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+
+<chapter id="ecpg">
+ <title><application>ECPG</application> &mdash; Embedded <acronym>SQL</acronym> in C</title>
+
+ <indexterm zone="ecpg"><primary>embedded SQL</primary><secondary>in C</secondary></indexterm>
+ <indexterm zone="ecpg"><primary>C</primary></indexterm>
+ <indexterm zone="ecpg"><primary>ECPG</primary></indexterm>
+
+ <para>
+  This chapter describes the embedded <acronym>SQL</acronym> package
+  for <productname>PostgreSQL</productname>. It was written by
+  Linus Tolke (<email>linus@epact.se</email>) and Michael Meskes
+  (<email>meskes@postgresql.org</email>). Originally it was written to work with
+  <acronym>C</acronym>. It also works with <acronym>C++</acronym>, but
+  it does not recognize all <acronym>C++</acronym> constructs yet.
+ </para>
+
+ <para>
+  This documentation is quite incomplete.  But since this
+  interface is standardized, additional information can be found in
+  many resources about SQL.
+ </para>
+
+ <sect1 id="ecpg-concept">
+  <title>The Concept</title>
+
+  <para>
+   An embedded SQL program consists of code written in an ordinary
+   programming language, in this case C, mixed with SQL commands in
+   specially marked sections.  To build the program, the source code (<filename>*.pgc</filename>)
+   is first passed through the embedded SQL preprocessor, which converts it
+   to an ordinary C program (<filename>*.c</filename>), and afterwards it can be processed by a C
+   compiler.  (For details about the compiling and linking see <xref linkend="ecpg-process"/>.)
+   Converted ECPG applications call functions in the libpq library
+   through the embedded SQL library (ecpglib), and communicate with
+   the PostgreSQL server using the normal frontend-backend protocol.
+  </para>
+
+  <para>
+   Embedded <acronym>SQL</acronym> has advantages over other methods
+   for handling <acronym>SQL</acronym> commands from C code. First, it
+   takes care of the tedious passing of information to and from
+   variables in your <acronym>C</acronym> program.  Second, the SQL
+   code in the program is checked at build time for syntactical
+   correctness.  Third, embedded <acronym>SQL</acronym> in C is
+   specified in the <acronym>SQL</acronym> standard and supported by
+   many other <acronym>SQL</acronym> database systems.  The
+   <productname>PostgreSQL</productname> implementation is designed to match this
+   standard as much as possible, and it is usually possible to port
+   embedded <acronym>SQL</acronym> programs written for other SQL
+   databases to <productname>PostgreSQL</productname> with relative
+   ease.
+  </para>
+
+  <para>
+   As already stated, programs written for the embedded
+   <acronym>SQL</acronym> interface are normal C programs with special
+   code inserted to perform database-related actions.  This special
+   code always has the form:
+<programlisting>
+EXEC SQL ...;
+</programlisting>
+   These statements syntactically take the place of a C statement.
+   Depending on the particular statement, they can appear at the
+   global level or within a function.
+  </para>
+
+  <para>
+   Embedded
+   <acronym>SQL</acronym> statements follow the case-sensitivity rules of
+   normal <acronym>SQL</acronym> code, and not those of C. Also they allow nested
+   C-style comments as per the SQL standard. The C part of the
+   program, however, follows the C standard of not accepting nested comments.
+   Embedded <acronym>SQL</acronym> statements likewise use SQL rules, not
+   C rules, for parsing quoted strings and identifiers.
+   (See <xref linkend="sql-syntax-strings"/> and
+   <xref linkend="sql-syntax-identifiers"/> respectively.  Note that
+   ECPG assumes that <varname>standard_conforming_strings</varname>
+   is <literal>on</literal>.)
+   Of course, the C part of the program follows C quoting rules.
+  </para>
+
+  <para>
+   The following sections explain all the embedded SQL statements.
+  </para>
+ </sect1>
+
+ <sect1 id="ecpg-connect">
+  <title>Managing Database Connections</title>
+
+  <para>
+   This section describes how to open, close, and switch database
+   connections.
+  </para>
+
+  <sect2 id="ecpg-connecting">
+   <title>Connecting to the Database Server</title>
+
+  <para>
+   One connects to a database using the following statement:
+<programlisting>
+EXEC SQL CONNECT TO <replaceable>target</replaceable> <optional>AS <replaceable>connection-name</replaceable></optional> <optional>USER <replaceable>user-name</replaceable></optional>;
+</programlisting>
+   The <replaceable>target</replaceable> can be specified in the
+   following ways:
+
+   <itemizedlist>
+    <listitem>
+     <simpara>
+      <literal><replaceable>dbname</replaceable><optional>@<replaceable>hostname</replaceable></optional><optional>:<replaceable>port</replaceable></optional></literal>
+     </simpara>
+    </listitem>
+
+    <listitem>
+     <simpara>
+      <literal>tcp:postgresql://<replaceable>hostname</replaceable><optional>:<replaceable>port</replaceable></optional><optional>/<replaceable>dbname</replaceable></optional><optional>?<replaceable>options</replaceable></optional></literal>
+     </simpara>
+    </listitem>
+
+    <listitem>
+     <simpara>
+      <literal>unix:postgresql://localhost<optional>:<replaceable>port</replaceable></optional><optional>/<replaceable>dbname</replaceable></optional><optional>?<replaceable>options</replaceable></optional></literal>
+     </simpara>
+    </listitem>
+
+    <listitem>
+     <simpara>
+      an SQL string literal containing one of the above forms
+     </simpara>
+    </listitem>
+
+    <listitem>
+     <simpara>
+      a reference to a character variable containing one of the above forms (see examples)
+     </simpara>
+    </listitem>
+
+    <listitem>
+     <simpara>
+      <literal>DEFAULT</literal>
+     </simpara>
+    </listitem>
+   </itemizedlist>
+
+   The connection target <literal>DEFAULT</literal> initiates a connection
+   to the default database under the default user name.  No separate
+   user name or connection name can be specified in that case.
+  </para>
+
+  <para>
+   If you specify the connection target directly (that is, not as a string
+   literal or variable reference), then the components of the target are
+   passed through normal SQL parsing; this means that, for example,
+   the <replaceable>hostname</replaceable> must look like one or more SQL
+   identifiers separated by dots, and those identifiers will be
+   case-folded unless double-quoted.  Values of
+   any <replaceable>options</replaceable> must be SQL identifiers,
+   integers, or variable references.  Of course, you can put nearly
+   anything into an SQL identifier by double-quoting it.
+   In practice, it is probably less error-prone to use a (single-quoted)
+   string literal or a variable reference than to write the connection
+   target directly.
+  </para>
+
+  <para>
+   There are also different ways to specify the user name:
+
+   <itemizedlist>
+    <listitem>
+     <simpara>
+      <literal><replaceable>username</replaceable></literal>
+     </simpara>
+    </listitem>
+
+    <listitem>
+     <simpara>
+      <literal><replaceable>username</replaceable>/<replaceable>password</replaceable></literal>
+     </simpara>
+    </listitem>
+
+    <listitem>
+     <simpara>
+      <literal><replaceable>username</replaceable> IDENTIFIED BY <replaceable>password</replaceable></literal>
+     </simpara>
+    </listitem>
+
+    <listitem>
+     <simpara>
+      <literal><replaceable>username</replaceable> USING <replaceable>password</replaceable></literal>
+     </simpara>
+    </listitem>
+   </itemizedlist>
+
+   As above, the parameters <replaceable>username</replaceable> and
+   <replaceable>password</replaceable> can be an SQL identifier, an
+   SQL string literal, or a reference to a character variable.
+  </para>
+
+  <para>
+   If the connection target includes any <replaceable>options</replaceable>,
+   those consist of
+   <literal><replaceable>keyword</replaceable>=<replaceable>value</replaceable></literal>
+   specifications separated by ampersands (<literal>&amp;</literal>).
+   The allowed key words are the same ones recognized
+   by <application>libpq</application> (see
+   <xref linkend="libpq-paramkeywords"/>).  Spaces are ignored before
+   any <replaceable>keyword</replaceable> or <replaceable>value</replaceable>,
+   though not within or after one.  Note that there is no way to
+   write <literal>&amp;</literal> within a <replaceable>value</replaceable>.
+  </para>
+
+  <para>
+   Notice that when specifying a socket connection
+   (with the <literal>unix:</literal> prefix), the host name must be
+   exactly <literal>localhost</literal>.  To select a non-default
+   socket directory, write the directory's pathname as the value of
+   a <varname>host</varname> option in
+   the <replaceable>options</replaceable> part of the target.
+  </para>
+
+  <para>
+   The <replaceable>connection-name</replaceable> is used to handle
+   multiple connections in one program.  It can be omitted if a
+   program uses only one connection.  The most recently opened
+   connection becomes the current connection, which is used by default
+   when an SQL statement is to be executed (see later in this
+   chapter).
+  </para>
+
+  <para>
+   Here are some examples of <command>CONNECT</command> statements:
+<programlisting>
+EXEC SQL CONNECT TO mydb@sql.mydomain.com;
+
+EXEC SQL CONNECT TO tcp:postgresql://sql.mydomain.com/mydb AS myconnection USER john;
+
+EXEC SQL BEGIN DECLARE SECTION;
+const char *target = "mydb@sql.mydomain.com";
+const char *user = "john";
+const char *passwd = "secret";
+EXEC SQL END DECLARE SECTION;
+ ...
+EXEC SQL CONNECT TO :target USER :user USING :passwd;
+/* or EXEC SQL CONNECT TO :target USER :user/:passwd; */
+</programlisting>
+   The last example makes use of the feature referred to above as
+   character variable references.  You will see in later sections how C
+   variables can be used in SQL statements when you prefix them with a
+   colon.
+  </para>
+
+  <para>
+   Be advised that the format of the connection target is not
+   specified in the SQL standard.  So if you want to develop portable
+   applications, you might want to use something based on the last
+   example above to encapsulate the connection target string
+   somewhere.
+  </para>
+
+  <para>
+   If untrusted users have access to a database that has not adopted a
+   <link linkend="ddl-schemas-patterns">secure schema usage pattern</link>,
+   begin each session by removing publicly-writable schemas
+   from <varname>search_path</varname>.  For example,
+   add <literal>options=-c search_path=</literal>
+   to <literal><replaceable>options</replaceable></literal>, or
+   issue <literal>EXEC SQL SELECT pg_catalog.set_config('search_path', '',
+   false);</literal> after connecting.  This consideration is not specific to
+   ECPG; it applies to every interface for executing arbitrary SQL commands.
+  </para>
+  </sect2>
+
+  <sect2 id="ecpg-set-connection">
+   <title>Choosing a Connection</title>
+
+  <para>
+   SQL statements in embedded SQL programs are by default executed on
+   the current connection, that is, the most recently opened one.  If
+   an application needs to manage multiple connections, then there are
+   three ways to handle this.
+  </para>
+
+  <para>
+   The first option is to explicitly choose a connection for each SQL
+   statement, for example:
+<programlisting>
+EXEC SQL AT <replaceable>connection-name</replaceable> SELECT ...;
+</programlisting>
+   This option is particularly suitable if the application needs to
+   use several connections in mixed order.
+  </para>
+
+  <para>
+   If your application uses multiple threads of execution, they cannot share a
+   connection concurrently. You must either explicitly control access to the connection
+   (using mutexes) or use a connection for each thread.
+  </para>
+
+  <para>
+   The second option is to execute a statement to switch the current
+   connection.  That statement is:
+<programlisting>
+EXEC SQL SET CONNECTION <replaceable>connection-name</replaceable>;
+</programlisting>
+   This option is particularly convenient if many statements are to be
+   executed on the same connection.
+  </para>
+
+  <para>
+   Here is an example program managing multiple database connections:
+<programlisting><![CDATA[
+#include <stdio.h>
+
+EXEC SQL BEGIN DECLARE SECTION;
+    char dbname[1024];
+EXEC SQL END DECLARE SECTION;
+
+int
+main()
+{
+    EXEC SQL CONNECT TO testdb1 AS con1 USER testuser;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+    EXEC SQL CONNECT TO testdb2 AS con2 USER testuser;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+    EXEC SQL CONNECT TO testdb3 AS con3 USER testuser;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+
+    /* This query would be executed in the last opened database "testdb3". */
+    EXEC SQL SELECT current_database() INTO :dbname;
+    printf("current=%s (should be testdb3)\n", dbname);
+
+    /* Using "AT" to run a query in "testdb2" */
+    EXEC SQL AT con2 SELECT current_database() INTO :dbname;
+    printf("current=%s (should be testdb2)\n", dbname);
+
+    /* Switch the current connection to "testdb1". */
+    EXEC SQL SET CONNECTION con1;
+
+    EXEC SQL SELECT current_database() INTO :dbname;
+    printf("current=%s (should be testdb1)\n", dbname);
+
+    EXEC SQL DISCONNECT ALL;
+    return 0;
+}
+]]></programlisting>
+
+   This example would produce this output:
+<screen>
+current=testdb3 (should be testdb3)
+current=testdb2 (should be testdb2)
+current=testdb1 (should be testdb1)
+</screen>
+  </para>
+
+  <para>
+  The third option is to declare an SQL identifier linked to
+  the connection, for example:
+<programlisting>
+EXEC SQL AT <replaceable>connection-name</replaceable> DECLARE <replaceable>statement-name</replaceable> STATEMENT;
+EXEC SQL PREPARE <replaceable>statement-name</replaceable> FROM :<replaceable>dyn-string</replaceable>;
+</programlisting>
+   Once you link an SQL identifier to a connection, you execute dynamic SQL
+   without an AT clause. Note that this option behaves like preprocessor
+   directives, therefore the link is enabled only in the file.
+  </para>
+  <para>
+   Here is an example program using this option:
+<programlisting><![CDATA[
+#include <stdio.h>
+
+EXEC SQL BEGIN DECLARE SECTION;
+char dbname[128];
+char *dyn_sql = "SELECT current_database()";
+EXEC SQL END DECLARE SECTION;
+
+int main(){
+  EXEC SQL CONNECT TO postgres AS con1;
+  EXEC SQL CONNECT TO testdb AS con2;
+  EXEC SQL AT con1 DECLARE stmt STATEMENT;
+  EXEC SQL PREPARE stmt FROM :dyn_sql;
+  EXEC SQL EXECUTE stmt INTO :dbname;
+  printf("%s\n", dbname);
+
+  EXEC SQL DISCONNECT ALL;
+  return 0;
+}
+]]></programlisting>
+
+   This example would produce this output, even if the default connection is testdb:
+<screen>
+postgres
+</screen>
+  </para>
+  </sect2>
+
+  <sect2 id="ecpg-disconnect">
+   <title>Closing a Connection</title>
+
+  <para>
+   To close a connection, use the following statement:
+<programlisting>
+EXEC SQL DISCONNECT <optional><replaceable>connection</replaceable></optional>;
+</programlisting>
+   The <replaceable>connection</replaceable> can be specified
+   in the following ways:
+
+   <itemizedlist>
+    <listitem>
+     <simpara>
+      <literal><replaceable>connection-name</replaceable></literal>
+     </simpara>
+    </listitem>
+
+    <listitem>
+     <simpara>
+      <literal>CURRENT</literal>
+     </simpara>
+    </listitem>
+
+    <listitem>
+     <simpara>
+      <literal>ALL</literal>
+     </simpara>
+    </listitem>
+   </itemizedlist>
+
+   If no connection name is specified, the current connection is
+   closed.
+  </para>
+
+  <para>
+   It is good style that an application always explicitly disconnect
+   from every connection it opened.
+  </para>
+  </sect2>
+
+ </sect1>
+
+ <sect1 id="ecpg-commands">
+  <title>Running SQL Commands</title>
+
+  <para>
+   Any SQL command can be run from within an embedded SQL application.
+   Below are some examples of how to do that.
+  </para>
+
+  <sect2 id="ecpg-executing">
+   <title>Executing SQL Statements</title>
+
+  <para>
+   Creating a table:
+<programlisting>
+EXEC SQL CREATE TABLE foo (number integer, ascii char(16));
+EXEC SQL CREATE UNIQUE INDEX num1 ON foo(number);
+EXEC SQL COMMIT;
+</programlisting>
+  </para>
+
+  <para>
+   Inserting rows:
+<programlisting>
+EXEC SQL INSERT INTO foo (number, ascii) VALUES (9999, 'doodad');
+EXEC SQL COMMIT;
+</programlisting>
+  </para>
+
+  <para>
+   Deleting rows:
+<programlisting>
+EXEC SQL DELETE FROM foo WHERE number = 9999;
+EXEC SQL COMMIT;
+</programlisting>
+  </para>
+
+  <para>
+   Updates:
+<programlisting>
+EXEC SQL UPDATE foo
+    SET ascii = 'foobar'
+    WHERE number = 9999;
+EXEC SQL COMMIT;
+</programlisting>
+  </para>
+
+  <para>
+   <literal>SELECT</literal> statements that return a single result
+   row can also be executed using
+   <literal>EXEC SQL</literal> directly.  To handle result sets with
+   multiple rows, an application has to use a cursor;
+   see <xref linkend="ecpg-cursors"/> below.  (As a special case, an
+   application can fetch multiple rows at once into an array host
+   variable; see <xref linkend="ecpg-variables-arrays"/>.)
+  </para>
+
+  <para>
+   Single-row select:
+<programlisting>
+EXEC SQL SELECT foo INTO :FooBar FROM table1 WHERE ascii = 'doodad';
+</programlisting>
+  </para>
+
+  <para>
+   Also, a configuration parameter can be retrieved with the
+   <literal>SHOW</literal> command:
+<programlisting>
+EXEC SQL SHOW search_path INTO :var;
+</programlisting>
+  </para>
+
+  <para>
+   The tokens of the form
+   <literal>:<replaceable>something</replaceable></literal> are
+   <firstterm>host variables</firstterm>, that is, they refer to
+   variables in the C program.  They are explained in <xref
+   linkend="ecpg-variables"/>.
+  </para>
+  </sect2>
+
+  <sect2 id="ecpg-cursors">
+   <title>Using Cursors</title>
+
+  <para>
+   To retrieve a result set holding multiple rows, an application has
+   to declare a cursor and fetch each row from the cursor.  The steps
+   to use a cursor are the following: declare a cursor, open it, fetch
+   a row from the cursor, repeat, and finally close it.
+  </para>
+
+  <para>
+   Select using cursors:
+<programlisting>
+EXEC SQL DECLARE foo_bar CURSOR FOR
+    SELECT number, ascii FROM foo
+    ORDER BY ascii;
+EXEC SQL OPEN foo_bar;
+EXEC SQL FETCH foo_bar INTO :FooBar, DooDad;
+...
+EXEC SQL CLOSE foo_bar;
+EXEC SQL COMMIT;
+</programlisting>
+  </para>
+
+  <para>
+   For more details about declaring a cursor, see <xref
+   linkend="ecpg-sql-declare"/>; for more details about fetching rows from a
+   cursor, see <xref linkend="sql-fetch"/>.
+  </para>
+
+   <note>
+    <para>
+     The ECPG <command>DECLARE</command> command does not actually
+     cause a statement to be sent to the PostgreSQL backend.  The
+     cursor is opened in the backend (using the
+     backend's <command>DECLARE</command> command) at the point when
+     the <command>OPEN</command> command is executed.
+    </para>
+   </note>
+  </sect2>
+
+  <sect2 id="ecpg-transactions">
+   <title>Managing Transactions</title>
+
+  <para>
+   In the default mode, statements are committed only when
+   <command>EXEC SQL COMMIT</command> is issued. The embedded SQL
+   interface also supports autocommit of transactions (similar to
+   <application>psql</application>'s default behavior) via the <option>-t</option>
+   command-line option to <command>ecpg</command> (see <xref
+   linkend="app-ecpg"/>) or via the <literal>EXEC SQL SET AUTOCOMMIT TO
+   ON</literal> statement. In autocommit mode, each command is
+   automatically committed unless it is inside an explicit transaction
+   block. This mode can be explicitly turned off using <literal>EXEC
+   SQL SET AUTOCOMMIT TO OFF</literal>.
+  </para>
+
+   <para>
+    The following transaction management commands are available:
+
+    <variablelist>
+     <varlistentry id="ecpg-transactions-exec-sql-commit">
+      <term><literal>EXEC SQL COMMIT</literal></term>
+      <listitem>
+       <para>
+        Commit an in-progress transaction.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-transactions-exec-sql-rollback">
+      <term><literal>EXEC SQL ROLLBACK</literal></term>
+      <listitem>
+       <para>
+        Roll back an in-progress transaction.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-transactions-exec-sql-prepare-transaction">
+      <term><literal>EXEC SQL PREPARE TRANSACTION </literal><replaceable class="parameter">transaction_id</replaceable></term>
+      <listitem>
+       <para>
+        Prepare the current transaction for two-phase commit.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-transactions-exec-sql-commit-prepared">
+      <term><literal>EXEC SQL COMMIT PREPARED </literal><replaceable class="parameter">transaction_id</replaceable></term>
+      <listitem>
+       <para>
+        Commit a transaction that is in prepared state.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-transactions-exec-sql-rollback-prepared">
+      <term><literal>EXEC SQL ROLLBACK PREPARED </literal><replaceable class="parameter">transaction_id</replaceable></term>
+      <listitem>
+       <para>
+        Roll back a transaction that is in prepared state.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-transactions-exec-sql-autocommit-on">
+      <term><literal>EXEC SQL SET AUTOCOMMIT TO ON</literal></term>
+      <listitem>
+       <para>
+        Enable autocommit mode.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-transactions-exec-sql-autocommit-off">
+      <term><literal>EXEC SQL SET AUTOCOMMIT TO OFF</literal></term>
+      <listitem>
+       <para>
+        Disable autocommit mode.  This is the default.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-prepared">
+   <title>Prepared Statements</title>
+
+   <para>
+    When the values to be passed to an SQL statement are not known at
+    compile time, or the same statement is going to be used many
+    times, then prepared statements can be useful.
