char *zSql, /* SQL statement, UTF-8 encoded */
int nByte, /* Maximum length of zSql in bytes. */
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
const char **pzTail /* OUT: Pointer to unused portion of zSql */
);
int sqlite3_prepare_v2(
sqlite3 *db, /* Database handle */
const char *zSql, /* SQL statement, UTF-8 encoded */
int nByte, /* Maximum length of zSql in bytes. */
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
const char **pzTail /* OUT: Pointer to unused portion of zSql */
);
int sqlite3_prepare_v3(
sqlite3 *db, /* Database handle */
const char *zSql, /* SQL statement, UTF-8 encoded */
int nByte, /* Maximum length of zSql in bytes. */
unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
const char **pzTail /* OUT: Pointer to unused portion of zSql */
);
int sqlite3_prepare16(
sqlite3 *db, /* Database handle */
const void *zSql, /* SQL statement, UTF-16 encoded */
int nByte, /* Maximum length of zSql in bytes. */
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
const void **pzTail /* OUT: Pointer to unused portion of zSql */
);
int sqlite3_prepare16_v2(
sqlite3 *db, /* Database handle */
const void *zSql, /* SQL statement, UTF-16 encoded */
int nByte, /* Maximum length of zSql in bytes. */
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
const void **pzTail /* OUT: Pointer to unused portion of zSql */
);
int sqlite3_prepare16_v3(
sqlite3 *db, /* Database handle */
const void *zSql, /* SQL statement, UTF-16 encoded */
int nByte, /* Maximum length of zSql in bytes. */
unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
const void **pzTail /* OUT: Pointer to unused portion of zSql */
);
</pre></blockquote>
<p>
To execute an SQL statement, it must first be compiled into a byte-code
program using one of these routines. Or, in other words, these routines
are constructors for the <a href="#sqlite3_stmt">prepared statement</a> object.</p>
<p>The preferred routine to use is <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>. The
<a href="#sqlite3_prepare">sqlite3_prepare()</a> interface is legacy and should be avoided.
<a href="#sqlite3_prepare">sqlite3_prepare_v3()</a> has an extra "prepFlags" option that is used
for special purposes.</p>
<p>The use of the UTF-8 interfaces is preferred, as SQLite currently
does all parsing using UTF-8. The UTF-16 interfaces are provided
as a convenience. The UTF-16 interfaces work by converting the
input text into UTF-8, then invoking the corresponding UTF-8 interface.</p>
<p>The first argument, "db", is a <a href="#sqlite3">database connection</a> obtained from a
prior successful call to <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open_v2()</a> or
<a href="#sqlite3_open">sqlite3_open16()</a>. The database connection must not have been closed.</p>
<p>The second argument, "zSql", is the statement to be compiled, encoded
as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(),
and sqlite3_prepare_v3()
interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
and sqlite3_prepare16_v3() use UTF-16.</p>
<p>If the nByte argument is negative, then zSql is read up to the
first zero terminator. If nByte is positive, then it is the
number of bytes read from zSql. If nByte is zero, then no prepared
statement is generated.
If the caller knows that the supplied string is nul-terminated, then
there is a small performance advantage to passing an nByte parameter that
is the number of bytes in the input string <i>including</i>
the nul-terminator.</p>
<p>If pzTail is not NULL then *pzTail is made to point to the first byte
past the end of the first SQL statement in zSql. These routines only
compile the first statement in zSql, so *pzTail is left pointing to
what remains uncompiled.</p>
<p>*ppStmt is left pointing to a compiled <a href="#sqlite3_stmt">prepared statement</a> that can be
executed using <a href="#sqlite3_step">sqlite3_step()</a>. If there is an error, *ppStmt is set
to NULL. If the input text contains no SQL (if the input is an empty
string or a comment) then *ppStmt is set to NULL.
The calling procedure is responsible for deleting the compiled
SQL statement using <a href="#sqlite3_finalize">sqlite3_finalize()</a> after it has finished with it.
ppStmt may not be NULL.</p>
<p>On success, the sqlite3_prepare() family of routines return <a href="#SQLITE_ABORT">SQLITE_OK</a>;
otherwise an <a href="rescode.html">error code</a> is returned.</p>
<p>The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
are retained for backwards compatibility, but their use is discouraged.
In the "vX" interfaces, the prepared statement
that is returned (the <a href="#sqlite3_stmt">sqlite3_stmt</a> object) contains a copy of the
original SQL text. This causes the <a href="#sqlite3_step">sqlite3_step()</a> interface to
behave differently in three ways:</p>
<p><ol>
<li>
If the database schema changes, instead of returning <a href="#SQLITE_ABORT">SQLITE_SCHEMA</a> as it
always used to do, <a href="#sqlite3_step">sqlite3_step()</a> will automatically recompile the SQL
statement and try to run it again. As many as <a href="compile.html#max_schema_retry">SQLITE_MAX_SCHEMA_RETRY</a>
retries will occur before sqlite3_step() gives up and returns an error.
