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diff --git a/www/c3ref/value.html b/www/c3ref/value.html new file mode 100644 index 0000000..7344677 --- /dev/null +++ b/www/c3ref/value.html @@ -0,0 +1,193 @@ +<!DOCTYPE html> +<html><head> +<meta name="viewport" content="width=device-width, initial-scale=1.0"> +<meta http-equiv="content-type" content="text/html; charset=UTF-8"> +<link href="../sqlite.css" rel="stylesheet"> +<title>Dynamically Typed Value Object</title> +<!-- path=../ --> +</head> +<body> +<div class=nosearch> +<a href="../index.html"> +<img class="logo" src="../images/sqlite370_banner.gif" alt="SQLite" border="0"> +</a> +<div><!-- IE hack to prevent disappearing logo --></div> +<div class="tagline desktoponly"> +Small. Fast. 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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="../c3ref/value_dup.html">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="../c3ref/threadsafe.html">sqlite3_threadsafe()</a> returning 0) +or if SQLite is run in one of reduced mutex modes +<a href="../c3ref/c_config_covering_index_scan.html#sqliteconfigsinglethread">SQLITE_CONFIG_SINGLETHREAD</a> or <a href="../c3ref/c_config_covering_index_scan.html#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="../c3ref/vtab_rhs_value.html">sqlite3_vtab_rhs_value()</a> +are protected. +The sqlite3_value object returned by +<a href="../c3ref/column_blob.html">sqlite3_column_value()</a> is unprotected. +Unprotected sqlite3_value objects may only be used as arguments +to <a href="../c3ref/result_blob.html">sqlite3_result_value()</a>, <a href="../c3ref/bind_blob.html">sqlite3_bind_value()</a>, and +<a href="../c3ref/value_dup.html">sqlite3_value_dup()</a>. +The <a href="../c3ref/value_blob.html">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='../c3ref/value_blob.html'>sqlite3_value_blob</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_bytes</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_bytes16</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_double</a></li> +<li><a href='../c3ref/value_dup.html'>sqlite3_value_dup</a></li> +<li><a href='../c3ref/value_encoding.html'>sqlite3_value_encoding</a></li> +<li><a href='../c3ref/value_dup.html'>sqlite3_value_free</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_frombind</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_int</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_int64</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_nochange</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_numeric_type</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_pointer</a></li> +<li><a href='../c3ref/value_subtype.html'>sqlite3_value_subtype</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_text</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_text16</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_text16be</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_text16le</a></li> +<li><a href='../c3ref/value_blob.html'>sqlite3_value_type</a></li> +</ul> +</div> +</p> +<p>See also lists of + <a href="../c3ref/objlist.html">Objects</a>, + <a href="../c3ref/constlist.html">Constants</a>, and + <a href="../c3ref/funclist.html">Functions</a>.</p> + |