+   </para>
+
+   <para>
+    The statement is prepared using the
+    command <literal>PREPARE</literal>.  For the values that are not
+    known yet, use the
+    placeholder <quote><literal>?</literal></quote>:
+<programlisting>
+EXEC SQL PREPARE stmt1 FROM "SELECT oid, datname FROM pg_database WHERE oid = ?";
+</programlisting>
+   </para>
+
+   <para>
+    If a statement returns a single row, the application can
+    call <literal>EXECUTE</literal> after
+    <literal>PREPARE</literal> to execute the statement, supplying the
+    actual values for the placeholders with a <literal>USING</literal>
+    clause:
+<programlisting>
+EXEC SQL EXECUTE stmt1 INTO :dboid, :dbname USING 1;
+</programlisting>
+   </para>
+
+   <para>
+    If a statement returns multiple rows, the application can use a
+    cursor declared based on the prepared statement.  To bind input
+    parameters, the cursor must be opened with
+    a <literal>USING</literal> clause:
+<programlisting>
+EXEC SQL PREPARE stmt1 FROM "SELECT oid,datname FROM pg_database WHERE oid &gt; ?";
+EXEC SQL DECLARE foo_bar CURSOR FOR stmt1;
+
+/* when end of result set reached, break out of while loop */
+EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+EXEC SQL OPEN foo_bar USING 100;
+...
+while (1)
+{
+    EXEC SQL FETCH NEXT FROM foo_bar INTO :dboid, :dbname;
+    ...
+}
+EXEC SQL CLOSE foo_bar;
+</programlisting>
+   </para>
+
+   <para>
+    When you don't need the prepared statement anymore, you should
+    deallocate it:
+<programlisting>
+EXEC SQL DEALLOCATE PREPARE <replaceable>name</replaceable>;
+</programlisting>
+   </para>
+
+   <para>
+    For more details about <literal>PREPARE</literal>,
+    see <xref linkend="ecpg-sql-prepare"/>. Also
+    see <xref linkend="ecpg-dynamic"/> for more details about using
+    placeholders and input parameters.
+   </para>
+  </sect2>
+ </sect1>
+
+ <sect1 id="ecpg-variables">
+  <title>Using Host Variables</title>
+
+  <para>
+   In <xref linkend="ecpg-commands"/> you saw how you can execute SQL
+   statements from an embedded SQL program.  Some of those statements
+   only used fixed values and did not provide a way to insert
+   user-supplied values into statements or have the program process
+   the values returned by the query.  Those kinds of statements are
+   not really useful in real applications.  This section explains in
+   detail how you can pass data between your C program and the
+   embedded SQL statements using a simple mechanism called
+   <firstterm>host variables</firstterm>. In an embedded SQL program we
+   consider the SQL statements to be <firstterm>guests</firstterm> in the C
+   program code which is the <firstterm>host language</firstterm>. Therefore
+   the variables of the C program are called <firstterm>host
+   variables</firstterm>.
+  </para>
+
+  <para>
+   Another way to exchange values between PostgreSQL backends and ECPG
+   applications is the use of SQL descriptors, described
+   in <xref linkend="ecpg-descriptors"/>.
+  </para>
+
+  <sect2 id="ecpg-variables-overview">
+   <title>Overview</title>
+
+   <para>
+    Passing data between the C program and the SQL statements is
+    particularly simple in embedded SQL.  Instead of having the
+    program paste the data into the statement, which entails various
+    complications, such as properly quoting the value, you can simply
+    write the name of a C variable into the SQL statement, prefixed by
+    a colon.  For example:
+<programlisting>
+EXEC SQL INSERT INTO sometable VALUES (:v1, 'foo', :v2);
+</programlisting>
+    This statement refers to two C variables named
+    <varname>v1</varname> and <varname>v2</varname> and also uses a
+    regular SQL string literal, to illustrate that you are not
+    restricted to use one kind of data or the other.
+   </para>
+
+   <para>
+    This style of inserting C variables in SQL statements works
+    anywhere a value expression is expected in an SQL statement.
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-declare-sections">
+   <title>Declare Sections</title>
+
+   <para>
+    To pass data from the program to the database, for example as
+    parameters in a query, or to pass data from the database back to
+    the program, the C variables that are intended to contain this
+    data need to be declared in specially marked sections, so the
+    embedded SQL preprocessor is made aware of them.
+   </para>
+
+   <para>
+    This section starts with:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+</programlisting>
+    and ends with:
+<programlisting>
+EXEC SQL END DECLARE SECTION;
+</programlisting>
+    Between those lines, there must be normal C variable declarations,
+    such as:
+<programlisting>
+int   x = 4;
+char  foo[16], bar[16];
+</programlisting>
+    As you can see, you can optionally assign an initial value to the variable.
+    The variable's scope is determined by the location of its declaring
+    section within the program.
+    You can also declare variables with the following syntax which implicitly
+    creates a declare section:
+<programlisting>
+EXEC SQL int i = 4;
+</programlisting>
+    You can have as many declare sections in a program as you like.
+   </para>
+
+   <para>
+    The declarations are also echoed to the output file as normal C
+    variables, so there's no need to declare them again.  Variables
+    that are not intended to be used in SQL commands can be declared
+    normally outside these special sections.
+   </para>
+
+   <para>
+    The definition of a structure or union also must be listed inside
+    a <literal>DECLARE</literal> section. Otherwise the preprocessor cannot
+    handle these types since it does not know the definition.
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-retrieving">
+   <title>Retrieving Query Results</title>
+
+   <para>
+    Now you should be able to pass data generated by your program into
+    an SQL command.  But how do you retrieve the results of a query?
+    For that purpose, embedded SQL provides special variants of the
+    usual commands <command>SELECT</command> and
+    <command>FETCH</command>.  These commands have a special
+    <literal>INTO</literal> clause that specifies which host variables
+    the retrieved values are to be stored in.
+    <command>SELECT</command> is used for a query that returns only
+    single row, and <command>FETCH</command> is used for a query that
+    returns multiple rows, using a cursor.
+   </para>
+
+   <para>
+    Here is an example:
+<programlisting>
+/*
+ * assume this table:
+ * CREATE TABLE test1 (a int, b varchar(50));
+ */
+
+EXEC SQL BEGIN DECLARE SECTION;
+int v1;
+VARCHAR v2;
+EXEC SQL END DECLARE SECTION;
+
+ ...
+
+EXEC SQL SELECT a, b INTO :v1, :v2 FROM test;
+</programlisting>
+    So the <literal>INTO</literal> clause appears between the select
+    list and the <literal>FROM</literal> clause.  The number of
+    elements in the select list and the list after
+    <literal>INTO</literal> (also called the target list) must be
+    equal.
+   </para>
+
+   <para>
+    Here is an example using the command <command>FETCH</command>:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+int v1;
+VARCHAR v2;
+EXEC SQL END DECLARE SECTION;
+
+ ...
+
+EXEC SQL DECLARE foo CURSOR FOR SELECT a, b FROM test;
+
+ ...
+
+do
+{
+    ...
+    EXEC SQL FETCH NEXT FROM foo INTO :v1, :v2;
+    ...
+} while (...);
+</programlisting>
+    Here the <literal>INTO</literal> clause appears after all the
+    normal clauses.
+   </para>
+
+  </sect2>
+
+  <sect2 id="ecpg-variables-type-mapping">
+   <title>Type Mapping</title>
+
+   <para>
+    When ECPG applications exchange values between the PostgreSQL
+    server and the C application, such as when retrieving query
+    results from the server or executing SQL statements with input
+    parameters, the values need to be converted between PostgreSQL
+    data types and host language variable types (C language data
+    types, concretely).  One of the main points of ECPG is that it
+    takes care of this automatically in most cases.
+   </para>
+
+   <para>
+    In this respect, there are two kinds of data types: Some simple
+    PostgreSQL data types, such as <type>integer</type>
+    and <type>text</type>, can be read and written by the application
+    directly.  Other PostgreSQL data types, such
+    as <type>timestamp</type> and <type>numeric</type> can only be
+    accessed through special library functions; see
+    <xref linkend="ecpg-special-types"/>.
+   </para>
+
+   <para>
+    <xref linkend="ecpg-datatype-hostvars-table"/> shows which PostgreSQL
+    data types correspond to which C data types.  When you wish to
+    send or receive a value of a given PostgreSQL data type, you
+    should declare a C variable of the corresponding C data type in
+    the declare section.
+   </para>
+
+   <table id="ecpg-datatype-hostvars-table">
+    <title>Mapping Between PostgreSQL Data Types and C Variable Types</title>
+    <tgroup cols="2">
+     <thead>
+      <row>
+       <entry>PostgreSQL data type</entry>
+       <entry>Host variable type</entry>
+      </row>
+     </thead>
+
+     <tbody>
+      <row>
+       <entry><type>smallint</type></entry>
+       <entry><type>short</type></entry>
+      </row>
+
+      <row>
+       <entry><type>integer</type></entry>
+       <entry><type>int</type></entry>
+      </row>
+
+      <row>
+       <entry><type>bigint</type></entry>
+       <entry><type>long long int</type></entry>
+      </row>
+
+      <row>
+       <entry><type>decimal</type></entry>
+       <entry><type>decimal</type><footnote id="ecpg-datatype-table-fn"><para>This type can only be accessed through special library functions; see <xref linkend="ecpg-special-types"/>.</para></footnote></entry>
+      </row>
+
+      <row>
+       <entry><type>numeric</type></entry>
+       <entry><type>numeric</type><footnoteref linkend="ecpg-datatype-table-fn"/></entry>
+      </row>
+
+      <row>
+       <entry><type>real</type></entry>
+       <entry><type>float</type></entry>
+      </row>
+
+      <row>
+       <entry><type>double precision</type></entry>
+       <entry><type>double</type></entry>
+      </row>
+
+      <row>
+       <entry><type>smallserial</type></entry>
+       <entry><type>short</type></entry>
+      </row>
+
+      <row>
+       <entry><type>serial</type></entry>
+       <entry><type>int</type></entry>
+      </row>
+
+      <row>
+       <entry><type>bigserial</type></entry>
+       <entry><type>long long int</type></entry>
+      </row>
+
+      <row>
+       <entry><type>oid</type></entry>
+       <entry><type>unsigned int</type></entry>
+      </row>
+
+      <row>
+       <entry><type>character(<replaceable>n</replaceable>)</type>, <type>varchar(<replaceable>n</replaceable>)</type>, <type>text</type></entry>
+       <entry><type>char[<replaceable>n</replaceable>+1]</type>, <type>VARCHAR[<replaceable>n</replaceable>+1]</type></entry>
+      </row>
+
+      <row>
+       <entry><type>name</type></entry>
+       <entry><type>char[NAMEDATALEN]</type></entry>
+      </row>
+
+      <row>
+       <entry><type>timestamp</type></entry>
+       <entry><type>timestamp</type><footnoteref linkend="ecpg-datatype-table-fn"/></entry>
+      </row>
+
+      <row>
+       <entry><type>interval</type></entry>
+       <entry><type>interval</type><footnoteref linkend="ecpg-datatype-table-fn"/></entry>
+      </row>
+
+      <row>
+       <entry><type>date</type></entry>
+       <entry><type>date</type><footnoteref linkend="ecpg-datatype-table-fn"/></entry>
+      </row>
+
+      <row>
+       <entry><type>boolean</type></entry>
+       <entry><type>bool</type><footnote><para>declared in <filename>ecpglib.h</filename> if not native</para></footnote></entry>
+      </row>
+
+      <row>
+       <entry><type>bytea</type></entry>
+       <entry><type>char *</type>, <type>bytea[<replaceable>n</replaceable>]</type></entry>
+      </row>
+     </tbody>
+    </tgroup>
+   </table>
+
+   <sect3 id="ecpg-char">
+    <title>Handling Character Strings</title>
+
+    <para>
+     To handle SQL character string data types, such
+     as <type>varchar</type> and <type>text</type>, there are two
+     possible ways to declare the host variables.
+    </para>
+
+    <para>
+     One way is using <type>char[]</type>, an array
+     of <type>char</type>, which is the most common way to handle
+     character data in C.
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+    char str[50];
+EXEC SQL END DECLARE SECTION;
+</programlisting>
+     Note that you have to take care of the length yourself.  If you
+     use this host variable as the target variable of a query which
+     returns a string with more than 49 characters, a buffer overflow
+     occurs.
+    </para>
+
+    <para>
+     The other way is using the <type>VARCHAR</type> type, which is a
+     special type provided by ECPG.  The definition on an array of
+     type <type>VARCHAR</type> is converted into a
+     named <type>struct</type> for every variable. A declaration like:
+<programlisting>
+VARCHAR var[180];
+</programlisting>
+     is converted into:
+<programlisting>
+struct varchar_var { int len; char arr[180]; } var;
+</programlisting>
+     The member <structfield>arr</structfield> hosts the string
+     including a terminating zero byte.  Thus, to store a string in
+     a <type>VARCHAR</type> host variable, the host variable has to be
+     declared with the length including the zero byte terminator.  The
+     member <structfield>len</structfield> holds the length of the
+     string stored in the <structfield>arr</structfield> without the
+     terminating zero byte.  When a host variable is used as input for
+     a query, if <literal>strlen(arr)</literal>
+     and <structfield>len</structfield> are different, the shorter one
+     is used.
+    </para>
+
+    <para>
+     <type>VARCHAR</type> can be written in upper or lower case, but
+     not in mixed case.
+    </para>
+
+    <para>
+     <type>char</type> and <type>VARCHAR</type> host variables can
+     also hold values of other SQL types, which will be stored in
+     their string forms.
+    </para>
+   </sect3>
+
+   <sect3 id="ecpg-special-types">
+    <title>Accessing Special Data Types</title>
+
+    <para>
+     ECPG contains some special types that help you to interact easily
+     with some special data types from the PostgreSQL server. In
+     particular, it has implemented support for the
+     <type>numeric</type>, <type>decimal</type>, <type>date</type>, <type>timestamp</type>,
+     and <type>interval</type> types.  These data types cannot usefully be
+     mapped to primitive host variable types (such
+     as <type>int</type>, <type>long long int</type>,
+     or <type>char[]</type>), because they have a complex internal
+     structure.  Applications deal with these types by declaring host
+     variables in special types and accessing them using functions in
+     the pgtypes library.  The pgtypes library, described in detail
+     in <xref linkend="ecpg-pgtypes"/> contains basic functions to deal
+     with those types, such that you do not need to send a query to
+     the SQL server just for adding an interval to a time stamp for
+     example.
+    </para>
+
+    <para>
+     The follow subsections describe these special data types. For
+     more details about pgtypes library functions,
+     see <xref linkend="ecpg-pgtypes"/>.
+    </para>
+
+    <sect4 id="ecpg-special-types-timestamp-date">
+     <title>timestamp, date</title>
+
+     <para>
+      Here is a pattern for handling <type>timestamp</type> variables
+      in the ECPG host application.
+     </para>
+
+     <para>
+      First, the program has to include the header file for the
+      <type>timestamp</type> type:
+<programlisting>
+#include &lt;pgtypes_timestamp.h>
+</programlisting>
+     </para>
+
+     <para>
+      Next, declare a host variable as type <type>timestamp</type> in
+      the declare section:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+timestamp ts;
+EXEC SQL END DECLARE SECTION;
+</programlisting>
+     </para>
+
+     <para>
+      And after reading a value into the host variable, process it
+      using pgtypes library functions. In following example, the
+      <type>timestamp</type> value is converted into text (ASCII) form
+      with the <function>PGTYPEStimestamp_to_asc()</function>
+      function:
+<programlisting>
+EXEC SQL SELECT now()::timestamp INTO :ts;
+
+printf("ts = %s\n", PGTYPEStimestamp_to_asc(ts));
+</programlisting>
+      This example will show some result like following:
+<screen>
+ts = 2010-06-27 18:03:56.949343
+</screen>
+     </para>
+
+     <para>
+      In addition, the DATE type can be handled in the same way. The
+      program has to include <filename>pgtypes_date.h</filename>, declare a host variable
+      as the date type and convert a DATE value into a text form using
+      <function>PGTYPESdate_to_asc()</function> function. For more details about the
+      pgtypes library functions, see <xref linkend="ecpg-pgtypes"/>.
+     </para>
+    </sect4>
+
+    <sect4 id="ecpg-type-interval">
+     <title>interval</title>
+
+     <para>
+      The handling of the <type>interval</type> type is also similar
+      to the <type>timestamp</type> and <type>date</type> types.  It
+      is required, however, to allocate memory for
+      an <type>interval</type> type value explicitly.  In other words,
+      the memory space for the variable has to be allocated in the
+      heap memory, not in the stack memory.
+     </para>
+
+     <para>
+      Here is an example program:
+<programlisting>
+#include &lt;stdio.h>
+#include &lt;stdlib.h>
+#include &lt;pgtypes_interval.h>
+
+int
+main(void)
+{
+EXEC SQL BEGIN DECLARE SECTION;
+    interval *in;
+EXEC SQL END DECLARE SECTION;
+
+    EXEC SQL CONNECT TO testdb;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+
+    in = PGTYPESinterval_new();
+    EXEC SQL SELECT '1 min'::interval INTO :in;
+    printf("interval = %s\n", PGTYPESinterval_to_asc(in));
+    PGTYPESinterval_free(in);
+
+    EXEC SQL COMMIT;
+    EXEC SQL DISCONNECT ALL;
+    return 0;
+}
+</programlisting>
+     </para>
+    </sect4>
+
+    <sect4 id="ecpg-type-numeric-decimal">
+     <title>numeric, decimal</title>
+
+     <para>
+      The handling of the <type>numeric</type>
+      and <type>decimal</type> types is similar to the
+      <type>interval</type> type: It requires defining a pointer,
+      allocating some memory space on the heap, and accessing the
+      variable using the pgtypes library functions.  For more details
+      about the pgtypes library functions,
+      see <xref linkend="ecpg-pgtypes"/>.
+     </para>
+
+     <para>
+      No functions are provided specifically for
+      the <type>decimal</type> type.  An application has to convert it
+      to a <type>numeric</type> variable using a pgtypes library
+      function to do further processing.
+     </para>
+
+     <para>
+      Here is an example program handling <type>numeric</type>
+      and <type>decimal</type> type variables.
+<programlisting>
+#include &lt;stdio.h>
+#include &lt;stdlib.h>
+#include &lt;pgtypes_numeric.h>
+
+EXEC SQL WHENEVER SQLERROR STOP;
+
+int
+main(void)
+{
+EXEC SQL BEGIN DECLARE SECTION;
+    numeric *num;
+    numeric *num2;
+    decimal *dec;
+EXEC SQL END DECLARE SECTION;
+
+    EXEC SQL CONNECT TO testdb;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+
+    num = PGTYPESnumeric_new();
+    dec = PGTYPESdecimal_new();
+
+    EXEC SQL SELECT 12.345::numeric(4,2), 23.456::decimal(4,2) INTO :num, :dec;
+
+    printf("numeric = %s\n", PGTYPESnumeric_to_asc(num, 0));
+    printf("numeric = %s\n", PGTYPESnumeric_to_asc(num, 1));
+    printf("numeric = %s\n", PGTYPESnumeric_to_asc(num, 2));
+
+    /* Convert decimal to numeric to show a decimal value. */
+    num2 = PGTYPESnumeric_new();
+    PGTYPESnumeric_from_decimal(dec, num2);
+
+    printf("decimal = %s\n", PGTYPESnumeric_to_asc(num2, 0));
+    printf("decimal = %s\n", PGTYPESnumeric_to_asc(num2, 1));
+    printf("decimal = %s\n", PGTYPESnumeric_to_asc(num2, 2));
+
+    PGTYPESnumeric_free(num2);
+    PGTYPESdecimal_free(dec);
+    PGTYPESnumeric_free(num);
+
+    EXEC SQL COMMIT;
+    EXEC SQL DISCONNECT ALL;
+    return 0;
+}
+</programlisting>
+     </para>
+    </sect4>
+
+    <sect4 id="ecpg-special-types-bytea">
+     <title>bytea</title>
+
+     <para>
+      The handling of the <type>bytea</type> type is similar to
+      that of <type>VARCHAR</type>. The definition on an array of type
+      <type>bytea</type> is converted into a named struct for every
+      variable. A declaration like:
+<programlisting>
+bytea var[180];
+</programlisting>
+     is converted into:
+<programlisting>
+struct bytea_var { int len; char arr[180]; } var;
+</programlisting>
+      The member <structfield>arr</structfield> hosts binary format
+      data. It can also handle <literal>'\0'</literal> as part of
+      data, unlike <type>VARCHAR</type>.