</li></p>
<p><li>
When an error occurs, <a href="#sqlite3_step">sqlite3_step()</a> will return one of the detailed
<a href="rescode.html">error codes</a> or <a href="rescode.html#extrc">extended error codes</a>. The legacy behavior was that
<a href="#sqlite3_step">sqlite3_step()</a> would only return a generic <a href="#SQLITE_ABORT">SQLITE_ERROR</a> result code
and the application would have to make a second call to <a href="#sqlite3_reset">sqlite3_reset()</a>
in order to find the underlying cause of the problem. With the "v2" prepare
interfaces, the underlying reason for the error is returned immediately.
</li></p>
<p><li>
If the specific value bound to a <a href="lang_expr.html#varparam">host parameter</a> in the
WHERE clause might influence the choice of query plan for a statement,
then the statement will be automatically recompiled, as if there had been
a schema change, on the first <a href="#sqlite3_step">sqlite3_step()</a> call following any change
to the <a href="#sqlite3_bind_blob">bindings</a> of that <a href="lang_expr.html#varparam">parameter</a>.
The specific value of a WHERE-clause <a href="lang_expr.html#varparam">parameter</a> might influence the
choice of query plan if the parameter is the left-hand side of a <a href="lang_expr.html#like">LIKE</a>
or <a href="lang_expr.html#glob">GLOB</a> operator or if the parameter is compared to an indexed column
and the <a href="compile.html#enable_stat4">SQLITE_ENABLE_STAT4</a> compile-time option is enabled.
</li>
</ol></p>
<p><p>sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
the extra prepFlags parameter, which is a bit array consisting of zero or
more of the <a href="#sqlitepreparepersistent">SQLITE_PREPARE_*</a> flags. The
sqlite3_prepare_v2() interface works exactly the same as
sqlite3_prepare_v3() with a zero prepFlags parameter.
</p><hr><a name="sqlite3_set_authorizer"></a>
<h2>Compile-Time Authorization Callbacks</h2>
</div>
<blockquote><pre>
int sqlite3_set_authorizer(
sqlite3*,
int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
void *pUserData
);
</pre></blockquote>
<p>
This routine registers an authorizer callback with a particular
<a href="#sqlite3">database connection</a>, supplied in the first argument.
The authorizer callback is invoked as SQL statements are being compiled
by <a href="#sqlite3_prepare">sqlite3_prepare()</a> or its variants <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>,
<a href="#sqlite3_prepare">sqlite3_prepare_v3()</a>, <a href="#sqlite3_prepare">sqlite3_prepare16()</a>, <a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a>,
and <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a>. At various
points during the compilation process, as logic is being created
to perform various actions, the authorizer callback is invoked to
see if those actions are allowed. The authorizer callback should
return <a href="#SQLITE_ABORT">SQLITE_OK</a> to allow the action, <a href="#SQLITE_DENY">SQLITE_IGNORE</a> to disallow the
specific action but allow the SQL statement to continue to be
compiled, or <a href="#SQLITE_DENY">SQLITE_DENY</a> to cause the entire SQL statement to be
rejected with an error. If the authorizer callback returns
any value other than <a href="#SQLITE_DENY">SQLITE_IGNORE</a>, <a href="#SQLITE_ABORT">SQLITE_OK</a>, or <a href="#SQLITE_DENY">SQLITE_DENY</a>
then the <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> or equivalent call that triggered
the authorizer will fail with an error message.</p>
<p>When the callback returns <a href="#SQLITE_ABORT">SQLITE_OK</a>, that means the operation
requested is ok. When the callback returns <a href="#SQLITE_DENY">SQLITE_DENY</a>, the
<a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> or equivalent call that triggered the
authorizer will fail with an error message explaining that
access is denied.</p>
<p>The first parameter to the authorizer callback is a copy of the third
parameter to the sqlite3_set_authorizer() interface. The second parameter
to the callback is an integer <a href="#SQLITE_ALTER_TABLE">action code</a> that specifies
the particular action to be authorized. The third through sixth parameters
to the callback are either NULL pointers or zero-terminated strings
that contain additional details about the action to be authorized.
Applications must always be prepared to encounter a NULL pointer in any
of the third through the sixth parameters of the authorization callback.</p>
<p>If the action code is <a href="#SQLITE_ALTER_TABLE">SQLITE_READ</a>
and the callback returns <a href="#SQLITE_DENY">SQLITE_IGNORE</a> then the
<a href="#sqlite3_stmt">prepared statement</a> statement is constructed to substitute
a NULL value in place of the table column that would have
been read if <a href="#SQLITE_ABORT">SQLITE_OK</a> had been returned. The <a href="#SQLITE_DENY">SQLITE_IGNORE</a>
return can be used to deny an untrusted user access to individual
columns of a table.