+      The data is converted from/to hex format and sent/received by
+      ecpglib.
+     </para>
+
+     <note>
+      <para>
+       <type>bytea</type> variable can be used only when
+       <xref linkend="guc-bytea-output"/> is set to <literal>hex</literal>.
+      </para>
+     </note>
+    </sect4>
+   </sect3>
+
+   <sect3 id="ecpg-variables-nonprimitive-c">
+    <title>Host Variables with Nonprimitive Types</title>
+
+    <para>
+     As a host variable you can also use arrays, typedefs, structs, and
+     pointers.
+    </para>
+
+    <sect4 id="ecpg-variables-arrays">
+     <title>Arrays</title>
+
+     <para>
+      There are two use cases for arrays as host variables.  The first
+      is a way to store some text string in <type>char[]</type>
+      or <type>VARCHAR[]</type>, as
+      explained in <xref linkend="ecpg-char"/>.  The second use case is to
+      retrieve multiple rows from a query result without using a
+      cursor.  Without an array, to process a query result consisting
+      of multiple rows, it is required to use a cursor and
+      the <command>FETCH</command> command.  But with array host
+      variables, multiple rows can be received at once.  The length of
+      the array has to be defined to be able to accommodate all rows,
+      otherwise a buffer overflow will likely occur.
+     </para>
+
+     <para>
+      Following example scans the <literal>pg_database</literal>
+      system table and shows all OIDs and names of the available
+      databases:
+<programlisting>
+int
+main(void)
+{
+EXEC SQL BEGIN DECLARE SECTION;
+    int dbid[8];
+    char dbname[8][16];
+    int i;
+EXEC SQL END DECLARE SECTION;
+
+    memset(dbname, 0, sizeof(char)* 16 * 8);
+    memset(dbid, 0, sizeof(int) * 8);
+
+    EXEC SQL CONNECT TO testdb;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+
+    /* Retrieve multiple rows into arrays at once. */
+    EXEC SQL SELECT oid,datname INTO :dbid, :dbname FROM pg_database;
+
+    for (i = 0; i &lt; 8; i++)
+        printf("oid=%d, dbname=%s\n", dbid[i], dbname[i]);
+
+    EXEC SQL COMMIT;
+    EXEC SQL DISCONNECT ALL;
+    return 0;
+}
+</programlisting>
+
+    This example shows following result. (The exact values depend on
+    local circumstances.)
+<screen>
+oid=1, dbname=template1
+oid=11510, dbname=template0
+oid=11511, dbname=postgres
+oid=313780, dbname=testdb
+oid=0, dbname=
+oid=0, dbname=
+oid=0, dbname=
+</screen>
+     </para>
+    </sect4>
+
+    <sect4 id="ecpg-variables-struct">
+     <title>Structures</title>
+
+     <para>
+      A structure whose member names match the column names of a query
+      result, can be used to retrieve multiple columns at once.  The
+      structure enables handling multiple column values in a single
+      host variable.
+     </para>
+
+     <para>
+      The following example retrieves OIDs, names, and sizes of the
+      available databases from the <literal>pg_database</literal>
+      system table and using
+      the <function>pg_database_size()</function> function.  In this
+      example, a structure variable <varname>dbinfo_t</varname> with
+      members whose names match each column in
+      the <literal>SELECT</literal> result is used to retrieve one
+      result row without putting multiple host variables in
+      the <literal>FETCH</literal> statement.
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+    typedef struct
+    {
+       int oid;
+       char datname[65];
+       long long int size;
+    } dbinfo_t;
+
+    dbinfo_t dbval;
+EXEC SQL END DECLARE SECTION;
+
+    memset(&amp;dbval, 0, sizeof(dbinfo_t));
+
+    EXEC SQL DECLARE cur1 CURSOR FOR SELECT oid, datname, pg_database_size(oid) AS size FROM pg_database;
+    EXEC SQL OPEN cur1;
+
+    /* when end of result set reached, break out of while loop */
+    EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+    while (1)
+    {
+        /* Fetch multiple columns into one structure. */
+        EXEC SQL FETCH FROM cur1 INTO :dbval;
+
+        /* Print members of the structure. */
+        printf("oid=%d, datname=%s, size=%lld\n", dbval.oid, dbval.datname, dbval.size);
+    }
+
+    EXEC SQL CLOSE cur1;
+</programlisting>
+     </para>
+
+     <para>
+      This example shows following result. (The exact values depend on
+      local circumstances.)
+<screen>
+oid=1, datname=template1, size=4324580
+oid=11510, datname=template0, size=4243460
+oid=11511, datname=postgres, size=4324580
+oid=313780, datname=testdb, size=8183012
+</screen>
+     </para>
+
+     <para>
+      Structure host variables <quote>absorb</quote> as many columns
+      as the structure as fields.  Additional columns can be assigned
+      to other host variables. For example, the above program could
+      also be restructured like this, with the <varname>size</varname>
+      variable outside the structure:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+    typedef struct
+    {
+       int oid;
+       char datname[65];
+    } dbinfo_t;
+
+    dbinfo_t dbval;
+    long long int size;
+EXEC SQL END DECLARE SECTION;
+
+    memset(&amp;dbval, 0, sizeof(dbinfo_t));
+
+    EXEC SQL DECLARE cur1 CURSOR FOR SELECT oid, datname, pg_database_size(oid) AS size FROM pg_database;
+    EXEC SQL OPEN cur1;
+
+    /* when end of result set reached, break out of while loop */
+    EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+    while (1)
+    {
+        /* Fetch multiple columns into one structure. */
+        EXEC SQL FETCH FROM cur1 INTO :dbval, :size;
+
+        /* Print members of the structure. */
+        printf("oid=%d, datname=%s, size=%lld\n", dbval.oid, dbval.datname, size);
+    }
+
+    EXEC SQL CLOSE cur1;
+</programlisting>
+     </para>
+    </sect4>
+
+    <sect4 id="ecpg-variables-nonprimitive-c-typedefs">
+     <title>Typedefs</title>
+     <indexterm>
+      <primary>typedef</primary>
+      <secondary>in ECPG</secondary>
+     </indexterm>
+
+     <para>
+      Use the <literal>typedef</literal> keyword to map new types to already
+      existing types.
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+    typedef char mychartype[40];
+    typedef long serial_t;
+EXEC SQL END DECLARE SECTION;
+</programlisting>
+      Note that you could also use:
+<programlisting>
+EXEC SQL TYPE serial_t IS long;
+</programlisting>
+      This declaration does not need to be part of a declare section;
+      that is, you can also write typedefs as normal C statements.
+     </para>
+
+     <para>
+      Any word you declare as a typedef cannot be used as an SQL keyword
+      in <literal>EXEC SQL</literal> commands later in the same program.
+      For example, this won't work:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+    typedef int start;
+EXEC SQL END DECLARE SECTION;
+...
+EXEC SQL START TRANSACTION;
+</programlisting>
+      ECPG will report a syntax error for <literal>START
+      TRANSACTION</literal>, because it no longer
+      recognizes <literal>START</literal> as an SQL keyword,
+      only as a typedef.
+      (If you have such a conflict, and renaming the typedef
+      seems impractical, you could write the SQL command
+      using <link linkend="ecpg-dynamic">dynamic SQL</link>.)
+     </para>
+
+     <note>
+      <para>
+       In <productname>PostgreSQL</productname> releases before v16, use
+       of SQL keywords as typedef names was likely to result in syntax
+       errors associated with use of the typedef itself, rather than use
+       of the name as an SQL keyword.  The new behavior is less likely to
+       cause problems when an existing ECPG application is recompiled in
+       a new <productname>PostgreSQL</productname> release with new
+       keywords.
+      </para>
+     </note>
+    </sect4>
+
+    <sect4 id="ecpg-variables-nonprimitive-c-pointers">
+     <title>Pointers</title>
+
+     <para>
+      You can declare pointers to the most common types. Note however
+      that you cannot use pointers as target variables of queries
+      without auto-allocation. See <xref linkend="ecpg-descriptors"/>
+      for more information on auto-allocation.
+     </para>
+
+     <para>
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+    int   *intp;
+    char **charp;
+EXEC SQL END DECLARE SECTION;
+</programlisting>
+     </para>
+    </sect4>
+   </sect3>
+  </sect2>
+
+  <sect2 id="ecpg-variables-nonprimitive-sql">
+   <title>Handling Nonprimitive SQL Data Types</title>
+
+   <para>
+    This section contains information on how to handle nonscalar and
+    user-defined SQL-level data types in ECPG applications.  Note that
+    this is distinct from the handling of host variables of
+    nonprimitive types, described in the previous section.
+   </para>
+
+   <sect3 id="ecpg-variables-nonprimitive-sql-arrays">
+    <title>Arrays</title>
+
+    <para>
+     Multi-dimensional SQL-level arrays are not directly supported in ECPG.
+     One-dimensional SQL-level arrays can be mapped into C array host
+     variables and vice-versa.  However, when creating a statement ecpg does
+     not know the types of the columns, so that it cannot check if a C array
+     is input into a corresponding SQL-level array.  When processing the
+     output of an SQL statement, ecpg has the necessary information and thus
+     checks if both are arrays.
+    </para>
+
+    <para>
+     If a query accesses <emphasis>elements</emphasis> of an array
+     separately, then this avoids the use of arrays in ECPG.  Then, a
+     host variable with a type that can be mapped to the element type
+     should be used.  For example, if a column type is array of
+     <type>integer</type>, a host variable of type <type>int</type>
+     can be used.  Also if the element type is <type>varchar</type>
+     or <type>text</type>, a host variable of type <type>char[]</type>
+     or <type>VARCHAR[]</type> can be used.
+    </para>
+
+    <para>
+     Here is an example.  Assume the following table:
+<programlisting>
+CREATE TABLE t3 (
+    ii integer[]
+);
+
+testdb=&gt; SELECT * FROM t3;
+     ii
+-------------
+ {1,2,3,4,5}
+(1 row)
+</programlisting>
+
+     The following example program retrieves the 4th element of the
+     array and stores it into a host variable of
+     type <type>int</type>:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+int ii;
+EXEC SQL END DECLARE SECTION;
+
+EXEC SQL DECLARE cur1 CURSOR FOR SELECT ii[4] FROM t3;
+EXEC SQL OPEN cur1;
+
+EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+while (1)
+{
+    EXEC SQL FETCH FROM cur1 INTO :ii ;
+    printf("ii=%d\n", ii);
+}
+
+EXEC SQL CLOSE cur1;
+</programlisting>
+
+     This example shows the following result:
+<screen>
+ii=4
+</screen>
+    </para>
+
+    <para>
+     To map multiple array elements to the multiple elements in an
+     array type host variables each element of array column and each
+     element of the host variable array have to be managed separately,
+     for example:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+int ii_a[8];
+EXEC SQL END DECLARE SECTION;
+
+EXEC SQL DECLARE cur1 CURSOR FOR SELECT ii[1], ii[2], ii[3], ii[4] FROM t3;
+EXEC SQL OPEN cur1;
+
+EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+while (1)
+{
+    EXEC SQL FETCH FROM cur1 INTO :ii_a[0], :ii_a[1], :ii_a[2], :ii_a[3];
+    ...
+}
+</programlisting>
+    </para>
+
+    <para>
+     Note again that
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+int ii_a[8];
+EXEC SQL END DECLARE SECTION;
+
+EXEC SQL DECLARE cur1 CURSOR FOR SELECT ii FROM t3;
+EXEC SQL OPEN cur1;
+
+EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+while (1)
+{
+    /* WRONG */
+    EXEC SQL FETCH FROM cur1 INTO :ii_a;
+    ...
+}
+</programlisting>
+     would not work correctly in this case, because you cannot map an
+     array type column to an array host variable directly.
+    </para>
+
+    <para>
+     Another workaround is to store arrays in their external string
+     representation in host variables of type <type>char[]</type>
+     or <type>VARCHAR[]</type>.  For more details about this
+     representation, see <xref linkend="arrays-input"/>.  Note that
+     this means that the array cannot be accessed naturally as an
+     array in the host program (without further processing that parses
+     the text representation).
+    </para>
+   </sect3>
+
+   <sect3 id="ecpg-variables-nonprimitive-sql-composite">
+    <title>Composite Types</title>
+
+    <para>
+     Composite types are not directly supported in ECPG, but an easy workaround is possible.
+  The
+     available workarounds are similar to the ones described for
+     arrays above: Either access each attribute separately or use the
+     external string representation.
+    </para>
+
+    <para>
+     For the following examples, assume the following type and table:
+<programlisting>
+CREATE TYPE comp_t AS (intval integer, textval varchar(32));
+CREATE TABLE t4 (compval comp_t);
+INSERT INTO t4 VALUES ( (256, 'PostgreSQL') );
+</programlisting>
+
+     The most obvious solution is to access each attribute separately.
+     The following program retrieves data from the example table by
+     selecting each attribute of the type <type>comp_t</type>
+     separately:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+int intval;
+varchar textval[33];
+EXEC SQL END DECLARE SECTION;
+
+/* Put each element of the composite type column in the SELECT list. */
+EXEC SQL DECLARE cur1 CURSOR FOR SELECT (compval).intval, (compval).textval FROM t4;
+EXEC SQL OPEN cur1;
+
+EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+while (1)
+{
+    /* Fetch each element of the composite type column into host variables. */
+    EXEC SQL FETCH FROM cur1 INTO :intval, :textval;
+
+    printf("intval=%d, textval=%s\n", intval, textval.arr);
+}
+
+EXEC SQL CLOSE cur1;
+</programlisting>
+    </para>
+
+    <para>
+     To enhance this example, the host variables to store values in
+     the <command>FETCH</command> command can be gathered into one
+     structure.  For more details about the host variable in the
+     structure form, see <xref linkend="ecpg-variables-struct"/>.
+     To switch to the structure, the example can be modified as below.
+     The two host variables, <varname>intval</varname>
+     and <varname>textval</varname>, become members of
+     the <structname>comp_t</structname> structure, and the structure
+     is specified on the <command>FETCH</command> command.
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+typedef struct
+{
+    int intval;
+    varchar textval[33];
+} comp_t;
+
+comp_t compval;
+EXEC SQL END DECLARE SECTION;
+
+/* Put each element of the composite type column in the SELECT list. */
+EXEC SQL DECLARE cur1 CURSOR FOR SELECT (compval).intval, (compval).textval FROM t4;
+EXEC SQL OPEN cur1;
+
+EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+while (1)
+{
+    /* Put all values in the SELECT list into one structure. */
+    EXEC SQL FETCH FROM cur1 INTO :compval;
+
+    printf("intval=%d, textval=%s\n", compval.intval, compval.textval.arr);
+}
+
+EXEC SQL CLOSE cur1;
+</programlisting>
+
+     Although a structure is used in the <command>FETCH</command>
+     command, the attribute names in the <command>SELECT</command>
+     clause are specified one by one.  This can be enhanced by using
+     a <literal>*</literal> to ask for all attributes of the composite
+     type value.
+<programlisting>
+...
+EXEC SQL DECLARE cur1 CURSOR FOR SELECT (compval).* FROM t4;
+EXEC SQL OPEN cur1;
+
+EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+while (1)
+{
+    /* Put all values in the SELECT list into one structure. */
+    EXEC SQL FETCH FROM cur1 INTO :compval;
+
+    printf("intval=%d, textval=%s\n", compval.intval, compval.textval.arr);
+}
+...
+</programlisting>
+     This way, composite types can be mapped into structures almost
+     seamlessly, even though ECPG does not understand the composite
+     type itself.
+    </para>
+
+    <para>
+     Finally, it is also possible to store composite type values in
+     their external string representation in host variables of
+     type <type>char[]</type> or <type>VARCHAR[]</type>.  But that
+     way, it is not easily possible to access the fields of the value
+     from the host program.
+    </para>
+   </sect3>
+
+   <sect3 id="ecpg-variables-nonprimitive-sql-user-defined-base-types">
+    <title>User-Defined Base Types</title>
+
+    <para>
+     New user-defined base types are not directly supported by ECPG.
+     You can use the external string representation and host variables
+     of type <type>char[]</type> or <type>VARCHAR[]</type>, and this
+     solution is indeed appropriate and sufficient for many types.
+    </para>
+
+    <para>
+     Here is an example using the data type <type>complex</type> from
+     the example in <xref linkend="xtypes"/>.  The external string
+     representation of that type is <literal>(%f,%f)</literal>,
+     which is defined in the
+     functions <function>complex_in()</function>
+     and <function>complex_out()</function> functions
+     in <xref linkend="xtypes"/>.  The following example inserts the
+     complex type values <literal>(1,1)</literal>
+     and <literal>(3,3)</literal> into the
+     columns <literal>a</literal> and <literal>b</literal>, and select
+     them from the table after that.
+
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+    varchar a[64];
+    varchar b[64];
+EXEC SQL END DECLARE SECTION;
+
+    EXEC SQL INSERT INTO test_complex VALUES ('(1,1)', '(3,3)');
+
+    EXEC SQL DECLARE cur1 CURSOR FOR SELECT a, b FROM test_complex;
+    EXEC SQL OPEN cur1;
+
+    EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+    while (1)
+    {
+        EXEC SQL FETCH FROM cur1 INTO :a, :b;
+        printf("a=%s, b=%s\n", a.arr, b.arr);
+    }
+
+    EXEC SQL CLOSE cur1;
+</programlisting>
+
+     This example shows following result:
+<screen>
+a=(1,1), b=(3,3)
+</screen>
+   </para>
+
+    <para>
+     Another workaround is avoiding the direct use of the user-defined
+     types in ECPG and instead create a function or cast that converts
+     between the user-defined type and a primitive type that ECPG can
+     handle.  Note, however, that type casts, especially implicit
+     ones, should be introduced into the type system very carefully.
+    </para>
+
+    <para>
+     For example,
+<programlisting>
+CREATE FUNCTION create_complex(r double, i double) RETURNS complex
+LANGUAGE SQL
+IMMUTABLE
+AS $$ SELECT $1 * complex '(1,0')' + $2 * complex '(0,1)' $$;
+</programlisting>
+    After this definition, the following
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+double a, b, c, d;
+EXEC SQL END DECLARE SECTION;
+
+a = 1;
+b = 2;
+c = 3;
+d = 4;
+
+EXEC SQL INSERT INTO test_complex VALUES (create_complex(:a, :b), create_complex(:c, :d));
+</programlisting>
+    has the same effect as
+<programlisting>
+EXEC SQL INSERT INTO test_complex VALUES ('(1,2)', '(3,4)');
+</programlisting>
+    </para>
+   </sect3>
+  </sect2>
+
+  <sect2 id="ecpg-indicators">
+   <title>Indicators</title>
+
+   <para>
+    The examples above do not handle null values.  In fact, the
+    retrieval examples will raise an error if they fetch a null value
+    from the database.  To be able to pass null values to the database
+    or retrieve null values from the database, you need to append a
+    second host variable specification to each host variable that
+    contains data.  This second host variable is called the
+    <firstterm>indicator</firstterm> and contains a flag that tells
+    whether the datum is null, in which case the value of the real
+    host variable is ignored.  Here is an example that handles the
+    retrieval of null values correctly:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+VARCHAR val;
+int val_ind;
+EXEC SQL END DECLARE SECTION:
+
+ ...
+
+EXEC SQL SELECT b INTO :val :val_ind FROM test1;
+</programlisting>
+    The indicator variable <varname>val_ind</varname> will be zero if
+    the value was not null, and it will be negative if the value was
+    null.  (See <xref linkend="ecpg-oracle-compat"/> to enable
+    Oracle-specific behavior.)
+   </para>
+
+   <para>
+    The indicator has another function: if the indicator value is
+    positive, it means that the value is not null, but it was
+    truncated when it was stored in the host variable.
+   </para>
+
+   <para>
+    If the argument <literal>-r no_indicator</literal> is passed to
+    the preprocessor <command>ecpg</command>, it works in
+    <quote>no-indicator</quote> mode. In no-indicator mode, if no
+    indicator variable is specified, null values are signaled (on
+    input and output) for character string types as empty string and
+    for integer types as the lowest possible value for type (for
+    example, <symbol>INT_MIN</symbol> for <type>int</type>).
+   </para>
+  </sect2>
+ </sect1>
+
+ <sect1 id="ecpg-dynamic">
+  <title>Dynamic SQL</title>
+
+  <para>
+   In many cases, the particular SQL statements that an application
+   has to execute are known at the time the application is written.
+   In some cases, however, the SQL statements are composed at run time
+   or provided by an external source.  In these cases you cannot embed
+   the SQL statements directly into the C source code, but there is a
+   facility that allows you to call arbitrary SQL statements that you
+   provide in a string variable.
+  </para>
+
+  <sect2 id="ecpg-dynamic-without-result">
+   <title>Executing Statements without a Result Set</title>
+
+   <para>
+    The simplest way to execute an arbitrary SQL statement is to use
+    the command <command>EXECUTE IMMEDIATE</command>.  For example:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+const char *stmt = "CREATE TABLE test1 (...);";
+EXEC SQL END DECLARE SECTION;
+
+EXEC SQL EXECUTE IMMEDIATE :stmt;
+</programlisting>
+    <command>EXECUTE IMMEDIATE</command> can be used for SQL
+    statements that do not return a result set (e.g.,
+    DDL, <command>INSERT</command>, <command>UPDATE</command>,
+    <command>DELETE</command>).  You cannot execute statements that
+    retrieve data (e.g., <command>SELECT</command>) this way.  The
+    next section describes how to do that.