When a table is referenced by a <a href="lang_select.html">SELECT</a> but no column values are
extracted from that table (for example in a query like
"SELECT count(*) FROM tab") then the <a href="#SQLITE_ALTER_TABLE">SQLITE_READ</a> authorizer callback
is invoked once for that table with a column name that is an empty string.
If the action code is <a href="#SQLITE_ALTER_TABLE">SQLITE_DELETE</a> and the callback returns
<a href="#SQLITE_DENY">SQLITE_IGNORE</a> then the <a href="lang_delete.html">DELETE</a> operation proceeds but the
<a href="lang_delete.html#truncateopt">truncate optimization</a> is disabled and all rows are deleted individually.</p>
<p>An authorizer is used when <a href="#sqlite3_prepare">preparing</a>
SQL statements from an untrusted source, to ensure that the SQL statements
do not try to access data they are not allowed to see, or that they do not
try to execute malicious statements that damage the database. For
example, an application may allow a user to enter arbitrary
SQL queries for evaluation by a database. But the application does
not want the user to be able to make arbitrary changes to the
database. An authorizer could then be put in place while the
user-entered SQL is being <a href="#sqlite3_prepare">prepared</a> that
disallows everything except <a href="lang_select.html">SELECT</a> statements.</p>
<p>Applications that need to process SQL from untrusted sources
might also consider lowering resource limits using <a href="#sqlite3_limit">sqlite3_limit()</a>
and limiting database size using the <a href="pragma.html#pragma_max_page_count">max_page_count</a> <a href="pragma.html#syntax">PRAGMA</a>
in addition to using an authorizer.</p>
<p>Only a single authorizer can be in place on a database connection
at a time. Each call to sqlite3_set_authorizer overrides the
previous call. Disable the authorizer by installing a NULL callback.
The authorizer is disabled by default.</p>
<p>The authorizer callback must not do anything that will modify
the database connection that invoked the authorizer callback.
Note that <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> and <a href="#sqlite3_step">sqlite3_step()</a> both modify their
database connections for the meaning of "modify" in this paragraph.</p>
<p>When <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> is used to prepare a statement, the
statement might be re-prepared during <a href="#sqlite3_step">sqlite3_step()</a> due to a
schema change. Hence, the application should ensure that the
correct authorizer callback remains in place during the <a href="#sqlite3_step">sqlite3_step()</a>.</p>
<p>Note that the authorizer callback is invoked only during
<a href="#sqlite3_prepare">sqlite3_prepare()</a> or its variants. Authorization is not
performed during statement evaluation in <a href="#sqlite3_step">sqlite3_step()</a>, unless
as stated in the previous paragraph, sqlite3_step() invokes
sqlite3_prepare_v2() to reprepare a statement after a schema change.
</p><hr><a name="sqlite3_get_autocommit"></a>
<h2>Test For Auto-Commit Mode</h2>
</div>
<blockquote><pre>
int sqlite3_get_autocommit(sqlite3*);
</pre></blockquote>
<p>
The sqlite3_get_autocommit() interface returns non-zero or
zero if the given database connection is or is not in autocommit mode,
respectively. Autocommit mode is on by default.
Autocommit mode is disabled by a <a href="lang_transaction.html">BEGIN</a> statement.
Autocommit mode is re-enabled by a <a href="lang_transaction.html">COMMIT</a> or <a href="lang_transaction.html">ROLLBACK</a>.</p>
<p>If certain kinds of errors occur on a statement within a multi-statement
transaction (errors including <a href="#SQLITE_ABORT">SQLITE_FULL</a>, <a href="#SQLITE_ABORT">SQLITE_IOERR</a>,
<a href="#SQLITE_ABORT">SQLITE_NOMEM</a>, <a href="#SQLITE_ABORT">SQLITE_BUSY</a>, and <a href="#SQLITE_ABORT">SQLITE_INTERRUPT</a>) then the
transaction might be rolled back automatically. The only way to
find out whether SQLite automatically rolled back the transaction after
an error is to use this function.</p>
<p>If another thread changes the autocommit status of the database
connection while this routine is running, then the return value
is undefined.
</p><hr><a name="sqlite3_busy_handler"></a>
<h2>Register A Callback To Handle SQLITE_BUSY Errors</h2>
</div>
<blockquote><pre>
int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
</pre></blockquote>
<p>
The sqlite3_busy_handler(D,X,P) routine sets a callback function X
that might be invoked with argument P whenever
an attempt is made to access a database table associated with
<a href="#sqlite3">database connection</a> D when another thread
or process has the table locked.
The sqlite3_busy_handler() interface is used to implement
<a href="#sqlite3_busy_timeout">sqlite3_busy_timeout()</a> and <a href="pragma.html#pragma_busy_timeout">PRAGMA busy_timeout</a>.</p>
<p>If the busy callback is NULL, then <a href="#SQLITE_ABORT">SQLITE_BUSY</a>
is returned immediately upon encountering the lock. If the busy callback
is not NULL, then the callback might be invoked with two arguments.</p>
<p>The first argument to the busy handler is a copy of the void* pointer which
is the third argument to sqlite3_busy_handler(). The second argument to
the busy handler callback is the number of times that the busy handler has
been invoked previously for the same locking event. If the
busy callback returns 0, then no additional attempts are made to
access the database and <a href="#SQLITE_ABORT">SQLITE_BUSY</a> is returned
to the application.
If the callback returns non-zero, then another attempt
is made to access the database and the cycle repeats.</p>
<p>The presence of a busy handler does not guarantee that it will be invoked
when there is lock contention. If SQLite determines that invoking the busy
handler could result in a deadlock, it will go ahead and return <a href="#SQLITE_ABORT">SQLITE_BUSY</a>
to the application instead of invoking the
busy handler.
Consider a scenario where one process is holding a read lock that
it is trying to promote to a reserved lock and
a second process is holding a reserved lock that it is trying
to promote to an exclusive lock. The first process cannot proceed
because it is blocked by the second and the second process cannot
proceed because it is blocked by the first. If both processes
invoke the busy handlers, neither will make any progress. Therefore,
SQLite returns <a href="#SQLITE_ABORT">SQLITE_BUSY</a> for the first process, hoping that this
will induce the first process to release its read lock and allow
the second process to proceed.</p>
<p>The default busy callback is NULL.</p>
<p>There can only be a single busy handler defined for each
<a href="#sqlite3">database connection</a>. Setting a new busy handler clears any
previously set handler. Note that calling <a href="#sqlite3_busy_timeout">sqlite3_busy_timeout()</a>
or evaluating <a href="pragma.html#pragma_busy_timeout">PRAGMA busy_timeout=N</a> will change the
busy handler and thus clear any previously set busy handler.</p>
<p>The busy callback should not take any actions which modify the
database connection that invoked the busy handler. In other words,
the busy handler is not reentrant. Any such actions
result in undefined behavior.</p>
<p>A busy handler must not close the database connection
or <a href="#sqlite3_stmt">prepared statement</a> that invoked the busy handler.
</p><hr><a name="sqlite3_column_blob"></a>
<h2>Result Values From A Query</h2>
</div>
<blockquote><pre>
const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
double sqlite3_column_double(sqlite3_stmt*, int iCol);
int sqlite3_column_int(sqlite3_stmt*, int iCol);
sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
int sqlite3_column_type(sqlite3_stmt*, int iCol);
</pre></blockquote>
<p>
<b>Summary:</b>
<blockquote><table border=0 cellpadding=0 cellspacing=0>
<tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result
<tr><td><b>sqlite3_column_double</b><td>→<td>REAL result
<tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result
<tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result
<tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result
<tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result
<tr><td><b>sqlite3_column_value</b><td>→<td>The result as an
<a href="#sqlite3_value">unprotected sqlite3_value</a> object.
<tr><td> <td> <td>
<tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB
or a UTF-8 TEXT result in bytes
<tr><td><b>sqlite3_column_bytes16 </b>
<td>→ <td>Size of UTF-16
TEXT in bytes
<tr><td><b>sqlite3_column_type</b><td>→<td>Default
datatype of the result
</table></blockquote></p>
<p><b>Details:</b></p>
<p>These routines return information about a single column of the current
result row of a query. In every case the first argument is a pointer
to the <a href="#sqlite3_stmt">prepared statement</a> that is being evaluated (the <a href="#sqlite3_stmt">sqlite3_stmt*</a>
that was returned from <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> or one of its variants)
and the second argument is the index of the column for which information
should be returned. The leftmost column of the result set has the index 0.
The number of columns in the result can be determined using
<a href="#sqlite3_column_count">sqlite3_column_count()</a>.</p>
<p>If the SQL statement does not currently point to a valid row, or if the
column index is out of range, the result is undefined.
These routines may only be called when the most recent call to
<a href="#sqlite3_step">sqlite3_step()</a> has returned <a href="#SQLITE_ABORT">SQLITE_ROW</a> and neither
<a href="#sqlite3_reset">sqlite3_reset()</a> nor <a href="#sqlite3_finalize">sqlite3_finalize()</a> have been called subsequently.