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-dynamic-input">
+   <title>Executing a Statement with Input Parameters</title>
+
+   <para>
+    A more powerful way to execute arbitrary SQL statements is to
+    prepare them once and execute the prepared statement as often as
+    you like.  It is also possible to prepare a generalized version of
+    a statement and then execute specific versions of it by
+    substituting parameters.  When preparing the statement, write
+    question marks where you want to substitute parameters later.  For
+    example:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+const char *stmt = "INSERT INTO test1 VALUES(?, ?);";
+EXEC SQL END DECLARE SECTION;
+
+EXEC SQL PREPARE mystmt FROM :stmt;
+ ...
+EXEC SQL EXECUTE mystmt USING 42, 'foobar';
+</programlisting>
+   </para>
+
+   <para>
+    When you don't need the prepared statement anymore, you should
+    deallocate it:
+<programlisting>
+EXEC SQL DEALLOCATE PREPARE <replaceable>name</replaceable>;
+</programlisting>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-dynamic-with-result">
+   <title>Executing a Statement with a Result Set</title>
+
+   <para>
+    To execute an SQL statement with a single result row,
+    <command>EXECUTE</command> can be used.  To save the result, add
+    an <literal>INTO</literal> clause.
+<programlisting><![CDATA[
+EXEC SQL BEGIN DECLARE SECTION;
+const char *stmt = "SELECT a, b, c FROM test1 WHERE a > ?";
+int v1, v2;
+VARCHAR v3[50];
+EXEC SQL END DECLARE SECTION;
+
+EXEC SQL PREPARE mystmt FROM :stmt;
+ ...
+EXEC SQL EXECUTE mystmt INTO :v1, :v2, :v3 USING 37;
+]]>
+</programlisting>
+    An <command>EXECUTE</command> command can have an
+    <literal>INTO</literal> clause, a <literal>USING</literal> clause,
+    both, or neither.
+   </para>
+
+   <para>
+    If a query is expected to return more than one result row, a
+    cursor should be used, as in the following example.
+    (See <xref linkend="ecpg-cursors"/> for more details about the
+    cursor.)
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+char dbaname[128];
+char datname[128];
+char *stmt = "SELECT u.usename as dbaname, d.datname "
+             "  FROM pg_database d, pg_user u "
+             "  WHERE d.datdba = u.usesysid";
+EXEC SQL END DECLARE SECTION;
+
+EXEC SQL CONNECT TO testdb AS con1 USER testuser;
+EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+
+EXEC SQL PREPARE stmt1 FROM :stmt;
+
+EXEC SQL DECLARE cursor1 CURSOR FOR stmt1;
+EXEC SQL OPEN cursor1;
+
+EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+while (1)
+{
+    EXEC SQL FETCH cursor1 INTO :dbaname,:datname;
+    printf("dbaname=%s, datname=%s\n", dbaname, datname);
+}
+
+EXEC SQL CLOSE cursor1;
+
+EXEC SQL COMMIT;
+EXEC SQL DISCONNECT ALL;
+</programlisting>
+   </para>
+  </sect2>
+ </sect1>
+
+ <sect1 id="ecpg-pgtypes">
+  <title>pgtypes Library</title>
+
+  <para>
+   The pgtypes library maps <productname>PostgreSQL</productname> database
+   types to C equivalents that can be used in C programs. It also offers
+   functions to do basic calculations with those types within C, i.e., without
+   the help of the <productname>PostgreSQL</productname> server. See the
+   following example:
+<programlisting><![CDATA[
+EXEC SQL BEGIN DECLARE SECTION;
+   date date1;
+   timestamp ts1, tsout;
+   interval iv1;
+   char *out;
+EXEC SQL END DECLARE SECTION;
+
+PGTYPESdate_today(&date1);
+EXEC SQL SELECT started, duration INTO :ts1, :iv1 FROM datetbl WHERE d=:date1;
+PGTYPEStimestamp_add_interval(&ts1, &iv1, &tsout);
+out = PGTYPEStimestamp_to_asc(&tsout);
+printf("Started + duration: %s\n", out);
+PGTYPESchar_free(out);
+]]>
+</programlisting>
+  </para>
+
+  <sect2 id="ecpg-pgtypes-cstrings">
+   <title>Character Strings</title>
+   <para>
+   Some functions such as <function>PGTYPESnumeric_to_asc</function> return
+   a pointer to a freshly allocated character string. These results should be
+   freed with <function>PGTYPESchar_free</function> instead of
+   <function>free</function>. (This is important only on Windows, where
+   memory allocation and release sometimes need to be done by the same
+   library.)
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-pgtypes-numeric">
+   <title>The numeric Type</title>
+   <para>
+    The numeric type offers to do calculations with arbitrary precision. See
+    <xref linkend="datatype-numeric"/> for the equivalent type in the
+    <productname>PostgreSQL</productname> server. Because of the arbitrary precision this
+    variable needs to be able to expand and shrink dynamically. That's why you
+    can only create numeric variables on the heap, by means of the
+    <function>PGTYPESnumeric_new</function> and <function>PGTYPESnumeric_free</function>
+    functions. The decimal type, which is similar but limited in precision,
+    can be created on the stack as well as on the heap.
+   </para>
+   <para>
+   The following functions can be used to work with the numeric type:
+   <variablelist>
+    <varlistentry id="ecpg-pgtypes-numeric-new">
+     <term><function>PGTYPESnumeric_new</function></term>
+     <listitem>
+      <para>
+      Request a pointer to a newly allocated numeric variable.
+<synopsis>
+numeric *PGTYPESnumeric_new(void);
+</synopsis>
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-free">
+     <term><function>PGTYPESnumeric_free</function></term>
+     <listitem>
+      <para>
+      Free a numeric type, release all of its memory.
+<synopsis>
+void PGTYPESnumeric_free(numeric *var);
+</synopsis>
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-from-asc">
+     <term><function>PGTYPESnumeric_from_asc</function></term>
+     <listitem>
+      <para>
+       Parse a numeric type from its string notation.
+<synopsis>
+numeric *PGTYPESnumeric_from_asc(char *str, char **endptr);
+</synopsis>
+       Valid formats are for example:
+        <literal>-2</literal>,
+        <literal>.794</literal>,
+        <literal>+3.44</literal>,
+        <literal>592.49E07</literal> or
+        <literal>-32.84e-4</literal>.
+       If the value could be parsed successfully, a valid pointer is returned,
+       else the NULL pointer. At the moment ECPG always parses the complete
+       string and so it currently does not support to store the address of the
+       first invalid character in <literal>*endptr</literal>. You can safely
+       set <literal>endptr</literal> to NULL.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-to-asc">
+     <term><function>PGTYPESnumeric_to_asc</function></term>
+     <listitem>
+      <para>
+       Returns a pointer to a string allocated by <function>malloc</function> that contains the string
+       representation of the numeric type <literal>num</literal>.
+<synopsis>
+char *PGTYPESnumeric_to_asc(numeric *num, int dscale);
+</synopsis>
+       The numeric value will be printed with <literal>dscale</literal> decimal
+       digits, with rounding applied if necessary.
+       The result must be freed with <function>PGTYPESchar_free()</function>.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-add">
+     <term><function>PGTYPESnumeric_add</function></term>
+     <listitem>
+      <para>
+       Add two numeric variables into a third one.
+<synopsis>
+int PGTYPESnumeric_add(numeric *var1, numeric *var2, numeric *result);
+</synopsis>
+       The function adds the variables <literal>var1</literal> and
+       <literal>var2</literal> into the result variable
+       <literal>result</literal>.
+       The function returns 0 on success and -1 in case of error.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-sub">
+     <term><function>PGTYPESnumeric_sub</function></term>
+     <listitem>
+      <para>
+       Subtract two numeric variables and return the result in a third one.
+<synopsis>
+int PGTYPESnumeric_sub(numeric *var1, numeric *var2, numeric *result);
+</synopsis>
+       The function subtracts the variable <literal>var2</literal> from
+       the variable <literal>var1</literal>. The result of the operation is
+       stored in the variable <literal>result</literal>.
+       The function returns 0 on success and -1 in case of error.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-mul">
+     <term><function>PGTYPESnumeric_mul</function></term>
+     <listitem>
+      <para>
+       Multiply two numeric variables and return the result in a third one.
+<synopsis>
+int PGTYPESnumeric_mul(numeric *var1, numeric *var2, numeric *result);
+</synopsis>
+       The function multiplies the variables <literal>var1</literal> and
+       <literal>var2</literal>. The result of the operation is stored in the
+       variable <literal>result</literal>.
+       The function returns 0 on success and -1 in case of error.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-div">
+     <term><function>PGTYPESnumeric_div</function></term>
+     <listitem>
+      <para>
+       Divide two numeric variables and return the result in a third one.
+<synopsis>
+int PGTYPESnumeric_div(numeric *var1, numeric *var2, numeric *result);
+</synopsis>
+       The function divides the variables <literal>var1</literal> by
+       <literal>var2</literal>. The result of the operation is stored in the
+       variable <literal>result</literal>.
+       The function returns 0 on success and -1 in case of error.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-cmp">
+     <term><function>PGTYPESnumeric_cmp</function></term>
+     <listitem>
+      <para>
+       Compare two numeric variables.
+<synopsis>
+int PGTYPESnumeric_cmp(numeric *var1, numeric *var2)
+</synopsis>
+       This function compares two numeric variables. In case of error,
+       <literal>INT_MAX</literal> is returned. On success, the function
+       returns one of three possible results:
+       <itemizedlist>
+        <listitem>
+         <para>
+          1, if <literal>var1</literal> is bigger than <literal>var2</literal>
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          -1, if <literal>var1</literal> is smaller than <literal>var2</literal>
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          0, if <literal>var1</literal> and <literal>var2</literal> are equal
+         </para>
+        </listitem>
+       </itemizedlist>
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-from-int">
+     <term><function>PGTYPESnumeric_from_int</function></term>
+     <listitem>
+      <para>
+       Convert an int variable to a numeric variable.
+<synopsis>
+int PGTYPESnumeric_from_int(signed int int_val, numeric *var);
+</synopsis>
+       This function accepts a variable of type signed int and stores it
+       in the numeric variable <literal>var</literal>. Upon success, 0 is returned and
+       -1 in case of a failure.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-from-long">
+     <term><function>PGTYPESnumeric_from_long</function></term>
+     <listitem>
+      <para>
+       Convert a long int variable to a numeric variable.
+<synopsis>
+int PGTYPESnumeric_from_long(signed long int long_val, numeric *var);
+</synopsis>
+       This function accepts a variable of type signed long int and stores it
+       in the numeric variable <literal>var</literal>. Upon success, 0 is returned and
+       -1 in case of a failure.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-copy">
+     <term><function>PGTYPESnumeric_copy</function></term>
+     <listitem>
+      <para>
+       Copy over one numeric variable into another one.
+<synopsis>
+int PGTYPESnumeric_copy(numeric *src, numeric *dst);
+</synopsis>
+       This function copies over the value of the variable that
+       <literal>src</literal> points to into the variable that <literal>dst</literal>
+       points to. It returns 0 on success and -1 if an error occurs.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-from-double">
+     <term><function>PGTYPESnumeric_from_double</function></term>
+     <listitem>
+      <para>
+       Convert a variable of type double to a numeric.
+<synopsis>
+int  PGTYPESnumeric_from_double(double d, numeric *dst);
+</synopsis>
+       This function accepts a variable of type double and stores the result
+       in the variable that <literal>dst</literal> points to. It returns 0 on success
+       and -1 if an error occurs.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-to-double">
+     <term><function>PGTYPESnumeric_to_double</function></term>
+     <listitem>
+      <para>
+       Convert a variable of type numeric to double.
+<synopsis>
+int PGTYPESnumeric_to_double(numeric *nv, double *dp)
+</synopsis>
+       The function converts the numeric value from the variable that
+       <literal>nv</literal> points to into the double variable that <literal>dp</literal> points
+       to. It returns 0 on success and -1 if an error occurs, including
+       overflow. On overflow, the global variable <literal>errno</literal> will be set
+       to <literal>PGTYPES_NUM_OVERFLOW</literal> additionally.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-to-int">
+     <term><function>PGTYPESnumeric_to_int</function></term>
+     <listitem>
+      <para>
+       Convert a variable of type numeric to int.
+<synopsis>
+int PGTYPESnumeric_to_int(numeric *nv, int *ip);
+</synopsis>
+       The function converts the numeric value from the variable that
+       <literal>nv</literal> points to into the integer variable that <literal>ip</literal>
+       points to. It returns 0 on success and -1 if an error occurs, including
+       overflow. On overflow, the global variable <literal>errno</literal> will be set
+       to <literal>PGTYPES_NUM_OVERFLOW</literal> additionally.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-to-long">
+     <term><function>PGTYPESnumeric_to_long</function></term>
+     <listitem>
+      <para>
+       Convert a variable of type numeric to long.
+<synopsis>
+int PGTYPESnumeric_to_long(numeric *nv, long *lp);
+</synopsis>
+       The function converts the numeric value from the variable that
+       <literal>nv</literal> points to into the long integer variable that
+       <literal>lp</literal> points to. It returns 0 on success and -1 if an error
+       occurs, including overflow. On overflow, the global variable
+       <literal>errno</literal> will be set to <literal>PGTYPES_NUM_OVERFLOW</literal>
+       additionally.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-to-decimal">
+     <term><function>PGTYPESnumeric_to_decimal</function></term>
+     <listitem>
+      <para>
+       Convert a variable of type numeric to decimal.
+<synopsis>
+int PGTYPESnumeric_to_decimal(numeric *src, decimal *dst);
+</synopsis>
+       The function converts the numeric value from the variable that
+       <literal>src</literal> points to into the decimal variable that
+       <literal>dst</literal> points to. It returns 0 on success and -1 if an error
+       occurs, including overflow. On overflow, the global variable
+       <literal>errno</literal> will be set to <literal>PGTYPES_NUM_OVERFLOW</literal>
+       additionally.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-pgtypes-numeric-from-decimal">
+     <term><function>PGTYPESnumeric_from_decimal</function></term>
+     <listitem>
+      <para>
+       Convert a variable of type decimal to numeric.
+<synopsis>
+int PGTYPESnumeric_from_decimal(decimal *src, numeric *dst);
+</synopsis>
+       The function converts the decimal value from the variable that
+       <literal>src</literal> points to into the numeric variable that
+       <literal>dst</literal> points to. It returns 0 on success and -1 if an error
+       occurs. Since the decimal type is implemented as a limited version of
+       the numeric type, overflow cannot occur with this conversion.
+      </para>
+     </listitem>
+    </varlistentry>
+   </variablelist>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-pgtypes-date">
+   <title>The date Type</title>
+   <para>
+    The date type in C enables your programs to deal with data of the SQL type
+    date. See <xref linkend="datatype-datetime"/> for the equivalent type in the
+    <productname>PostgreSQL</productname> server.
+   </para>
+   <para>
+    The following functions can be used to work with the date type:
+    <variablelist>
+     <varlistentry id="pgtypesdatefromtimestamp">
+      <term><function>PGTYPESdate_from_timestamp</function></term>
+      <listitem>
+       <para>
+        Extract the date part from a timestamp.
+<synopsis>
+date PGTYPESdate_from_timestamp(timestamp dt);
+</synopsis>
+        The function receives a timestamp as its only argument and returns the
+        extracted date part from this timestamp.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesdatefromasc">
+      <term><function>PGTYPESdate_from_asc</function></term>
+      <listitem>
+       <para>
+       Parse a date from its textual representation.
+<synopsis>
+date PGTYPESdate_from_asc(char *str, char **endptr);
+</synopsis>
+        The function receives a C char* string <literal>str</literal> and a pointer to
+        a C char* string <literal>endptr</literal>. At the moment ECPG always parses
+        the complete string and so it currently does not support to store the
+        address of the first invalid character in <literal>*endptr</literal>.
+        You can safely set <literal>endptr</literal> to NULL.
+       </para>
+       <para>
+        Note that the function always assumes MDY-formatted dates and there is
+        currently no variable to change that within ECPG.
+       </para>
+       <para>
+        <xref linkend="ecpg-pgtypesdate-from-asc-table"/> shows the allowed input formats.
+       </para>
+        <table id="ecpg-pgtypesdate-from-asc-table">
+         <title>Valid Input Formats for <function>PGTYPESdate_from_asc</function></title>
+         <tgroup cols="2">
+          <thead>
+           <row>
+            <entry>Input</entry>
+            <entry>Result</entry>
+           </row>
+          </thead>
+          <tbody>
+           <row>
+            <entry><literal>January 8, 1999</literal></entry>
+            <entry><literal>January 8, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>1999-01-08</literal></entry>
+            <entry><literal>January 8, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>1/8/1999</literal></entry>
+            <entry><literal>January 8, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>1/18/1999</literal></entry>
+            <entry><literal>January 18, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>01/02/03</literal></entry>
+            <entry><literal>February 1, 2003</literal></entry>
+           </row>
+           <row>
+            <entry><literal>1999-Jan-08</literal></entry>
+            <entry><literal>January 8, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>Jan-08-1999</literal></entry>
+            <entry><literal>January 8, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>08-Jan-1999</literal></entry>
+            <entry><literal>January 8, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>99-Jan-08</literal></entry>
+            <entry><literal>January 8, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>08-Jan-99</literal></entry>
+            <entry><literal>January 8, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>08-Jan-06</literal></entry>
+            <entry><literal>January 8, 2006</literal></entry>
+           </row>
+           <row>
+            <entry><literal>Jan-08-99</literal></entry>
+            <entry><literal>January 8, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>19990108</literal></entry>
+            <entry><literal>ISO 8601; January 8, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>990108</literal></entry>
+            <entry><literal>ISO 8601; January 8, 1999</literal></entry>
+           </row>
+           <row>
+            <entry><literal>1999.008</literal></entry>
+            <entry><literal>year and day of year</literal></entry>
+           </row>
+           <row>
+            <entry><literal>J2451187</literal></entry>
+            <entry><literal>Julian day</literal></entry>
+           </row>
+           <row>
+            <entry><literal>January 8, 99 BC</literal></entry>
+            <entry><literal>year 99 before the Common Era</literal></entry>
+           </row>
+          </tbody>
+         </tgroup>
+        </table>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesdatetoasc">
+      <term><function>PGTYPESdate_to_asc</function></term>
+      <listitem>
+       <para>
+        Return the textual representation of a date variable.
+<synopsis>
+char *PGTYPESdate_to_asc(date dDate);
+</synopsis>
+        The function receives the date <literal>dDate</literal> as its only parameter.
+        It will output the date in the form <literal>1999-01-18</literal>, i.e., in the
+        <literal>YYYY-MM-DD</literal> format.
+        The result must be freed with <function>PGTYPESchar_free()</function>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesdatejulmdy">
+      <term><function>PGTYPESdate_julmdy</function></term>
+      <listitem>
+       <para>
+        Extract the values for the day, the month and the year from a variable
+        of type date.
+<synopsis>
+void PGTYPESdate_julmdy(date d, int *mdy);
+</synopsis>
+       <!-- almost same description as for rjulmdy() -->
+        The function receives the date <literal>d</literal> and a pointer to an array
+        of 3 integer values <literal>mdy</literal>. The variable name indicates
+        the sequential order: <literal>mdy[0]</literal> will be set to contain the
+        number of the month, <literal>mdy[1]</literal> will be set to the value of the
+        day and <literal>mdy[2]</literal> will contain the year.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesdatemdyjul">
+      <term><function>PGTYPESdate_mdyjul</function></term>
+      <listitem>
+       <para>
+        Create a date value from an array of 3 integers that specify the
+        day, the month and the year of the date.
+<synopsis>
+void PGTYPESdate_mdyjul(int *mdy, date *jdate);
+</synopsis>
+        The function receives the array of the 3 integers (<literal>mdy</literal>) as
+        its first argument and as its second argument a pointer to a variable
+        of type date that should hold the result of the operation.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesdatedayofweek">
+      <term><function>PGTYPESdate_dayofweek</function></term>
+      <listitem>
+       <para>
+        Return a number representing the day of the week for a date value.
+<synopsis>
+int PGTYPESdate_dayofweek(date d);
+</synopsis>
+        The function receives the date variable <literal>d</literal> as its only
+        argument and returns an integer that indicates the day of the week for
+        this date.
+        <itemizedlist>
+         <listitem>
+          <para>
+           0 - Sunday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           1 - Monday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           2 - Tuesday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           3 - Wednesday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           4 - Thursday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           5 - Friday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           6 - Saturday
+          </para>
+         </listitem>
+        </itemizedlist>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesdatetoday">
+      <term><function>PGTYPESdate_today</function></term>
+      <listitem>
+       <para>
+        Get the current date.
+<synopsis>
+void PGTYPESdate_today(date *d);
+</synopsis>
+        The function receives a pointer to a date variable (<literal>d</literal>)
+        that it sets to the current date.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesdatefmtasc">
+      <term><function>PGTYPESdate_fmt_asc</function></term>
+      <listitem>
+       <para>
+        Convert a variable of type date to its textual representation using a
+        format mask.