If any of these routines are called after <a href="#sqlite3_reset">sqlite3_reset()</a> or
<a href="#sqlite3_finalize">sqlite3_finalize()</a> or after <a href="#sqlite3_step">sqlite3_step()</a> has returned
something other than <a href="#SQLITE_ABORT">SQLITE_ROW</a>, the results are undefined.
If <a href="#sqlite3_step">sqlite3_step()</a> or <a href="#sqlite3_reset">sqlite3_reset()</a> or <a href="#sqlite3_finalize">sqlite3_finalize()</a>
are called from a different thread while any of these routines
are pending, then the results are undefined.</p>
<p>The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
each return the value of a result column in a specific data format. If
the result column is not initially in the requested format (for example,
if the query returns an integer but the sqlite3_column_text() interface
is used to extract the value) then an automatic type conversion is performed.</p>
<p>The sqlite3_column_type() routine returns the
<a href="#SQLITE_BLOB">datatype code</a> for the initial data type
of the result column. The returned value is one of <a href="#SQLITE_BLOB">SQLITE_INTEGER</a>,
<a href="#SQLITE_BLOB">SQLITE_FLOAT</a>, <a href="#SQLITE_BLOB">SQLITE_TEXT</a>, <a href="#SQLITE_BLOB">SQLITE_BLOB</a>, or <a href="#SQLITE_BLOB">SQLITE_NULL</a>.
The return value of sqlite3_column_type() can be used to decide which
of the first six interface should be used to extract the column value.
The value returned by sqlite3_column_type() is only meaningful if no
automatic type conversions have occurred for the value in question.
After a type conversion, the result of calling sqlite3_column_type()
is undefined, though harmless. Future
versions of SQLite may change the behavior of sqlite3_column_type()
following a type conversion.</p>
<p>If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
or sqlite3_column_bytes16() interfaces can be used to determine the size
of that BLOB or string.</p>
<p>If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
routine returns the number of bytes in that BLOB or string.
If the result is a UTF-16 string, then sqlite3_column_bytes() converts
the string to UTF-8 and then returns the number of bytes.
If the result is a numeric value then sqlite3_column_bytes() uses
<a href="#sqlite3_mprintf">sqlite3_snprintf()</a> to convert that value to a UTF-8 string and returns
the number of bytes in that string.
If the result is NULL, then sqlite3_column_bytes() returns zero.</p>
<p>If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
routine returns the number of bytes in that BLOB or string.
If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
the string to UTF-16 and then returns the number of bytes.
If the result is a numeric value then sqlite3_column_bytes16() uses
<a href="#sqlite3_mprintf">sqlite3_snprintf()</a> to convert that value to a UTF-16 string and returns
the number of bytes in that string.
If the result is NULL, then sqlite3_column_bytes16() returns zero.</p>
<p>The values returned by <a href="#sqlite3_column_blob">sqlite3_column_bytes()</a> and
<a href="#sqlite3_column_blob">sqlite3_column_bytes16()</a> do not include the zero terminators at the end
of the string. For clarity: the values returned by
<a href="#sqlite3_column_blob">sqlite3_column_bytes()</a> and <a href="#sqlite3_column_blob">sqlite3_column_bytes16()</a> are the number of
bytes in the string, not the number of characters.</p>
<p>Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
even empty strings, are always zero-terminated. The return
value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.</p>
<p>Strings returned by sqlite3_column_text16() always have the endianness
which is native to the platform, regardless of the text encoding set
for the database.</p>
<p><b>Warning:</b> The object returned by <a href="#sqlite3_column_blob">sqlite3_column_value()</a> is an
<a href="#sqlite3_value">unprotected sqlite3_value</a> object. In a multithreaded environment,
an unprotected sqlite3_value object may only be used safely with
<a href="#sqlite3_bind_blob">sqlite3_bind_value()</a> and <a href="#sqlite3_result_blob">sqlite3_result_value()</a>.
If the <a href="#sqlite3_value">unprotected sqlite3_value</a> object returned by
<a href="#sqlite3_column_blob">sqlite3_column_value()</a> is used in any other way, including calls
to routines like <a href="#sqlite3_value_blob">sqlite3_value_int()</a>, <a href="#sqlite3_value_blob">sqlite3_value_text()</a>,
or <a href="#sqlite3_value_blob">sqlite3_value_bytes()</a>, the behavior is not threadsafe.
Hence, the sqlite3_column_value() interface
is normally only useful within the implementation of
<a href="appfunc.html">application-defined SQL functions</a> or <a href="vtab.html">virtual tables</a>, not within
top-level application code.</p>
<p>These routines may attempt to convert the datatype of the result.