+<synopsis>
+int PGTYPESdate_fmt_asc(date dDate, char *fmtstring, char *outbuf);
+</synopsis>
+        The function receives the date to convert (<literal>dDate</literal>), the
+        format mask (<literal>fmtstring</literal>) and the string that will hold the
+        textual representation of the date (<literal>outbuf</literal>).
+       </para>
+       <para>
+        On success, 0 is returned and a negative value if an error occurred.
+       </para>
+       <para>
+        The following literals are the field specifiers you can use:
+        <itemizedlist>
+         <listitem>
+          <para>
+           <literal>dd</literal> - The number of the day of the month.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>mm</literal> - The number of the month of the year.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>yy</literal> - The number of the year as a two digit number.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>yyyy</literal> - The number of the year as a four digit number.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>ddd</literal> - The name of the day (abbreviated).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>mmm</literal> - The name of the month (abbreviated).
+          </para>
+         </listitem>
+        </itemizedlist>
+        All other characters are copied 1:1 to the output string.
+       </para>
+       <para>
+        <xref linkend="ecpg-pgtypesdate-fmt-asc-example-table"/> indicates a few possible formats. This will give
+        you an idea of how to use this function. All output lines are based on
+        the same date: November 23, 1959.
+       </para>
+        <table id="ecpg-pgtypesdate-fmt-asc-example-table">
+         <title>Valid Input Formats for <function>PGTYPESdate_fmt_asc</function></title>
+         <tgroup cols="2">
+          <thead>
+           <row>
+            <entry>Format</entry>
+            <entry>Result</entry>
+           </row>
+          </thead>
+          <tbody>
+           <row>
+            <entry><literal>mmddyy</literal></entry>
+            <entry><literal>112359</literal></entry>
+           </row>
+           <row>
+            <entry><literal>ddmmyy</literal></entry>
+            <entry><literal>231159</literal></entry>
+           </row>
+           <row>
+            <entry><literal>yymmdd</literal></entry>
+            <entry><literal>591123</literal></entry>
+           </row>
+           <row>
+            <entry><literal>yy/mm/dd</literal></entry>
+            <entry><literal>59/11/23</literal></entry>
+           </row>
+           <row>
+            <entry><literal>yy mm dd</literal></entry>
+            <entry><literal>59 11 23</literal></entry>
+           </row>
+           <row>
+            <entry><literal>yy.mm.dd</literal></entry>
+            <entry><literal>59.11.23</literal></entry>
+           </row>
+           <row>
+            <entry><literal>.mm.yyyy.dd.</literal></entry>
+            <entry><literal>.11.1959.23.</literal></entry>
+           </row>
+           <row>
+            <entry><literal>mmm. dd, yyyy</literal></entry>
+            <entry><literal>Nov. 23, 1959</literal></entry>
+           </row>
+           <row>
+            <entry><literal>mmm dd yyyy</literal></entry>
+            <entry><literal>Nov 23 1959</literal></entry>
+           </row>
+           <row>
+            <entry><literal>yyyy dd mm</literal></entry>
+            <entry><literal>1959 23 11</literal></entry>
+           </row>
+           <row>
+            <entry><literal>ddd, mmm. dd, yyyy</literal></entry>
+            <entry><literal>Mon, Nov. 23, 1959</literal></entry>
+           </row>
+           <row>
+            <entry><literal>(ddd) mmm. dd, yyyy</literal></entry>
+            <entry><literal>(Mon) Nov. 23, 1959</literal></entry>
+           </row>
+          </tbody>
+         </tgroup>
+        </table>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesdatedefmtasc">
+      <term><function>PGTYPESdate_defmt_asc</function></term>
+      <listitem>
+       <para>
+        Use a format mask to convert a C <type>char*</type> string to a value of type
+        date.
+<synopsis>
+int PGTYPESdate_defmt_asc(date *d, char *fmt, char *str);
+</synopsis>
+        <!-- same description as rdefmtdate -->
+        The function receives a pointer to the date value that should hold the
+        result of the operation (<literal>d</literal>), the format mask to use for
+        parsing the date (<literal>fmt</literal>) and the C char* string containing
+        the textual representation of the date (<literal>str</literal>). The textual
+        representation is expected to match the format mask. However you do not
+        need to have a 1:1 mapping of the string to the format mask. The
+        function only analyzes the sequential order and looks for the literals
+        <literal>yy</literal> or <literal>yyyy</literal> that indicate the
+        position of the year, <literal>mm</literal> to indicate the position of
+        the month and <literal>dd</literal> to indicate the position of the
+        day.
+       </para>
+       <para>
+        <xref linkend="ecpg-rdefmtdate-example-table"/> indicates a few possible formats. This will give
+        you an idea of how to use this function.
+       </para>
+        <table id="ecpg-rdefmtdate-example-table">
+         <title>Valid Input Formats for <function>rdefmtdate</function></title>
+         <tgroup cols="3">
+          <thead>
+           <row>
+            <entry>Format</entry>
+            <entry>String</entry>
+            <entry>Result</entry>
+           </row>
+          </thead>
+          <tbody>
+           <row>
+            <entry><literal>ddmmyy</literal></entry>
+            <entry><literal>21-2-54</literal></entry>
+            <entry><literal>1954-02-21</literal></entry>
+           </row>
+           <row>
+            <entry><literal>ddmmyy</literal></entry>
+            <entry><literal>2-12-54</literal></entry>
+            <entry><literal>1954-12-02</literal></entry>
+           </row>
+           <row>
+            <entry><literal>ddmmyy</literal></entry>
+            <entry><literal>20111954</literal></entry>
+            <entry><literal>1954-11-20</literal></entry>
+           </row>
+           <row>
+            <entry><literal>ddmmyy</literal></entry>
+            <entry><literal>130464</literal></entry>
+            <entry><literal>1964-04-13</literal></entry>
+           </row>
+           <row>
+            <entry><literal>mmm.dd.yyyy</literal></entry>
+            <entry><literal>MAR-12-1967</literal></entry>
+            <entry><literal>1967-03-12</literal></entry>
+           </row>
+           <row>
+            <entry><literal>yy/mm/dd</literal></entry>
+            <entry><literal>1954, February 3rd</literal></entry>
+            <entry><literal>1954-02-03</literal></entry>
+           </row>
+           <row>
+            <entry><literal>mmm.dd.yyyy</literal></entry>
+            <entry><literal>041269</literal></entry>
+            <entry><literal>1969-04-12</literal></entry>
+           </row>
+           <row>
+            <entry><literal>yy/mm/dd</literal></entry>
+            <entry><literal>In the year 2525, in the month of July, mankind will be alive on the 28th day</literal></entry>
+            <entry><literal>2525-07-28</literal></entry>
+           </row>
+           <row>
+            <entry><literal>dd-mm-yy</literal></entry>
+            <entry><literal>I said on the 28th of July in the year 2525</literal></entry>
+            <entry><literal>2525-07-28</literal></entry>
+           </row>
+           <row>
+            <entry><literal>mmm.dd.yyyy</literal></entry>
+            <entry><literal>9/14/58</literal></entry>
+            <entry><literal>1958-09-14</literal></entry>
+           </row>
+           <row>
+            <entry><literal>yy/mm/dd</literal></entry>
+            <entry><literal>47/03/29</literal></entry>
+            <entry><literal>1947-03-29</literal></entry>
+           </row>
+           <row>
+            <entry><literal>mmm.dd.yyyy</literal></entry>
+            <entry><literal>oct 28 1975</literal></entry>
+            <entry><literal>1975-10-28</literal></entry>
+           </row>
+           <row>
+            <entry><literal>mmddyy</literal></entry>
+            <entry><literal>Nov 14th, 1985</literal></entry>
+            <entry><literal>1985-11-14</literal></entry>
+           </row>
+          </tbody>
+         </tgroup>
+        </table>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-pgtypes-timestamp">
+   <title>The timestamp Type</title>
+   <para>
+    The timestamp type in C enables your programs to deal with data of the SQL
+    type timestamp. See <xref linkend="datatype-datetime"/> for the equivalent
+    type in the <productname>PostgreSQL</productname> server.
+   </para>
+   <para>
+    The following functions can be used to work with the timestamp type:
+    <variablelist>
+     <varlistentry id="pgtypestimestampfromasc">
+      <term><function>PGTYPEStimestamp_from_asc</function></term>
+      <listitem>
+       <para>
+        Parse a timestamp from its textual representation into a timestamp
+        variable.
+<synopsis>
+timestamp PGTYPEStimestamp_from_asc(char *str, char **endptr);
+</synopsis>
+        The function receives the string to parse (<literal>str</literal>) and a
+        pointer to a C char* (<literal>endptr</literal>).
+        At the moment ECPG always parses
+        the complete string and so it currently does not support to store the
+        address of the first invalid character in <literal>*endptr</literal>.
+        You can safely set <literal>endptr</literal> to NULL.
+       </para>
+       <para>
+        The function returns the parsed timestamp on success. On error,
+        <literal>PGTYPESInvalidTimestamp</literal> is returned and <varname>errno</varname> is
+        set to <literal>PGTYPES_TS_BAD_TIMESTAMP</literal>. See <xref linkend="pgtypesinvalidtimestamp"/> for important notes on this value.
+       </para>
+       <para>
+        In general, the input string can contain any combination of an allowed
+        date specification, a whitespace character and an allowed time
+        specification. Note that time zones are not supported by ECPG. It can
+        parse them but does not apply any calculation as the
+        <productname>PostgreSQL</productname> server does for example. Timezone
+        specifiers are silently discarded.
+       </para>
+       <para>
+        <xref linkend="ecpg-pgtypestimestamp-from-asc-example-table"/> contains a few examples for input strings.
+       </para>
+        <table id="ecpg-pgtypestimestamp-from-asc-example-table">
+         <title>Valid Input Formats for <function>PGTYPEStimestamp_from_asc</function></title>
+         <tgroup cols="2">
+          <thead>
+           <row>
+            <entry>Input</entry>
+            <entry>Result</entry>
+           </row>
+          </thead>
+          <tbody>
+           <row>
+            <entry><literal>1999-01-08 04:05:06</literal></entry>
+            <entry><literal>1999-01-08 04:05:06</literal></entry>
+           </row>
+           <row>
+            <entry><literal>January 8 04:05:06 1999 PST</literal></entry>
+            <entry><literal>1999-01-08 04:05:06</literal></entry>
+           </row>
+           <row>
+            <entry><literal>1999-Jan-08 04:05:06.789-8</literal></entry>
+            <entry><literal>1999-01-08 04:05:06.789 (time zone specifier ignored)</literal></entry>
+           </row>
+           <row>
+            <entry><literal>J2451187 04:05-08:00</literal></entry>
+            <entry><literal>1999-01-08 04:05:00 (time zone specifier ignored)</literal></entry>
+           </row>
+          </tbody>
+         </tgroup>
+        </table>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypestimestamptoasc">
+      <term><function>PGTYPEStimestamp_to_asc</function></term>
+      <listitem>
+       <para>
+        Converts a date to a C char* string.
+<synopsis>
+char *PGTYPEStimestamp_to_asc(timestamp tstamp);
+</synopsis>
+        The function receives the timestamp <literal>tstamp</literal> as
+        its only argument and returns an allocated string that contains the
+        textual representation of the timestamp.
+        The result must be freed with <function>PGTYPESchar_free()</function>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypestimestampcurrent">
+      <term><function>PGTYPEStimestamp_current</function></term>
+      <listitem>
+       <para>
+        Retrieve the current timestamp.
+<synopsis>
+void PGTYPEStimestamp_current(timestamp *ts);
+</synopsis>
+        The function retrieves the current timestamp and saves it into the
+        timestamp variable that <literal>ts</literal> points to.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypestimestampfmtasc">
+      <term><function>PGTYPEStimestamp_fmt_asc</function></term>
+      <listitem>
+       <para>
+        Convert a timestamp variable to a C char* using a format mask.
+<synopsis>
+int PGTYPEStimestamp_fmt_asc(timestamp *ts, char *output, int str_len, char *fmtstr);
+</synopsis>
+        The function receives a pointer to the timestamp to convert as its
+        first argument (<literal>ts</literal>), a pointer to the output buffer
+        (<literal>output</literal>), the maximal length that has been allocated for
+        the output buffer (<literal>str_len</literal>) and the format mask to
+        use for the conversion (<literal>fmtstr</literal>).
+       </para>
+       <para>
+        Upon success, the function returns 0 and a negative value if an
+        error occurred.
+       </para>
+       <para>
+        You can use the following format specifiers for the format mask. The
+        format specifiers are the same ones that are used in the
+        <function>strftime</function> function in <productname>libc</productname>. Any
+        non-format specifier will be copied into the output buffer.
+        <!-- This is from the FreeBSD man page:
+             http://www.freebsd.org/cgi/man.cgi?query=strftime&apropos=0&sektion=3&manpath=FreeBSD+7.0-current&format=html
+        -->
+        <itemizedlist>
+         <listitem>
+          <para>
+           <literal>%A</literal> - is replaced by national representation of
+           the full weekday name.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%a</literal> - is replaced by national representation of
+           the abbreviated weekday name.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%B</literal> - is replaced by national representation of
+           the full month name.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%b</literal> - is replaced by national representation of
+           the abbreviated month name.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%C</literal> - is replaced by (year / 100) as decimal
+           number; single digits are preceded by a zero.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%c</literal> - is replaced by national representation of
+           time and date.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%D</literal> - is equivalent to
+           <literal>%m/%d/%y</literal>.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%d</literal> - is replaced by the day of the month as a
+           decimal number (01&ndash;31).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%E*</literal> <literal>%O*</literal> -  POSIX locale
+           extensions. The sequences
+           <literal>%Ec</literal>
+           <literal>%EC</literal>
+           <literal>%Ex</literal>
+           <literal>%EX</literal>
+           <literal>%Ey</literal>
+           <literal>%EY</literal>
+           <literal>%Od</literal>
+           <literal>%Oe</literal>
+           <literal>%OH</literal>
+           <literal>%OI</literal>
+           <literal>%Om</literal>
+           <literal>%OM</literal>
+           <literal>%OS</literal>
+           <literal>%Ou</literal>
+           <literal>%OU</literal>
+           <literal>%OV</literal>
+           <literal>%Ow</literal>
+           <literal>%OW</literal>
+           <literal>%Oy</literal>
+           are supposed to provide alternative representations.
+          </para>
+          <para>
+           Additionally <literal>%OB</literal> implemented to represent
+           alternative months names (used standalone, without day mentioned).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%e</literal> - is replaced by the day of month as a decimal
+           number (1&ndash;31); single digits are preceded by a blank.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%F</literal> - is equivalent to <literal>%Y-%m-%d</literal>.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%G</literal> - is replaced by a year as a decimal number
+           with century. This year is the one that contains the greater part of
+           the week (Monday as the first day of the week).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%g</literal> - is replaced by the same year as in
+           <literal>%G</literal>, but as a decimal number without century
+           (00&ndash;99).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%H</literal> - is replaced by the hour (24-hour clock) as a
+           decimal number (00&ndash;23).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%h</literal> - the same as <literal>%b</literal>.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%I</literal> - is replaced by the hour (12-hour clock) as a
+           decimal number (01&ndash;12).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%j</literal> - is replaced by the day of the year as a
+           decimal number (001&ndash;366).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%k</literal> - is replaced by the hour (24-hour clock) as a
+           decimal number (0&ndash;23); single digits are preceded by a blank.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%l</literal> - is replaced by the hour (12-hour clock) as a
+           decimal number (1&ndash;12); single digits are preceded by a blank.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%M</literal> - is replaced by the minute as a decimal
+           number (00&ndash;59).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%m</literal> - is replaced by the month as a decimal number
+           (01&ndash;12).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+          <literal>%n</literal> - is replaced by a newline.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%O*</literal> - the same as <literal>%E*</literal>.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%p</literal> - is replaced by national representation of
+           either <quote>ante meridiem</quote> or <quote>post meridiem</quote> as appropriate.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%R</literal> - is equivalent to <literal>%H:%M</literal>.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%r</literal> - is equivalent to <literal>%I:%M:%S
+           %p</literal>.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%S</literal> - is replaced by the second as a decimal
+           number (00&ndash;60).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%s</literal> - is replaced by the number of seconds since
+           the Epoch, UTC.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%T</literal> - is equivalent to <literal>%H:%M:%S</literal>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%t</literal> - is replaced by a tab.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%U</literal> - is replaced by the week number of the year
+           (Sunday as the first day of the week) as a decimal number (00&ndash;53).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%u</literal> - is replaced by the weekday (Monday as the
+           first day of the week) as a decimal number (1&ndash;7).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%V</literal> - is replaced by the week number of the year
+           (Monday as the first day of the week) as a decimal number (01&ndash;53).
+           If the week containing January 1 has four or more days in the new
+           year, then it is week 1; otherwise it is the last week of the
+           previous year, and the next week is week 1.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%v</literal> - is equivalent to
+           <literal>%e-%b-%Y</literal>.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%W</literal> - is replaced by the week number of the year
+           (Monday as the first day of the week) as a decimal number (00&ndash;53).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%w</literal> - is replaced by the weekday (Sunday as the
+           first day of the week) as a decimal number (0&ndash;6).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%X</literal> - is replaced by national representation of
+           the time.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%x</literal> - is replaced by national representation of
+           the date.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%Y</literal> - is replaced by the year with century as a
+           decimal number.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%y</literal> - is replaced by the year without century as a
+           decimal number (00&ndash;99).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%Z</literal> - is replaced by the time zone name.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%z</literal> - is replaced by the time zone offset from
+           UTC; a leading plus sign stands for east of UTC, a minus sign for
+           west of UTC, hours and minutes follow with two digits each and no
+           delimiter between them (common form for <ulink url="https://tools.ietf.org/html/rfc822">RFC 822</ulink> date headers).
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%+</literal> - is replaced by national representation of
+           the date and time.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%-*</literal> - GNU libc extension. Do not do any padding
+           when performing numerical outputs.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           $_* - GNU libc extension.    Explicitly specify space for padding.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%0*</literal> - GNU libc extension. Explicitly specify zero
+           for padding.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>%%</literal> - is replaced by <literal>%</literal>.
+          </para>
+         </listitem>
+        </itemizedlist>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypestimestampsub">
+      <term><function>PGTYPEStimestamp_sub</function></term>
+      <listitem>
+       <para>
+        Subtract one timestamp from another one and save the result in a
+        variable of type interval.
+<synopsis>
+int PGTYPEStimestamp_sub(timestamp *ts1, timestamp *ts2, interval *iv);
+</synopsis>
+        The function will subtract the timestamp variable that <literal>ts2</literal>
+        points to from the timestamp variable that <literal>ts1</literal> points to
+        and will store the result in the interval variable that <literal>iv</literal>
+        points to.
+       </para>
+       <para>
+        Upon success, the function returns 0 and a negative value if an
+        error occurred.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypestimestampdefmtasc">
+      <term><function>PGTYPEStimestamp_defmt_asc</function></term>
+      <listitem>
+       <para>
+        Parse a timestamp value from its textual representation using a
+        formatting mask.
+<synopsis>
+int PGTYPEStimestamp_defmt_asc(char *str, char *fmt, timestamp *d);
+</synopsis>
+        The function receives the textual representation of a timestamp in the
+        variable <literal>str</literal> as well as the formatting mask to use in the
+        variable <literal>fmt</literal>. The result will be stored in the variable
+        that <literal>d</literal> points to.
+       </para>
+       <para>
+        If the formatting mask <literal>fmt</literal> is NULL, the function will fall
+        back to the default formatting mask which is <literal>%Y-%m-%d
+        %H:%M:%S</literal>.
+       </para>
+       <para>
+        This is the reverse function to <xref
+        linkend="pgtypestimestampfmtasc"/>.  See the documentation there in
+        order to find out about the possible formatting mask entries.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypestimestampaddinterval">
+      <term><function>PGTYPEStimestamp_add_interval</function></term>
+      <listitem>
+       <para>
+        Add an interval variable to a timestamp variable.
+<synopsis>
+int PGTYPEStimestamp_add_interval(timestamp *tin, interval *span, timestamp *tout);
+</synopsis>
+        The function receives a pointer to a timestamp variable <literal>tin</literal>
+        and a pointer to an interval variable <literal>span</literal>. It adds the
+        interval to the timestamp and saves the resulting timestamp in the
+        variable that <literal>tout</literal> points to.
+       </para>
+       <para>
+        Upon success, the function returns 0 and a negative value if an
+        error occurred.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypestimestampsubinterval">
+      <term><function>PGTYPEStimestamp_sub_interval</function></term>
+      <listitem>
+       <para>
+        Subtract an interval variable from a timestamp variable.
+<synopsis>
+int PGTYPEStimestamp_sub_interval(timestamp *tin, interval *span, timestamp *tout);
+</synopsis>
+        The function subtracts the interval variable that <literal>span</literal>
+        points to from the timestamp variable that <literal>tin</literal> points to
+        and saves the result into the variable that <literal>tout</literal> points
+        to.
+       </para>
+       <para>
+        Upon success, the function returns 0 and a negative value if an
+        error occurred.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-pgtypes-interval">
+   <title>The interval Type</title>
+   <para>
+    The interval type in C enables your programs to deal with data of the SQL
+    type interval. See <xref linkend="datatype-datetime"/> for the equivalent
+    type in the <productname>PostgreSQL</productname> server.
+   </para>
+   <para>
+    The following functions can be used to work with the interval type:
+    <variablelist>
+
+     <varlistentry id="pgtypesintervalnew">
+      <term><function>PGTYPESinterval_new</function></term>
+      <listitem>
+       <para>
+        Return a pointer to a newly allocated interval variable.
+<synopsis>
+interval *PGTYPESinterval_new(void);
+</synopsis>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesintervalfree">
+      <term><function>PGTYPESinterval_free</function></term>
+      <listitem>
+       <para>
+        Release the memory of a previously allocated interval variable.
+<synopsis>
+void PGTYPESinterval_free(interval *intvl);
+</synopsis>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesintervalfromasc">
+      <term><function>PGTYPESinterval_from_asc</function></term>
+      <listitem>
+       <para>
+        Parse an interval from its textual representation.
+<synopsis>
+interval *PGTYPESinterval_from_asc(char *str, char **endptr);
+</synopsis>
+        The function parses the input string <literal>str</literal> and returns a
+        pointer to an allocated interval variable.
+        At the moment ECPG always parses
+        the complete string and so it currently does not support to store the
+        address of the first invalid character in <literal>*endptr</literal>.
+        You can safely set <literal>endptr</literal> to NULL.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesintervaltoasc">
+      <term><function>PGTYPESinterval_to_asc</function></term>
+      <listitem>
+       <para>
+        Convert a variable of type interval to its textual representation.
+<synopsis>
+char *PGTYPESinterval_to_asc(interval *span);
+</synopsis>
+        The function converts the interval variable that <literal>span</literal>
+        points to into a C char*. The output looks like this example:
+        <literal>@ 1 day 12 hours 59 mins 10 secs</literal>.
+        The result must be freed with <function>PGTYPESchar_free()</function>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="pgtypesintervalcopy">
+      <term><function>PGTYPESinterval_copy</function></term>
+      <listitem>
+       <para>
+        Copy a variable of type interval.
+<synopsis>
+int PGTYPESinterval_copy(interval *intvlsrc, interval *intvldest);
+</synopsis>
+        The function copies the interval variable that <literal>intvlsrc</literal>
+        points to into the variable that <literal>intvldest</literal> points to. Note
+        that you need to allocate the memory for the destination variable
+        before.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-pgtypes-decimal">
+   <title>The decimal Type</title>
+   <para>
+     The decimal type is similar to the numeric type. However it is limited to
+     a maximum precision of 30 significant digits. In contrast to the numeric
+     type which can be created on the heap only, the decimal type can be
+     created either on the stack or on the heap (by means of the functions
+     <function>PGTYPESdecimal_new</function> and
+     <function>PGTYPESdecimal_free</function>).
+     There are a lot of other functions that deal with the decimal type in the
+     <productname>Informix</productname> compatibility mode described in <xref
+     linkend="ecpg-informix-compat"/>.
+   </para>
+   <para>
+    The following functions can be used to work with the decimal type and are
+    not only contained in the <literal>libcompat</literal> library.
+    <variablelist>
+     <varlistentry id="ecpg-pgtypes-decimal-new">
+      <term><function>PGTYPESdecimal_new</function></term>
+      <listitem>
+       <para>
+       Request a pointer to a newly allocated decimal variable.
+<synopsis>
+decimal *PGTYPESdecimal_new(void);
+</synopsis>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-decimal-free">
+      <term><function>PGTYPESdecimal_free</function></term>
+      <listitem>
+       <para>
+       Free a decimal type, release all of its memory.
+<synopsis>
+void PGTYPESdecimal_free(decimal *var);
+</synopsis>
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+  </sect2>
+
+   <sect2 id="ecpg-pgtypes-errno">
+    <title>errno Values of pgtypeslib</title>
+   <para>
+    <variablelist>
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-num-bad-numeric">
+      <term><literal>PGTYPES_NUM_BAD_NUMERIC</literal></term>
+      <listitem>
+       <para>
+        An argument should contain a numeric variable (or point to a numeric
+        variable) but in fact its in-memory representation was invalid.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-num-overflow">
+      <term><literal>PGTYPES_NUM_OVERFLOW</literal></term>
+      <listitem>
+       <para>
+        An overflow occurred. Since the numeric type can deal with almost
+        arbitrary precision, converting a numeric variable into other types
+        might cause overflow.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-num-underflow">
+      <term><literal>PGTYPES_NUM_UNDERFLOW</literal></term>
+      <listitem>
+       <para>
+        An underflow occurred. Since the numeric type can deal with almost
+        arbitrary precision, converting a numeric variable into other types
+        might cause underflow.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-num-divide-zero">
+      <term><literal>PGTYPES_NUM_DIVIDE_ZERO</literal></term>
+      <listitem>
+       <para>
+        A division by zero has been attempted.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-date-bad-date">
+      <term><literal>PGTYPES_DATE_BAD_DATE</literal></term>
+      <listitem>
+       <para>
+        An invalid date string was passed to
+        the <function>PGTYPESdate_from_asc</function> function.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-date-err-eargs">
+      <term><literal>PGTYPES_DATE_ERR_EARGS</literal></term>
+      <listitem>
+       <para>
+        Invalid arguments were passed to the
+        <function>PGTYPESdate_defmt_asc</function> function.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-date-err-enoshortdate">
+      <term><literal>PGTYPES_DATE_ERR_ENOSHORTDATE</literal></term>
+      <listitem>
+       <para>
+        An invalid token in the input string was found by the
+        <function>PGTYPESdate_defmt_asc</function> function.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-intvl-bad-interval">
+      <term><literal>PGTYPES_INTVL_BAD_INTERVAL</literal></term>
+      <listitem>
+       <para>
+        An invalid interval string was passed to the
+        <function>PGTYPESinterval_from_asc</function> function, or an
+        invalid interval value was passed to the
+        <function>PGTYPESinterval_to_asc</function> function.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-date-err-enotdmy">
+      <term><literal>PGTYPES_DATE_ERR_ENOTDMY</literal></term>
+      <listitem>
+       <para>
+        There was a mismatch in the day/month/year assignment in the
+        <function>PGTYPESdate_defmt_asc</function> function.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-date-bad-day">
+      <term><literal>PGTYPES_DATE_BAD_DAY</literal></term>
+      <listitem>
+       <para>
+        An invalid day of the month value was found by
+        the <function>PGTYPESdate_defmt_asc</function> function.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-date-bad-month">
+      <term><literal>PGTYPES_DATE_BAD_MONTH</literal></term>
+      <listitem>
+       <para>
+        An invalid month value was found by
+        the <function>PGTYPESdate_defmt_asc</function> function.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-ts-bad-timestamp">
+      <term><literal>PGTYPES_TS_BAD_TIMESTAMP</literal></term>
+      <listitem>
+       <para>
+        An invalid timestamp string pass passed to
+        the <function>PGTYPEStimestamp_from_asc</function> function,
+        or an invalid timestamp value was passed to
+        the <function>PGTYPEStimestamp_to_asc</function> function.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-pgtypes-errno-pgtypes-ts-err-einftime">
+      <term><literal>PGTYPES_TS_ERR_EINFTIME</literal></term>
+      <listitem>
+       <para>
+        An infinite timestamp value was encountered in a context that
+        cannot handle it.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+  </sect2>
+
+   <sect2 id="ecpg-pgtypes-constants">
+    <title>Special Constants of pgtypeslib</title>
+   <para>
+    <variablelist>
+     <varlistentry id="pgtypesinvalidtimestamp">
+      <term><literal>PGTYPESInvalidTimestamp</literal></term>
+      <listitem>
+       <para>
+        A value of type timestamp representing an invalid time stamp. This is
+        returned by the function <function>PGTYPEStimestamp_from_asc</function> on
+        parse error.
+        Note that due to the internal representation of the <type>timestamp</type> data type,
+        <literal>PGTYPESInvalidTimestamp</literal> is also a valid timestamp at
+        the same time. It is set to <literal>1899-12-31 23:59:59</literal>. In order
+        to detect errors, make sure that your application does not only test
+        for <literal>PGTYPESInvalidTimestamp</literal> but also for
+        <literal>errno != 0</literal> after each call to
+        <function>PGTYPEStimestamp_from_asc</function>.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+  </sect2>
+ </sect1>
+
+ <sect1 id="ecpg-descriptors">
+  <title>Using Descriptor Areas</title>
+
+  <para>
+   An SQL descriptor area is a more sophisticated method for processing
+   the result of a <command>SELECT</command>, <command>FETCH</command> or
+   a <command>DESCRIBE</command> statement. An SQL descriptor area groups
+   the data of one row of data together with metadata items into one
+   data structure.  The metadata is particularly useful when executing
+   dynamic SQL statements, where the nature of the result columns might
+   not be known ahead of time. PostgreSQL provides two ways to use
+   Descriptor Areas: the named SQL Descriptor Areas and the C-structure
+   SQLDAs.
+  </para>
+
+  <sect2 id="ecpg-named-descriptors">
+   <title>Named SQL Descriptor Areas</title>
+
+   <para>
+    A named SQL descriptor area consists of a header, which contains
+    information concerning the entire descriptor, and one or more item
+    descriptor areas, which basically each describe one column in the
+    result row.
+   </para>
+
+   <para>
+    Before you can use an SQL descriptor area, you need to allocate one:
+<programlisting>
+EXEC SQL ALLOCATE DESCRIPTOR <replaceable>identifier</replaceable>;
+</programlisting>
+    The identifier serves as the <quote>variable name</quote> of the
+    descriptor area.  <!-- The scope of the allocated descriptor is WHAT?. -->
+    When you don't need the descriptor anymore, you should deallocate
+    it:
+<programlisting>
+EXEC SQL DEALLOCATE DESCRIPTOR <replaceable>identifier</replaceable>;
+</programlisting>
+   </para>
+
+   <para>
+    To use a descriptor area, specify it as the storage target in an
+    <literal>INTO</literal> clause, instead of listing host variables:
+<programlisting>
+EXEC SQL FETCH NEXT FROM mycursor INTO SQL DESCRIPTOR mydesc;
+</programlisting>
+    If the result set is empty, the Descriptor Area will still contain
+    the metadata from the query, i.e., the field names.
+   </para>
+
+   <para>
+    For not yet executed prepared queries, the <command>DESCRIBE</command>
+    statement can be used to get the metadata of the result set:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+char *sql_stmt = "SELECT * FROM table1";
+EXEC SQL END DECLARE SECTION;
+
+EXEC SQL PREPARE stmt1 FROM :sql_stmt;
+EXEC SQL DESCRIBE stmt1 INTO SQL DESCRIPTOR mydesc;
+</programlisting>
+   </para>
+
+   <para>
+    Before PostgreSQL 9.0, the <literal>SQL</literal> keyword was optional,
+    so using <literal>DESCRIPTOR</literal> and <literal>SQL DESCRIPTOR</literal>
+    produced named SQL Descriptor Areas. Now it is mandatory, omitting
+    the <literal>SQL</literal> keyword produces SQLDA Descriptor Areas,
+    see <xref linkend="ecpg-sqlda-descriptors"/>.
+   </para>
+
+   <para>
+    In <command>DESCRIBE</command> and <command>FETCH</command> statements,
+    the <literal>INTO</literal> and <literal>USING</literal> keywords can be
+    used to similarly: they produce the result set and the metadata in a
+    Descriptor Area.
+   </para>
+
+   <para>
+    Now how do you get the data out of the descriptor area?  You can
+    think of the descriptor area as a structure with named fields.  To
+    retrieve the value of a field from the header and store it into a
+    host variable, use the following command:
+<programlisting>
+EXEC SQL GET DESCRIPTOR <replaceable>name</replaceable> :<replaceable>hostvar</replaceable> = <replaceable>field</replaceable>;
+</programlisting>
+    Currently, there is only one header field defined:
+    <replaceable>COUNT</replaceable>, which tells how many item
+    descriptor areas exist (that is, how many columns are contained in
+    the result).  The host variable needs to be of an integer type.  To
+    get a field from the item descriptor area, use the following
+    command:
+<programlisting>
+EXEC SQL GET DESCRIPTOR <replaceable>name</replaceable> VALUE <replaceable>num</replaceable> :<replaceable>hostvar</replaceable> = <replaceable>field</replaceable>;
+</programlisting>
+    <replaceable>num</replaceable> can be a literal integer or a host
+    variable containing an integer. Possible fields are:
+
+    <variablelist>
+     <varlistentry id="ecpg-named-descriptors-cardinality">
+      <term><literal>CARDINALITY</literal> (integer)</term>
+      <listitem>
+       <para>
+        number of rows in the result set
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-data">
+      <term><literal>DATA</literal></term>
+      <listitem>
+       <para>
+        actual data item (therefore, the data type of this field
+        depends on the query)
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-datetime-interval-code">
+      <term><literal>DATETIME_INTERVAL_CODE</literal> (integer)</term>
+      <listitem>
+       <para>
+        When <literal>TYPE</literal> is <literal>9</literal>,
+        <literal>DATETIME_INTERVAL_CODE</literal> will have a value of
+        <literal>1</literal> for <literal>DATE</literal>,
+        <literal>2</literal> for <literal>TIME</literal>,
+        <literal>3</literal> for <literal>TIMESTAMP</literal>,
+        <literal>4</literal> for <literal>TIME WITH TIME ZONE</literal>, or
+        <literal>5</literal> for <literal>TIMESTAMP WITH TIME ZONE</literal>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-datetime-interval-precision">
+      <term><literal>DATETIME_INTERVAL_PRECISION</literal> (integer)</term>
+      <listitem>
+       <para>
+        not implemented
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-indicator">
+      <term><literal>INDICATOR</literal> (integer)</term>
+      <listitem>
+       <para>
+        the indicator (indicating a null value or a value truncation)
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-key-member">
+      <term><literal>KEY_MEMBER</literal> (integer)</term>
+      <listitem>
+       <para>
+        not implemented
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-length">
+      <term><literal>LENGTH</literal> (integer)</term>
+      <listitem>
+       <para>
+        length of the datum in characters
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-name">
+      <term><literal>NAME</literal> (string)</term>
+      <listitem>
+       <para>
+        name of the column
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-nullable">
+      <term><literal>NULLABLE</literal> (integer)</term>
+      <listitem>
+       <para>
+        not implemented
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-octet-length">
+      <term><literal>OCTET_LENGTH</literal> (integer)</term>
+      <listitem>
+       <para>
+        length of the character representation of the datum in bytes
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-precision">
+      <term><literal>PRECISION</literal> (integer)</term>
+      <listitem>
+       <para>
+        precision (for type <type>numeric</type>)
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-returned-length">
+      <term><literal>RETURNED_LENGTH</literal> (integer)</term>
+      <listitem>
+       <para>
+        length of the datum in characters
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-returned-octet-length">
+      <term><literal>RETURNED_OCTET_LENGTH</literal> (integer)</term>
+      <listitem>
+       <para>
+        length of the character representation of the datum in bytes
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-scale">
+      <term><literal>SCALE</literal> (integer)</term>
+      <listitem>
+       <para>
+        scale (for type <type>numeric</type>)
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-named-descriptors-type">
+      <term><literal>TYPE</literal> (integer)</term>
+      <listitem>
+       <para>
+        numeric code of the data type of the column
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+
+   <para>
+    In <command>EXECUTE</command>, <command>DECLARE</command> and <command>OPEN</command>
+    statements, the effect of the <literal>INTO</literal> and <literal>USING</literal>
+    keywords are different. A Descriptor Area can also be manually built to
+    provide the input parameters for a query or a cursor and
+    <literal>USING SQL DESCRIPTOR <replaceable>name</replaceable></literal>
+    is the way to pass the input parameters into a parameterized query. The statement
+    to build a named SQL Descriptor Area is below:
+<programlisting>
+EXEC SQL SET DESCRIPTOR <replaceable>name</replaceable> VALUE <replaceable>num</replaceable> <replaceable>field</replaceable> = :<replaceable>hostvar</replaceable>;
+</programlisting>
+   </para>
+
+   <para>
+    PostgreSQL supports retrieving more that one record in one <command>FETCH</command>
+    statement and storing the data in host variables in this case assumes that the
+    variable is an array. E.g.:
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+int id[5];
+EXEC SQL END DECLARE SECTION;
+
+EXEC SQL FETCH 5 FROM mycursor INTO SQL DESCRIPTOR mydesc;
+
+EXEC SQL GET DESCRIPTOR mydesc VALUE 1 :id = DATA;
+</programlisting>
+
+   </para>
+
+  </sect2>
+
+  <sect2 id="ecpg-sqlda-descriptors">
+   <title>SQLDA Descriptor Areas</title>
+
+   <para>
+    An SQLDA Descriptor Area is a C language structure which can be also used
+    to get the result set and the metadata of a query. One structure stores one
+    record from the result set.
+<programlisting>
+EXEC SQL include sqlda.h;
+sqlda_t         *mysqlda;
+
+EXEC SQL FETCH 3 FROM mycursor INTO DESCRIPTOR mysqlda;
+</programlisting>
+    Note that the <literal>SQL</literal> keyword is omitted. The paragraphs about
+    the use cases of the <literal>INTO</literal> and <literal>USING</literal>
+    keywords in <xref linkend="ecpg-named-descriptors"/> also apply here with an addition.
+    In a <command>DESCRIBE</command> statement the <literal>DESCRIPTOR</literal>
+    keyword can be completely omitted if the <literal>INTO</literal> keyword is used:
+<programlisting>
+EXEC SQL DESCRIBE prepared_statement INTO mysqlda;
+</programlisting>
+   </para>
+
+    <procedure>
+     <para>
+      The general flow of a program that uses SQLDA is:
+     </para>
+     <step><simpara>Prepare a query, and declare a cursor for it.</simpara></step>
+     <step><simpara>Declare an SQLDA for the result rows.</simpara></step>
+     <step><simpara>Declare an SQLDA for the input parameters, and initialize them (memory allocation, parameter settings).</simpara></step>
+     <step><simpara>Open a cursor with the input SQLDA.</simpara></step>
+     <step><simpara>Fetch rows from the cursor, and store them into an output SQLDA.</simpara></step>
+     <step><simpara>Read values from the output SQLDA into the host variables (with conversion if necessary).</simpara></step>
+     <step><simpara>Close the cursor.</simpara></step>
+     <step><simpara>Free the memory area allocated for the input SQLDA.</simpara></step>
+    </procedure>
+
+   <sect3 id="ecpg-sqlda-descriptors-sqlda">
+    <title>SQLDA Data Structure</title>
+
+    <para>
+     SQLDA uses three data structure
+     types: <type>sqlda_t</type>, <type>sqlvar_t</type>,
+     and <type>struct sqlname</type>.
+    </para>
+
+    <tip>
+     <para>
+      PostgreSQL's SQLDA has a similar data structure to the one in
+      IBM DB2 Universal Database, so some technical information on
+      DB2's SQLDA could help understanding PostgreSQL's one better.
+     </para>
+    </tip>
+
+    <sect4 id="ecpg-sqlda-sqlda">
+     <title>sqlda_t Structure</title>
+
+     <para>
+      The structure type <type>sqlda_t</type> is the type of the
+      actual SQLDA.  It holds one record.  And two or
+      more <type>sqlda_t</type> structures can be connected in a
+      linked list with the pointer in
+      the <structfield>desc_next</structfield> field, thus
+      representing an ordered collection of rows.  So, when two or
+      more rows are fetched, the application can read them by
+      following the <structfield>desc_next</structfield> pointer in
+      each <type>sqlda_t</type> node.
+     </para>
+
+     <para>
+      The definition of <type>sqlda_t</type> is:
+<programlisting>
+struct sqlda_struct
+{
+    char            sqldaid[8];
+    long            sqldabc;
+    short           sqln;
+    short           sqld;
+    struct sqlda_struct *desc_next;
+    struct sqlvar_struct sqlvar[1];
+};
+
+typedef struct sqlda_struct sqlda_t;
+</programlisting>
+
+      The meaning of the fields is:
+
+    <variablelist>
+     <varlistentry id="ecpg-sqlda-sqlda-sqldaid">
+      <term><literal>sqldaid</literal></term>
+      <listitem>
+       <para>
+        It contains the literal string <literal>"SQLDA  "</literal>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sqlda-sqlda-sqldabc">
+      <term><literal>sqldabc</literal></term>
+      <listitem>
+       <para>
+        It contains the size of the allocated space in bytes.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sqlda-sqlda-sqln">
+      <term><literal>sqln</literal></term>
+      <listitem>
+       <para>
+        It contains the number of input parameters for a parameterized query in
+        case it's passed into <command>OPEN</command>, <command>DECLARE</command> or
+        <command>EXECUTE</command> statements using the <literal>USING</literal>
+        keyword. In case it's used as output of <command>SELECT</command>,
+        <command>EXECUTE</command> or <command>FETCH</command> statements,
+        its value is the same as <literal>sqld</literal>
+        statement
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sqlda-sqlda-sqld">
+      <term><literal>sqld</literal></term>
+      <listitem>
+       <para>
+        It contains the number of fields in a result set.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sqlda-sqlda-desc-next">
+      <term><literal>desc_next</literal></term>
+      <listitem>
+       <para>
+        If the query returns more than one record, multiple linked
+        SQLDA structures are returned, and <literal>desc_next</literal> holds
+        a pointer to the next entry in the list.