For example, if the internal representation is FLOAT and a text result
is requested, <a href="#sqlite3_mprintf">sqlite3_snprintf()</a> is used internally to perform the
conversion automatically. The following table details the conversions
that are applied:</p>
<p><blockquote>
<table border="1">
<tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion</p>
<p><tr><td> NULL <td> INTEGER <td> Result is 0
<tr><td> NULL <td> FLOAT <td> Result is 0.0
<tr><td> NULL <td> TEXT <td> Result is a NULL pointer
<tr><td> NULL <td> BLOB <td> Result is a NULL pointer
<tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
<tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
<tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
<tr><td> FLOAT <td> INTEGER <td> <a href="lang_expr.html#castexpr">CAST</a> to INTEGER
<tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
<tr><td> FLOAT <td> BLOB <td> <a href="lang_expr.html#castexpr">CAST</a> to BLOB
<tr><td> TEXT <td> INTEGER <td> <a href="lang_expr.html#castexpr">CAST</a> to INTEGER
<tr><td> TEXT <td> FLOAT <td> <a href="lang_expr.html#castexpr">CAST</a> to REAL
<tr><td> TEXT <td> BLOB <td> No change
<tr><td> BLOB <td> INTEGER <td> <a href="lang_expr.html#castexpr">CAST</a> to INTEGER
<tr><td> BLOB <td> FLOAT <td> <a href="lang_expr.html#castexpr">CAST</a> to REAL
<tr><td> BLOB <td> TEXT <td> <a href="lang_expr.html#castexpr">CAST</a> to TEXT, ensure zero terminator
</table>
</blockquote></p>
<p>Note that when type conversions occur, pointers returned by prior
calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
sqlite3_column_text16() may be invalidated.
Type conversions and pointer invalidations might occur
in the following cases:</p>
<p><ul>
<li> The initial content is a BLOB and sqlite3_column_text() or
sqlite3_column_text16() is called. A zero-terminator might
need to be added to the string.</li>
<li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
sqlite3_column_text16() is called. The content must be converted
to UTF-16.</li>
<li> The initial content is UTF-16 text and sqlite3_column_bytes() or
sqlite3_column_text() is called. The content must be converted
to UTF-8.</li>
</ul></p>
<p>Conversions between UTF-16be and UTF-16le are always done in place and do
not invalidate a prior pointer, though of course the content of the buffer
that the prior pointer references will have been modified. Other kinds
of conversion are done in place when it is possible, but sometimes they
are not possible and in those cases prior pointers are invalidated.</p>
<p>The safest policy is to invoke these routines
in one of the following ways:</p>
<p><ul>
<li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
<li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
<li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
</ul></p>
<p>In other words, you should call sqlite3_column_text(),
sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
into the desired format, then invoke sqlite3_column_bytes() or
sqlite3_column_bytes16() to find the size of the result. Do not mix calls
to sqlite3_column_text() or sqlite3_column_blob() with calls to
sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
with calls to sqlite3_column_bytes().</p>
<p>The pointers returned are valid until a type conversion occurs as
described above, or until <a href="#sqlite3_step">sqlite3_step()</a> or <a href="#sqlite3_reset">sqlite3_reset()</a> or
<a href="#sqlite3_finalize">sqlite3_finalize()</a> is called. The memory space used to hold strings
and BLOBs is freed automatically. Do not pass the pointers returned
from <a href="#sqlite3_column_blob">sqlite3_column_blob()</a>, <a href="#sqlite3_column_blob">sqlite3_column_text()</a>, etc. into
<a href="#sqlite3_free">sqlite3_free()</a>.</p>
<p>As long as the input parameters are correct, these routines will only
fail if an out-of-memory error occurs during a format conversion.
Only the following subset of interfaces are subject to out-of-memory
errors:</p>
<p><ul>
<li> sqlite3_column_blob()
<li> sqlite3_column_text()
<li> sqlite3_column_text16()
<li> sqlite3_column_bytes()
<li> sqlite3_column_bytes16()
</ul></p>
<p>If an out-of-memory error occurs, then the return value from these
routines is the same as if the column had contained an SQL NULL value.
Valid SQL NULL returns can be distinguished from out-of-memory errors
by invoking the <a href="#sqlite3_errcode">sqlite3_errcode()</a> immediately after the suspect
return value is obtained and before any
other SQLite interface is called on the same <a href="#sqlite3">database connection</a>.
</p><hr><a name="sqlite3_file_control"></a>
<h2>Low-Level Control Of Database Files</h2>
</div>
<blockquote><pre>
int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
</pre></blockquote>
<p>
The <a href="#sqlite3_file_control">sqlite3_file_control()</a> interface makes a direct call to the
xFileControl method for the <a href="#sqlite3_io_methods">sqlite3_io_methods</a> object associated
with a particular database identified by the second argument. The
name of the database is "main" for the main database or "temp" for the
TEMP database, or the name that appears after the AS keyword for
databases that are added using the <a href="lang_attach.html">ATTACH</a> SQL command.