+       </para>
+      </listitem>
+     </varlistentry>
+     <varlistentry id="ecpg-sqlda-sqlda-sqlvar">
+      <term><literal>sqlvar</literal></term>
+      <listitem>
+       <para>
+        This is the array of the columns in the result set.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+     </para>
+    </sect4>
+
+    <sect4 id="ecpg-sqlda-sqlvar">
+     <title>sqlvar_t Structure</title>
+
+     <para>
+      The structure type <type>sqlvar_t</type> holds a column value
+      and metadata such as type and length. The definition of the type
+      is:
+
+<programlisting>
+struct sqlvar_struct
+{
+    short          sqltype;
+    short          sqllen;
+    char          *sqldata;
+    short         *sqlind;
+    struct sqlname sqlname;
+};
+
+typedef struct sqlvar_struct sqlvar_t;
+</programlisting>
+
+      The meaning of the fields is:
+
+        <variablelist>
+         <varlistentry id="ecpg-sqlda-sqlvar-sqltype">
+         <term><literal>sqltype</literal></term>
+          <listitem>
+           <para>
+            Contains the type identifier of the field. For values,
+            see <literal>enum ECPGttype</literal> in <literal>ecpgtype.h</literal>.
+           </para>
+          </listitem>
+         </varlistentry>
+
+         <varlistentry id="ecpg-sqlda-sqlvar-sqllen">
+         <term><literal>sqllen</literal></term>
+          <listitem>
+           <para>
+            Contains the binary length of the field. e.g., 4 bytes for <type>ECPGt_int</type>.
+           </para>
+          </listitem>
+         </varlistentry>
+
+         <varlistentry id="ecpg-sqlda-sqlvar-sqldata">
+         <term><literal>sqldata</literal></term>
+          <listitem>
+           <para>
+            Points to the data.  The format of the data is described
+            in <xref linkend="ecpg-variables-type-mapping"/>.
+           </para>
+          </listitem>
+         </varlistentry>
+
+         <varlistentry id="ecpg-sqlda-sqlvar-sqlind">
+         <term><literal>sqlind</literal></term>
+          <listitem>
+           <para>
+            Points to the null indicator.  0 means not null, -1 means
+            null.
+           </para>
+          </listitem>
+         </varlistentry>
+
+         <varlistentry id="ecpg-sqlda-sqlvar-sqlname">
+         <term><literal>sqlname</literal></term>
+          <listitem>
+           <para>
+            The name of the field.
+           </para>
+          </listitem>
+         </varlistentry>
+        </variablelist>
+     </para>
+    </sect4>
+
+    <sect4 id="ecpg-sqlda-sqlname">
+     <title>struct sqlname Structure</title>
+
+     <para>
+      A <type>struct sqlname</type> structure holds a column name.  It
+      is used as a member of the <type>sqlvar_t</type> structure.  The
+      definition of the structure is:
+<programlisting>
+#define NAMEDATALEN 64
+
+struct sqlname
+{
+        short           length;
+        char            data[NAMEDATALEN];
+};
+</programlisting>
+      The meaning of the fields is:
+            <variablelist>
+             <varlistentry id="ecpg-sqlda-sqlname-length">
+              <term><literal>length</literal></term>
+               <listitem>
+                <para>
+                 Contains the length of the field name.
+                </para>
+               </listitem>
+              </varlistentry>
+             <varlistentry id="ecpg-sqlda-sqlname-data">
+              <term><literal>data</literal></term>
+               <listitem>
+                <para>
+                 Contains the actual field name.
+                </para>
+               </listitem>
+              </varlistentry>
+            </variablelist>
+     </para>
+    </sect4>
+   </sect3>
+
+   <sect3 id="ecpg-sqlda-output">
+    <title>Retrieving a Result Set Using an SQLDA</title>
+
+    <procedure>
+     <para>
+      The general steps to retrieve a query result set through an
+      SQLDA are:
+     </para>
+     <step><simpara>Declare an <type>sqlda_t</type> structure to receive the result set.</simpara></step>
+     <step><simpara>Execute <command>FETCH</command>/<command>EXECUTE</command>/<command>DESCRIBE</command> commands to process a query specifying the declared SQLDA.</simpara></step>
+     <step><simpara>Check the number of records in the result set by looking at <structfield>sqln</structfield>, a member of the <type>sqlda_t</type> structure.</simpara></step>
+     <step><simpara>Get the values of each column from <literal>sqlvar[0]</literal>, <literal>sqlvar[1]</literal>, etc., members of the <type>sqlda_t</type> structure.</simpara></step>
+     <step><simpara>Go to next row (<type>sqlda_t</type> structure) by following the <structfield>desc_next</structfield> pointer, a member of the <type>sqlda_t</type> structure.</simpara></step>
+     <step><simpara>Repeat above as you need.</simpara></step>
+    </procedure>
+
+    <para>
+     Here is an example retrieving a result set through an SQLDA.
+    </para>
+
+    <para>
+     First, declare a <type>sqlda_t</type> structure to receive the result set.
+<programlisting>
+sqlda_t *sqlda1;
+</programlisting>
+    </para>
+
+    <para>
+     Next, specify the SQLDA in a command.  This is
+     a <command>FETCH</command> command example.
+<programlisting>
+EXEC SQL FETCH NEXT FROM cur1 INTO DESCRIPTOR sqlda1;
+</programlisting>
+    </para>
+
+    <para>
+     Run a loop following the linked list to retrieve the rows.
+<programlisting>
+sqlda_t *cur_sqlda;
+
+for (cur_sqlda = sqlda1;
+     cur_sqlda != NULL;
+     cur_sqlda = cur_sqlda->desc_next)
+{
+    ...
+}
+</programlisting>
+    </para>
+
+    <para>
+     Inside the loop, run another loop to retrieve each column data
+     (<type>sqlvar_t</type> structure) of the row.
+<programlisting>
+for (i = 0; i &lt; cur_sqlda->sqld; i++)
+{
+    sqlvar_t v = cur_sqlda->sqlvar[i];
+    char *sqldata = v.sqldata;
+    short sqllen  = v.sqllen;
+    ...
+}
+</programlisting>
+    </para>
+
+    <para>
+     To get a column value, check the <structfield>sqltype</structfield> value,
+     a member of the <type>sqlvar_t</type> structure.  Then, switch
+     to an appropriate way, depending on the column type, to copy
+     data from the <structfield>sqlvar</structfield> field to a host variable.
+<programlisting>
+char var_buf[1024];
+
+switch (v.sqltype)
+{
+    case ECPGt_char:
+        memset(&amp;var_buf, 0, sizeof(var_buf));
+        memcpy(&amp;var_buf, sqldata, (sizeof(var_buf) &lt;= sqllen ? sizeof(var_buf) - 1 : sqllen));
+        break;
+
+    case ECPGt_int: /* integer */
+        memcpy(&amp;intval, sqldata, sqllen);
+        snprintf(var_buf, sizeof(var_buf), "%d", intval);
+        break;
+
+    ...
+}
+</programlisting>
+    </para>
+   </sect3>
+
+   <sect3 id="ecpg-sqlda-input">
+    <title>Passing Query Parameters Using an SQLDA</title>
+
+    <procedure>
+     <para>
+      The general steps to use an SQLDA to pass input
+      parameters to a prepared query are:
+     </para>
+     <step><simpara>Create a prepared query (prepared statement)</simpara></step>
+     <step><simpara>Declare an sqlda_t structure as an input SQLDA.</simpara></step>
+     <step><simpara>Allocate memory area (as sqlda_t structure) for the input SQLDA.</simpara></step>
+     <step><simpara>Set (copy) input values in the allocated memory.</simpara></step>
+     <step><simpara>Open a cursor with specifying the input SQLDA.</simpara></step>
+    </procedure>
+
+    <para>
+     Here is an example.
+    </para>
+
+    <para>
+     First, create a prepared statement.
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+char query[1024] = "SELECT d.oid, * FROM pg_database d, pg_stat_database s WHERE d.oid = s.datid AND (d.datname = ? OR d.oid = ?)";
+EXEC SQL END DECLARE SECTION;
+
+EXEC SQL PREPARE stmt1 FROM :query;
+</programlisting>
+    </para>
+
+    <para>
+     Next, allocate memory for an SQLDA, and set the number of input
+     parameters in <structfield>sqln</structfield>, a member variable of
+     the <type>sqlda_t</type> structure.  When two or more input
+     parameters are required for the prepared query, the application
+     has to allocate additional memory space which is calculated by
+     (nr. of params - 1) * sizeof(sqlvar_t).  The example shown here
+     allocates memory space for two input parameters.
+<programlisting>
+sqlda_t *sqlda2;
+
+sqlda2 = (sqlda_t *) malloc(sizeof(sqlda_t) + sizeof(sqlvar_t));
+memset(sqlda2, 0, sizeof(sqlda_t) + sizeof(sqlvar_t));
+
+sqlda2->sqln = 2; /* number of input variables */
+</programlisting>
+    </para>
+
+    <para>
+     After memory allocation, store the parameter values into the
+     <literal>sqlvar[]</literal> array.  (This is same array used for
+     retrieving column values when the SQLDA is receiving a result
+     set.)  In this example, the input parameters
+     are <literal>"postgres"</literal>, having a string type,
+     and <literal>1</literal>, having an integer type.
+<programlisting>
+sqlda2->sqlvar[0].sqltype = ECPGt_char;
+sqlda2->sqlvar[0].sqldata = "postgres";
+sqlda2->sqlvar[0].sqllen  = 8;
+
+int intval = 1;
+sqlda2->sqlvar[1].sqltype = ECPGt_int;
+sqlda2->sqlvar[1].sqldata = (char *) &amp;intval;
+sqlda2->sqlvar[1].sqllen  = sizeof(intval);
+</programlisting>
+    </para>
+
+    <para>
+     By opening a cursor and specifying the SQLDA that was set up
+     beforehand, the input parameters are passed to the prepared
+     statement.
+<programlisting>
+EXEC SQL OPEN cur1 USING DESCRIPTOR sqlda2;
+</programlisting>
+    </para>
+
+    <para>
+     Finally, after using input SQLDAs, the allocated memory space
+     must be freed explicitly, unlike SQLDAs used for receiving query
+     results.
+<programlisting>
+free(sqlda2);
+</programlisting>
+    </para>
+   </sect3>
+
+   <sect3 id="ecpg-sqlda-example">
+    <title>A Sample Application Using SQLDA</title>
+
+    <para>
+     Here is an example program, which describes how to fetch access
+     statistics of the databases, specified by the input parameters,
+     from the system catalogs.
+    </para>
+
+    <para>
+     This application joins two system tables, pg_database and
+     pg_stat_database on the database OID, and also fetches and shows
+     the database statistics which are retrieved by two input
+     parameters (a database <literal>postgres</literal>, and OID <literal>1</literal>).
+    </para>
+
+    <para>
+     First, declare an SQLDA for input and an SQLDA for output.
+<programlisting>
+EXEC SQL include sqlda.h;
+
+sqlda_t *sqlda1; /* an output descriptor */
+sqlda_t *sqlda2; /* an input descriptor  */
+</programlisting>
+    </para>
+
+    <para>
+     Next, connect to the database, prepare a statement, and declare a
+     cursor for the prepared statement.
+<programlisting>
+int
+main(void)
+{
+    EXEC SQL BEGIN DECLARE SECTION;
+    char query[1024] = "SELECT d.oid,* FROM pg_database d, pg_stat_database s WHERE d.oid=s.datid AND ( d.datname=? OR d.oid=? )";
+    EXEC SQL END DECLARE SECTION;
+
+    EXEC SQL CONNECT TO testdb AS con1 USER testuser;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+
+    EXEC SQL PREPARE stmt1 FROM :query;
+    EXEC SQL DECLARE cur1 CURSOR FOR stmt1;
+</programlisting>
+    </para>
+
+    <para>
+     Next, put some values in the input SQLDA for the input
+     parameters.  Allocate memory for the input SQLDA, and set the
+     number of input parameters to <literal>sqln</literal>.  Store
+     type, value, and value length into <literal>sqltype</literal>,
+     <literal>sqldata</literal>, and <literal>sqllen</literal> in the
+     <literal>sqlvar</literal> structure.
+
+<programlisting>
+    /* Create SQLDA structure for input parameters. */
+    sqlda2 = (sqlda_t *) malloc(sizeof(sqlda_t) + sizeof(sqlvar_t));
+    memset(sqlda2, 0, sizeof(sqlda_t) + sizeof(sqlvar_t));
+    sqlda2->sqln = 2; /* number of input variables */
+
+    sqlda2->sqlvar[0].sqltype = ECPGt_char;
+    sqlda2->sqlvar[0].sqldata = "postgres";
+    sqlda2->sqlvar[0].sqllen  = 8;
+
+    intval = 1;
+    sqlda2->sqlvar[1].sqltype = ECPGt_int;
+    sqlda2->sqlvar[1].sqldata = (char *)&amp;intval;
+    sqlda2->sqlvar[1].sqllen  = sizeof(intval);
+</programlisting>
+    </para>
+
+    <para>
+     After setting up the input SQLDA, open a cursor with the input
+     SQLDA.
+
+<programlisting>
+    /* Open a cursor with input parameters. */
+    EXEC SQL OPEN cur1 USING DESCRIPTOR sqlda2;
+</programlisting>
+    </para>
+
+    <para>
+     Fetch rows into the output SQLDA from the opened cursor.
+     (Generally, you have to call <command>FETCH</command> repeatedly
+     in the loop, to fetch all rows in the result set.)
+<programlisting>
+    while (1)
+    {
+        sqlda_t *cur_sqlda;
+
+        /* Assign descriptor to the cursor  */
+        EXEC SQL FETCH NEXT FROM cur1 INTO DESCRIPTOR sqlda1;
+</programlisting>
+    </para>
+
+    <para>
+     Next, retrieve the fetched records from the SQLDA, by following
+     the linked list of the <type>sqlda_t</type> structure.
+<programlisting>
+    for (cur_sqlda = sqlda1 ;
+         cur_sqlda != NULL ;
+         cur_sqlda = cur_sqlda->desc_next)
+    {
+        ...
+</programlisting>
+    </para>
+
+    <para>
+     Read each columns in the first record.  The number of columns is
+     stored in <structfield>sqld</structfield>, the actual data of the first
+     column is stored in <literal>sqlvar[0]</literal>, both members of
+     the <type>sqlda_t</type> structure.
+
+<programlisting>
+        /* Print every column in a row. */
+        for (i = 0; i &lt; sqlda1-&gt;sqld; i++)
+        {
+            sqlvar_t v = sqlda1->sqlvar[i];
+            char *sqldata = v.sqldata;
+            short sqllen  = v.sqllen;
+
+            strncpy(name_buf, v.sqlname.data, v.sqlname.length);
+            name_buf[v.sqlname.length] = '\0';
+</programlisting>
+    </para>
+
+    <para>
+     Now, the column data is stored in the variable <varname>v</varname>.
+     Copy every datum into host variables, looking
+     at <literal>v.sqltype</literal> for the type of the column.
+<programlisting>
+            switch (v.sqltype) {
+                int intval;
+                double doubleval;
+                unsigned long long int longlongval;
+
+                case ECPGt_char:
+                    memset(&amp;var_buf, 0, sizeof(var_buf));
+                    memcpy(&amp;var_buf, sqldata, (sizeof(var_buf) &lt;= sqllen ? sizeof(var_buf)-1 : sqllen));
+                    break;
+
+                case ECPGt_int: /* integer */
+                    memcpy(&amp;intval, sqldata, sqllen);
+                    snprintf(var_buf, sizeof(var_buf), "%d", intval);
+                    break;
+
+                ...
+
+                default:
+                    ...
+            }
+
+            printf("%s = %s (type: %d)\n", name_buf, var_buf, v.sqltype);
+        }
+</programlisting>
+    </para>
+
+    <para>
+     Close the cursor after processing all of records, and disconnect
+     from the database.
+<programlisting>
+    EXEC SQL CLOSE cur1;
+    EXEC SQL COMMIT;
+
+    EXEC SQL DISCONNECT ALL;
+</programlisting>
+    </para>
+
+    <para>
+     The whole program is shown
+     in <xref linkend="ecpg-sqlda-example-example"/>.
+    </para>
+
+    <example id="ecpg-sqlda-example-example">
+     <title>Example SQLDA Program</title>
+<programlisting>
+#include &lt;stdlib.h>
+#include &lt;string.h>
+#include &lt;stdlib.h>
+#include &lt;stdio.h>
+#include &lt;unistd.h>
+
+EXEC SQL include sqlda.h;
+
+sqlda_t *sqlda1; /* descriptor for output */
+sqlda_t *sqlda2; /* descriptor for input */
+
+EXEC SQL WHENEVER NOT FOUND DO BREAK;
+EXEC SQL WHENEVER SQLERROR STOP;
+
+int
+main(void)
+{
+    EXEC SQL BEGIN DECLARE SECTION;
+    char query[1024] = "SELECT d.oid,* FROM pg_database d, pg_stat_database s WHERE d.oid=s.datid AND ( d.datname=? OR d.oid=? )";
+
+    int intval;
+    unsigned long long int longlongval;
+    EXEC SQL END DECLARE SECTION;
+
+    EXEC SQL CONNECT TO uptimedb AS con1 USER uptime;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+
+    EXEC SQL PREPARE stmt1 FROM :query;
+    EXEC SQL DECLARE cur1 CURSOR FOR stmt1;
+
+    /* Create an SQLDA structure for an input parameter */
+    sqlda2 = (sqlda_t *)malloc(sizeof(sqlda_t) + sizeof(sqlvar_t));
+    memset(sqlda2, 0, sizeof(sqlda_t) + sizeof(sqlvar_t));
+    sqlda2->sqln = 2; /* a number of input variables */
+
+    sqlda2->sqlvar[0].sqltype = ECPGt_char;
+    sqlda2->sqlvar[0].sqldata = "postgres";
+    sqlda2->sqlvar[0].sqllen  = 8;
+
+    intval = 1;
+    sqlda2->sqlvar[1].sqltype = ECPGt_int;
+    sqlda2->sqlvar[1].sqldata = (char *) &amp;intval;
+    sqlda2->sqlvar[1].sqllen  = sizeof(intval);
+
+    /* Open a cursor with input parameters. */
+    EXEC SQL OPEN cur1 USING DESCRIPTOR sqlda2;
+
+    while (1)
+    {
+        sqlda_t *cur_sqlda;
+
+        /* Assign descriptor to the cursor  */
+        EXEC SQL FETCH NEXT FROM cur1 INTO DESCRIPTOR sqlda1;
+
+        for (cur_sqlda = sqlda1 ;
+             cur_sqlda != NULL ;
+             cur_sqlda = cur_sqlda->desc_next)
+        {
+            int i;
+            char name_buf[1024];
+            char var_buf[1024];
+
+            /* Print every column in a row. */
+            for (i=0 ; i&lt;cur_sqlda->sqld ; i++)
+            {
+                sqlvar_t v = cur_sqlda->sqlvar[i];
+                char *sqldata = v.sqldata;
+                short sqllen  = v.sqllen;
+
+                strncpy(name_buf, v.sqlname.data, v.sqlname.length);
+                name_buf[v.sqlname.length] = '\0';
+
+                switch (v.sqltype)
+                {
+                    case ECPGt_char:
+                        memset(&amp;var_buf, 0, sizeof(var_buf));
+                        memcpy(&amp;var_buf, sqldata, (sizeof(var_buf)&lt;=sqllen ? sizeof(var_buf)-1 : sqllen) );
+                        break;
+
+                    case ECPGt_int: /* integer */
+                        memcpy(&amp;intval, sqldata, sqllen);
+                        snprintf(var_buf, sizeof(var_buf), "%d", intval);
+                        break;
+
+                    case ECPGt_long_long: /* bigint */
+                        memcpy(&amp;longlongval, sqldata, sqllen);
+                        snprintf(var_buf, sizeof(var_buf), "%lld", longlongval);
+                        break;
+
+                    default:
+                    {
+                        int i;
+                        memset(var_buf, 0, sizeof(var_buf));
+                        for (i = 0; i &lt; sqllen; i++)
+                        {
+                            char tmpbuf[16];
+                            snprintf(tmpbuf, sizeof(tmpbuf), "%02x ", (unsigned char) sqldata[i]);
+                            strncat(var_buf, tmpbuf, sizeof(var_buf));
+                        }
+                    }
+                        break;
+                }
+
+                printf("%s = %s (type: %d)\n", name_buf, var_buf, v.sqltype);
+            }
+
+            printf("\n");
+        }
+    }
+
+    EXEC SQL CLOSE cur1;
+    EXEC SQL COMMIT;
+
+    EXEC SQL DISCONNECT ALL;
+
+    return 0;
+}
+</programlisting>
+
+     <para>
+      The output of this example should look something like the
+      following (some numbers will vary).