A NULL pointer can be used in place of "main" to refer to the
main database file.
The third and fourth parameters to this routine
are passed directly through to the second and third parameters of
the xFileControl method. The return value of the xFileControl
method becomes the return value of this routine.</p>
<p>A few opcodes for <a href="#sqlite3_file_control">sqlite3_file_control()</a> are handled directly
by the SQLite core and never invoke the
sqlite3_io_methods.xFileControl method.
The <a href="#sqlitefcntlfilepointer">SQLITE_FCNTL_FILE_POINTER</a> value for the op parameter causes
a pointer to the underlying <a href="#sqlite3_file">sqlite3_file</a> object to be written into
the space pointed to by the 4th parameter. The
<a href="#sqlitefcntljournalpointer">SQLITE_FCNTL_JOURNAL_POINTER</a> works similarly except that it returns
the <a href="#sqlite3_file">sqlite3_file</a> object associated with the journal file instead of
the main database. The <a href="#sqlitefcntlvfspointer">SQLITE_FCNTL_VFS_POINTER</a> opcode returns
a pointer to the underlying <a href="#sqlite3_vfs">sqlite3_vfs</a> object for the file.
The <a href="#sqlitefcntldataversion">SQLITE_FCNTL_DATA_VERSION</a> returns the data version counter
from the pager.</p>
<p>If the second parameter (zDbName) does not match the name of any
open database file, then SQLITE_ERROR is returned. This error
code is not remembered and will not be recalled by <a href="#sqlite3_errcode">sqlite3_errcode()</a>
or <a href="#sqlite3_errcode">sqlite3_errmsg()</a>. The underlying xFileControl method might
also return SQLITE_ERROR. There is no way to distinguish between
an incorrect zDbName and an SQLITE_ERROR return from the underlying
xFileControl method.</p>
<p>See also: <a href="#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE">file control opcodes</a>
</p><hr><a name="sqlite3_create_function"></a>
<h2>Create Or Redefine SQL Functions</h2>
</div>
<blockquote><pre>
int sqlite3_create_function(
sqlite3 *db,
const char *zFunctionName,
int nArg,
int eTextRep,
void *pApp,
void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
void (*xStep)(sqlite3_context*,int,sqlite3_value**),
void (*xFinal)(sqlite3_context*)
);
int sqlite3_create_function16(
sqlite3 *db,
const void *zFunctionName,
int nArg,
int eTextRep,
void *pApp,
void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
void (*xStep)(sqlite3_context*,int,sqlite3_value**),
void (*xFinal)(sqlite3_context*)
);
int sqlite3_create_function_v2(
sqlite3 *db,
const char *zFunctionName,
int nArg,
int eTextRep,
void *pApp,
void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
void (*xStep)(sqlite3_context*,int,sqlite3_value**),
void (*xFinal)(sqlite3_context*),
void(*xDestroy)(void*)
);
int sqlite3_create_window_function(
sqlite3 *db,
const char *zFunctionName,
int nArg,
int eTextRep,
void *pApp,
void (*xStep)(sqlite3_context*,int,sqlite3_value**),
void (*xFinal)(sqlite3_context*),
void (*xValue)(sqlite3_context*),
void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
void(*xDestroy)(void*)
);
</pre></blockquote>
<p>
These functions (collectively known as "function creation routines")
are used to add SQL functions or aggregates or to redefine the behavior
of existing SQL functions or aggregates. The only differences between
the three "sqlite3_create_function*" routines are the text encoding
expected for the second parameter (the name of the function being
created) and the presence or absence of a destructor callback for
the application data pointer. Function sqlite3_create_window_function()
is similar, but allows the user to supply the extra callback functions
needed by <a href="windowfunctions.html#aggwinfunc">aggregate window functions</a>.</p>
<p>The first parameter is the <a href="#sqlite3">database connection</a> to which the SQL
function is to be added. If an application uses more than one database
connection then application-defined SQL functions must be added
to each database connection separately.</p>
<p>The second parameter is the name of the SQL function to be created or
redefined. The length of the name is limited to 255 bytes in a UTF-8
representation, exclusive of the zero-terminator. Note that the name
length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
Any attempt to create a function with a longer name
will result in <a href="#SQLITE_ABORT">SQLITE_MISUSE</a> being returned.</p>
<p>The third parameter (nArg)
is the number of arguments that the SQL function or
aggregate takes. If this parameter is -1, then the SQL function or
aggregate may take any number of arguments between 0 and the limit
set by <a href="#sqlite3_limit">sqlite3_limit</a>(<a href="#sqlitelimitfunctionarg">SQLITE_LIMIT_FUNCTION_ARG</a>). If the third
parameter is less than -1 or greater than 127 then the behavior is
undefined.</p>
<p>The fourth parameter, eTextRep, specifies what
<a href="#SQLITE_ANY">text encoding</a> this SQL function prefers for
its parameters. The application should set this parameter to
<a href="#SQLITE_ANY">SQLITE_UTF16LE</a> if the function implementation invokes
<a href="#sqlite3_value_blob">sqlite3_value_text16le()</a> on an input, or <a href="#SQLITE_ANY">SQLITE_UTF16BE</a> if the
implementation invokes <a href="#sqlite3_value_blob">sqlite3_value_text16be()</a> on an input, or
<a href="#SQLITE_ANY">SQLITE_UTF16</a> if <a href="#sqlite3_value_blob">sqlite3_value_text16()</a> is used, or <a href="#SQLITE_ANY">SQLITE_UTF8</a>
otherwise. The same SQL function may be registered multiple times using
different preferred text encodings, with different implementations for
each encoding.
When multiple implementations of the same function are available, SQLite
will pick the one that involves the least amount of data conversion.</p>
<p>The fourth parameter may optionally be ORed with <a href="#sqlitedeterministic">SQLITE_DETERMINISTIC</a>
to signal that the function will always return the same result given
the same inputs within a single SQL statement. Most SQL functions are
deterministic. The built-in <a href="lang_corefunc.html#random">random()</a> SQL function is an example of a
function that is not deterministic. The SQLite query planner is able to
perform additional optimizations on deterministic functions, so use
of the <a href="#sqlitedeterministic">SQLITE_DETERMINISTIC</a> flag is recommended where possible.</p>
<p>The fourth parameter may also optionally include the <a href="#sqlitedirectonly">SQLITE_DIRECTONLY</a>
flag, which if present prevents the function from being invoked from
within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
index expressions, or the WHERE clause of partial indexes.</p>
<p>For best security, the <a href="#sqlitedirectonly">SQLITE_DIRECTONLY</a> flag is recommended for
all application-defined SQL functions that do not need to be
used inside of triggers, view, CHECK constraints, or other elements of
the database schema. This flags is especially recommended for SQL
functions that have side effects or reveal internal application state.
Without this flag, an attacker might be able to modify the schema of
a database file to include invocations of the function with parameters
chosen by the attacker, which the application will then execute when
the database file is opened and read.</p>
<p>The fifth parameter is an arbitrary pointer. The implementation of the
function can gain access to this pointer using <a href="#sqlite3_user_data">sqlite3_user_data()</a>.</p>
<p>The sixth, seventh and eighth parameters passed to the three
"sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
pointers to C-language functions that implement the SQL function or
aggregate. A scalar SQL function requires an implementation of the xFunc
callback only; NULL pointers must be passed as the xStep and xFinal
parameters. An aggregate SQL function requires an implementation of xStep
and xFinal and NULL pointer must be passed for xFunc. To delete an existing
SQL function or aggregate, pass NULL pointers for all three function
callbacks.</p>
<p>The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
and xInverse) passed to sqlite3_create_window_function are pointers to
C-language callbacks that implement the new function. xStep and xFinal
must both be non-NULL. xValue and xInverse may either both be NULL, in
which case a regular aggregate function is created, or must both be
non-NULL, in which case the new function may be used as either an aggregate
or aggregate window function. More details regarding the implementation
of aggregate window functions are
<a href="windowfunctions.html#udfwinfunc">available here</a>.</p>
<p>If the final parameter to sqlite3_create_function_v2() or
sqlite3_create_window_function() is not NULL, then it is destructor for
the application data pointer. The destructor is invoked when the function
is deleted, either by being overloaded or when the database connection
closes. The destructor is also invoked if the call to
sqlite3_create_function_v2() fails. When the destructor callback is
invoked, it is passed a single argument which is a copy of the application
data pointer which was the fifth parameter to sqlite3_create_function_v2().</p>
<p>It is permitted to register multiple implementations of the same
functions with the same name but with either differing numbers of
arguments or differing preferred text encodings. SQLite will use
the implementation that most closely matches the way in which the
SQL function is used. A function implementation with a non-negative
nArg parameter is a better match than a function implementation with
a negative nArg. A function where the preferred text encoding
matches the database encoding is a better
match than a function where the encoding is different.
A function where the encoding difference is between UTF16le and UTF16be
is a closer match than a function where the encoding difference is
between UTF8 and UTF16.</p>
<p>Built-in functions may be overloaded by new application-defined functions.</p>
<p>An application-defined function is permitted to call other
SQLite interfaces. However, such calls must not
close the database connection nor finalize or reset the prepared
statement in which the function is running.
</p><hr>
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