+     </para>
+
+<screen>
+oid = 1 (type: 1)
+datname = template1 (type: 1)
+datdba = 10 (type: 1)
+encoding = 0 (type: 5)
+datistemplate = t (type: 1)
+datallowconn = t (type: 1)
+datconnlimit = -1 (type: 5)
+datfrozenxid = 379 (type: 1)
+dattablespace = 1663 (type: 1)
+datconfig =  (type: 1)
+datacl = {=c/uptime,uptime=CTc/uptime} (type: 1)
+datid = 1 (type: 1)
+datname = template1 (type: 1)
+numbackends = 0 (type: 5)
+xact_commit = 113606 (type: 9)
+xact_rollback = 0 (type: 9)
+blks_read = 130 (type: 9)
+blks_hit = 7341714 (type: 9)
+tup_returned = 38262679 (type: 9)
+tup_fetched = 1836281 (type: 9)
+tup_inserted = 0 (type: 9)
+tup_updated = 0 (type: 9)
+tup_deleted = 0 (type: 9)
+
+oid = 11511 (type: 1)
+datname = postgres (type: 1)
+datdba = 10 (type: 1)
+encoding = 0 (type: 5)
+datistemplate = f (type: 1)
+datallowconn = t (type: 1)
+datconnlimit = -1 (type: 5)
+datfrozenxid = 379 (type: 1)
+dattablespace = 1663 (type: 1)
+datconfig =  (type: 1)
+datacl =  (type: 1)
+datid = 11511 (type: 1)
+datname = postgres (type: 1)
+numbackends = 0 (type: 5)
+xact_commit = 221069 (type: 9)
+xact_rollback = 18 (type: 9)
+blks_read = 1176 (type: 9)
+blks_hit = 13943750 (type: 9)
+tup_returned = 77410091 (type: 9)
+tup_fetched = 3253694 (type: 9)
+tup_inserted = 0 (type: 9)
+tup_updated = 0 (type: 9)
+tup_deleted = 0 (type: 9)
+</screen>
+    </example>
+   </sect3>
+  </sect2>
+ </sect1>
+
+ <sect1 id="ecpg-errors">
+  <title>Error Handling</title>
+
+  <para>
+   This section describes how you can handle exceptional conditions
+   and warnings in an embedded SQL program.  There are two
+   nonexclusive facilities for this.
+
+   <itemizedlist>
+    <listitem>
+     <simpara>
+      Callbacks can be configured to handle warning and error
+      conditions using the <literal>WHENEVER</literal> command.
+     </simpara>
+    </listitem>
+
+    <listitem>
+     <simpara>
+      Detailed information about the error or warning can be obtained
+      from the <varname>sqlca</varname> variable.
+     </simpara>
+    </listitem>
+   </itemizedlist>
+  </para>
+
+  <sect2 id="ecpg-whenever">
+   <title>Setting Callbacks</title>
+
+   <para>
+    One simple method to catch errors and warnings is to set a
+    specific action to be executed whenever a particular condition
+    occurs.  In general:
+<programlisting>
+EXEC SQL WHENEVER <replaceable>condition</replaceable> <replaceable>action</replaceable>;
+</programlisting>
+   </para>
+
+   <para>
+    <replaceable>condition</replaceable> can be one of the following:
+
+    <variablelist>
+     <varlistentry id="ecpg-whenever-sqlerror">
+      <term><literal>SQLERROR</literal></term>
+      <listitem>
+       <para>
+        The specified action is called whenever an error occurs during
+        the execution of an SQL statement.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-whenever-sqlwarning">
+      <term><literal>SQLWARNING</literal></term>
+      <listitem>
+       <para>
+        The specified action is called whenever a warning occurs
+        during the execution of an SQL statement.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-whenever-not-found">
+      <term><literal>NOT FOUND</literal></term>
+      <listitem>
+       <para>
+        The specified action is called whenever an SQL statement
+        retrieves or affects zero rows.  (This condition is not an
+        error, but you might be interested in handling it specially.)
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+
+   <para>
+    <replaceable>action</replaceable> can be one of the following:
+
+    <variablelist>
+     <varlistentry id="ecpg-whenever-continue">
+      <term><literal>CONTINUE</literal></term>
+      <listitem>
+       <para>
+        This effectively means that the condition is ignored.  This is
+        the default.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-whenever-goto">
+      <term><literal>GOTO <replaceable>label</replaceable></literal></term>
+      <term><literal>GO TO <replaceable>label</replaceable></literal></term>
+      <listitem>
+       <para>
+        Jump to the specified label (using a C <literal>goto</literal>
+        statement).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-whenever-sqlprint">
+      <term><literal>SQLPRINT</literal></term>
+      <listitem>
+       <para>
+        Print a message to standard error.  This is useful for simple
+        programs or during prototyping.  The details of the message
+        cannot be configured.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-whenever-stop">
+      <term><literal>STOP</literal></term>
+      <listitem>
+       <para>
+        Call <literal>exit(1)</literal>, which will terminate the
+        program.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-whenever-do-break">
+      <term><literal>DO BREAK</literal></term>
+      <listitem>
+       <para>
+        Execute the C statement <literal>break</literal>.  This should
+        only be used in loops or <literal>switch</literal> statements.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-whenever-do-continue">
+      <term><literal>DO CONTINUE</literal></term>
+      <listitem>
+       <para>
+        Execute the C statement <literal>continue</literal>.  This should
+        only be used in loops statements.  if executed, will cause the flow
+        of control to return to the top of the loop.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-whenever-call">
+      <term><literal>CALL <replaceable>name</replaceable> (<replaceable>args</replaceable>)</literal></term>
+      <term><literal>DO <replaceable>name</replaceable> (<replaceable>args</replaceable>)</literal></term>
+      <listitem>
+       <para>
+        Call the specified C functions with the specified arguments.  (This
+        use is different from the meaning of <literal>CALL</literal>
+        and <literal>DO</literal> in the normal PostgreSQL grammar.)
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+
+    The SQL standard only provides for the actions
+    <literal>CONTINUE</literal> and <literal>GOTO</literal> (and
+    <literal>GO TO</literal>).
+   </para>
+
+   <para>
+    Here is an example that you might want to use in a simple program.
+    It prints a simple message when a warning occurs and aborts the
+    program when an error happens:
+<programlisting>
+EXEC SQL WHENEVER SQLWARNING SQLPRINT;
+EXEC SQL WHENEVER SQLERROR STOP;
+</programlisting>
+   </para>
+
+   <para>
+    The statement <literal>EXEC SQL WHENEVER</literal> is a directive
+    of the SQL preprocessor, not a C statement.  The error or warning
+    actions that it sets apply to all embedded SQL statements that
+    appear below the point where the handler is set, unless a
+    different action was set for the same condition between the first
+    <literal>EXEC SQL WHENEVER</literal> and the SQL statement causing
+    the condition, regardless of the flow of control in the C program.
+    So neither of the two following C program excerpts will have the
+    desired effect:
+<programlisting>
+/*
+ * WRONG
+ */
+int main(int argc, char *argv[])
+{
+    ...
+    if (verbose) {
+        EXEC SQL WHENEVER SQLWARNING SQLPRINT;
+    }
+    ...
+    EXEC SQL SELECT ...;
+    ...
+}
+</programlisting>
+
+<programlisting>
+/*
+ * WRONG
+ */
+int main(int argc, char *argv[])
+{
+    ...
+    set_error_handler();
+    ...
+    EXEC SQL SELECT ...;
+    ...
+}
+
+static void set_error_handler(void)
+{
+    EXEC SQL WHENEVER SQLERROR STOP;
+}
+</programlisting>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-sqlca">
+   <title>sqlca</title>
+
+   <para>
+    For more powerful error handling, the embedded SQL interface
+    provides a global variable with the name <varname>sqlca</varname>
+    (SQL communication area)
+    that has the following structure:
+<programlisting>
+struct
+{
+    char sqlcaid[8];
+    long sqlabc;
+    long sqlcode;
+    struct
+    {
+        int sqlerrml;
+        char sqlerrmc[SQLERRMC_LEN];
+    } sqlerrm;
+    char sqlerrp[8];
+    long sqlerrd[6];
+    char sqlwarn[8];
+    char sqlstate[5];
+} sqlca;
+</programlisting>
+    (In a multithreaded program, every thread automatically gets its
+    own copy of <varname>sqlca</varname>.  This works similarly to the
+    handling of the standard C global variable
+    <varname>errno</varname>.)
+   </para>
+
+   <para>
+    <varname>sqlca</varname> covers both warnings and errors.  If
+    multiple warnings or errors occur during the execution of a
+    statement, then <varname>sqlca</varname> will only contain
+    information about the last one.
+   </para>
+
+   <para>
+    If no error occurred in the last <acronym>SQL</acronym> statement,
+    <literal>sqlca.sqlcode</literal> will be 0 and
+    <literal>sqlca.sqlstate</literal> will be
+    <literal>"00000"</literal>.  If a warning or error occurred, then
+    <literal>sqlca.sqlcode</literal> will be negative and
+    <literal>sqlca.sqlstate</literal> will be different from
+    <literal>"00000"</literal>.  A positive
+    <literal>sqlca.sqlcode</literal> indicates a harmless condition,
+    such as that the last query returned zero rows.
+    <literal>sqlcode</literal> and <literal>sqlstate</literal> are two
+    different error code schemes; details appear below.
+   </para>
+
+   <para>
+    If the last SQL statement was successful, then
+    <literal>sqlca.sqlerrd[1]</literal> contains the OID of the
+    processed row, if applicable, and
+    <literal>sqlca.sqlerrd[2]</literal> contains the number of
+    processed or returned rows, if applicable to the command.
+   </para>
+
+   <para>
+    In case of an error or warning,
+    <literal>sqlca.sqlerrm.sqlerrmc</literal> will contain a string
+    that describes the error.  The field
+    <literal>sqlca.sqlerrm.sqlerrml</literal> contains the length of
+    the error message that is stored in
+    <literal>sqlca.sqlerrm.sqlerrmc</literal> (the result of
+    <function>strlen()</function>, not really interesting for a C
+    programmer).  Note that some messages are too long to fit in the
+    fixed-size <literal>sqlerrmc</literal> array; they will be truncated.
+   </para>
+
+   <para>
+    In case of a warning, <literal>sqlca.sqlwarn[2]</literal> is set
+    to <literal>W</literal>.  (In all other cases, it is set to
+    something different from <literal>W</literal>.)  If
+    <literal>sqlca.sqlwarn[1]</literal> is set to
+    <literal>W</literal>, then a value was truncated when it was
+    stored in a host variable.  <literal>sqlca.sqlwarn[0]</literal> is
+    set to <literal>W</literal> if any of the other elements are set
+    to indicate a warning.
+   </para>
+
+   <para>
+    The fields <structfield>sqlcaid</structfield>,
+    <structfield>sqlabc</structfield>,
+    <structfield>sqlerrp</structfield>, and the remaining elements of
+    <structfield>sqlerrd</structfield> and
+    <structfield>sqlwarn</structfield> currently contain no useful
+    information.
+   </para>
+
+   <para>
+    The structure <varname>sqlca</varname> is not defined in the SQL
+    standard, but is implemented in several other SQL database
+    systems.  The definitions are similar at the core, but if you want
+    to write portable applications, then you should investigate the
+    different implementations carefully.
+   </para>
+
+   <para>
+    Here is one example that combines the use of <literal>WHENEVER</literal>
+    and <varname>sqlca</varname>, printing out the contents
+    of <varname>sqlca</varname> when an error occurs.  This is perhaps
+    useful for debugging or prototyping applications, before
+    installing a more <quote>user-friendly</quote> error handler.
+
+<programlisting>
+EXEC SQL WHENEVER SQLERROR CALL print_sqlca();
+
+void
+print_sqlca()
+{
+    fprintf(stderr, "==== sqlca ====\n");
+    fprintf(stderr, "sqlcode: %ld\n", sqlca.sqlcode);
+    fprintf(stderr, "sqlerrm.sqlerrml: %d\n", sqlca.sqlerrm.sqlerrml);
+    fprintf(stderr, "sqlerrm.sqlerrmc: %s\n", sqlca.sqlerrm.sqlerrmc);
+    fprintf(stderr, "sqlerrd: %ld %ld %ld %ld %ld %ld\n", sqlca.sqlerrd[0],sqlca.sqlerrd[1],sqlca.sqlerrd[2],
+                                                          sqlca.sqlerrd[3],sqlca.sqlerrd[4],sqlca.sqlerrd[5]);
+    fprintf(stderr, "sqlwarn: %d %d %d %d %d %d %d %d\n", sqlca.sqlwarn[0], sqlca.sqlwarn[1], sqlca.sqlwarn[2],
+                                                          sqlca.sqlwarn[3], sqlca.sqlwarn[4], sqlca.sqlwarn[5],
+                                                          sqlca.sqlwarn[6], sqlca.sqlwarn[7]);
+    fprintf(stderr, "sqlstate: %5s\n", sqlca.sqlstate);
+    fprintf(stderr, "===============\n");
+}
+</programlisting>
+
+    The result could look as follows (here an error due to a
+    misspelled table name):
+
+<screen>
+==== sqlca ====
+sqlcode: -400
+sqlerrm.sqlerrml: 49
+sqlerrm.sqlerrmc: relation "pg_databasep" does not exist on line 38
+sqlerrd: 0 0 0 0 0 0
+sqlwarn: 0 0 0 0 0 0 0 0
+sqlstate: 42P01
+===============
+</screen>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-sqlstate-sqlcode">
+   <title><literal>SQLSTATE</literal> vs. <literal>SQLCODE</literal></title>
+
+   <para>
+    The fields <literal>sqlca.sqlstate</literal> and
+    <literal>sqlca.sqlcode</literal> are two different schemes that
+    provide error codes.  Both are derived from the SQL standard, but
+    <literal>SQLCODE</literal> has been marked deprecated in the SQL-92
+    edition of the standard and has been dropped in later editions.
+    Therefore, new applications are strongly encouraged to use
+    <literal>SQLSTATE</literal>.
+   </para>
+
+   <para>
+    <literal>SQLSTATE</literal> is a five-character array.  The five
+    characters contain digits or upper-case letters that represent
+    codes of various error and warning conditions.
+    <literal>SQLSTATE</literal> has a hierarchical scheme: the first
+    two characters indicate the general class of the condition, the
+    last three characters indicate a subclass of the general
+    condition.  A successful state is indicated by the code
+    <literal>00000</literal>.  The <literal>SQLSTATE</literal> codes are for
+    the most part defined in the SQL standard.  The
+    <productname>PostgreSQL</productname> server natively supports
+    <literal>SQLSTATE</literal> error codes; therefore a high degree
+    of consistency can be achieved by using this error code scheme
+    throughout all applications.  For further information see
+    <xref linkend="errcodes-appendix"/>.
+   </para>
+
+   <para>
+    <literal>SQLCODE</literal>, the deprecated error code scheme, is a
+    simple integer.  A value of 0 indicates success, a positive value
+    indicates success with additional information, a negative value
+    indicates an error.  The SQL standard only defines the positive
+    value +100, which indicates that the last command returned or
+    affected zero rows, and no specific negative values.  Therefore,
+    this scheme can only achieve poor portability and does not have a
+    hierarchical code assignment.  Historically, the embedded SQL
+    processor for <productname>PostgreSQL</productname> has assigned
+    some specific <literal>SQLCODE</literal> values for its use, which
+    are listed below with their numeric value and their symbolic name.
+    Remember that these are not portable to other SQL implementations.
+    To simplify the porting of applications to the
+    <literal>SQLSTATE</literal> scheme, the corresponding
+    <literal>SQLSTATE</literal> is also listed.  There is, however, no
+    one-to-one or one-to-many mapping between the two schemes (indeed
+    it is many-to-many), so you should consult the global
+    <literal>SQLSTATE</literal> listing in <xref linkend="errcodes-appendix"/>
+    in each case.
+   </para>
+
+   <para>
+    These are the assigned <literal>SQLCODE</literal> values:
+
+    <variablelist>
+     <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-no-error">
+      <term>0 (<symbol>ECPG_NO_ERROR</symbol>)</term>
+      <listitem>
+       <para>
+        Indicates no error. (SQLSTATE 00000)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-not-found">
+     <term>100 (<symbol>ECPG_NOT_FOUND</symbol>)</term>
+     <listitem>
+      <para>
+       This is a harmless condition indicating that the last command
+       retrieved or processed zero rows, or that you are at the end of
+       the cursor.  (SQLSTATE 02000)
+      </para>
+
+      <para>
+       When processing a cursor in a loop, you could use this code as
+       a way to detect when to abort the loop, like this:
+<programlisting>
+while (1)
+{
+    EXEC SQL FETCH ... ;
+    if (sqlca.sqlcode == ECPG_NOT_FOUND)
+        break;
+}
+</programlisting>
+       But <literal>WHENEVER NOT FOUND DO BREAK</literal> effectively
+       does this internally, so there is usually no advantage in
+       writing this out explicitly.
+      </para>
+     </listitem>
+    </varlistentry>
+
+     <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-out-of-memory">
+      <term>-12 (<symbol>ECPG_OUT_OF_MEMORY</symbol>)</term>
+      <listitem>
+       <para>
+        Indicates that your virtual memory is exhausted.  The numeric
+        value is defined as <literal>-ENOMEM</literal>.  (SQLSTATE
+        YE001)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-unsupported">
+     <term>-200 (<symbol>ECPG_UNSUPPORTED</symbol>)</term>
+     <listitem>
+      <para>
+       Indicates the preprocessor has generated something that the
+       library does not know about.  Perhaps you are running
+       incompatible versions of the preprocessor and the
+       library. (SQLSTATE YE002)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-too-many-arguments">
+     <term>-201 (<symbol>ECPG_TOO_MANY_ARGUMENTS</symbol>)</term>
+     <listitem>
+      <para>
+       This means that the command specified more host variables than
+       the command expected.  (SQLSTATE 07001 or 07002)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-too-few-arguments">
+     <term>-202 (<symbol>ECPG_TOO_FEW_ARGUMENTS</symbol>)</term>
+     <listitem>
+      <para>
+       This means that the command specified fewer host variables than
+       the command expected.  (SQLSTATE 07001 or 07002)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-too-many-matches">
+     <term>-203 (<symbol>ECPG_TOO_MANY_MATCHES</symbol>)</term>
+     <listitem>
+      <para>
+       This means a query has returned multiple rows but the statement
+       was only prepared to store one result row (for example, because
+       the specified variables are not arrays).  (SQLSTATE 21000)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-int-format">
+     <term>-204 (<symbol>ECPG_INT_FORMAT</symbol>)</term>
+     <listitem>
+      <para>
+       The host variable is of type <type>int</type> and the datum in
+       the database is of a different type and contains a value that
+       cannot be interpreted as an <type>int</type>.  The library uses
+       <function>strtol()</function> for this conversion.  (SQLSTATE
+       42804)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-uint-format">
+     <term>-205 (<symbol>ECPG_UINT_FORMAT</symbol>)</term>
+     <listitem>
+      <para>
+       The host variable is of type <type>unsigned int</type> and the
+       datum in the database is of a different type and contains a
+       value that cannot be interpreted as an <type>unsigned
+       int</type>.  The library uses <function>strtoul()</function>
+       for this conversion.  (SQLSTATE 42804)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-float-format">
+     <term>-206 (<symbol>ECPG_FLOAT_FORMAT</symbol>)</term>
+     <listitem>
+      <para>
+       The host variable is of type <type>float</type> and the datum
+       in the database is of another type and contains a value that
+       cannot be interpreted as a <type>float</type>.  The library
+       uses <function>strtod()</function> for this conversion.
+       (SQLSTATE 42804)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-numeric-format">
+     <term>-207 (<symbol>ECPG_NUMERIC_FORMAT</symbol>)</term>
+     <listitem>
+      <para>
+       The host variable is of type <type>numeric</type> and the datum
+       in the database is of another type and contains a value that
+       cannot be interpreted as a <type>numeric</type> value.
+       (SQLSTATE 42804)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-interval-format">
+     <term>-208 (<symbol>ECPG_INTERVAL_FORMAT</symbol>)</term>
+     <listitem>
+      <para>
+       The host variable is of type <type>interval</type> and the datum
+       in the database is of another type and contains a value that
+       cannot be interpreted as an <type>interval</type> value.
+       (SQLSTATE 42804)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-date-format">
+     <term>-209 (<symbol>ECPG_DATE_FORMAT</symbol>)</term>
+     <listitem>
+      <para>
+       The host variable is of type <type>date</type> and the datum in
+       the database is of another type and contains a value that
+       cannot be interpreted as a <type>date</type> value.
+       (SQLSTATE 42804)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-timestamp-format">
+     <term>-210 (<symbol>ECPG_TIMESTAMP_FORMAT</symbol>)</term>
+     <listitem>
+      <para>
+       The host variable is of type <type>timestamp</type> and the
+       datum in the database is of another type and contains a value
+       that cannot be interpreted as a <type>timestamp</type> value.
+       (SQLSTATE 42804)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-convert-bool">
+     <term>-211 (<symbol>ECPG_CONVERT_BOOL</symbol>)</term>
+     <listitem>
+      <para>
+       This means the host variable is of type <type>bool</type> and
+       the datum in the database is neither <literal>'t'</literal> nor
+       <literal>'f'</literal>.  (SQLSTATE 42804)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-empty">
+     <term>-212 (<symbol>ECPG_EMPTY</symbol>)</term>
+     <listitem>
+      <para>
+       The statement sent to the <productname>PostgreSQL</productname>
+       server was empty.  (This cannot normally happen in an embedded
+       SQL program, so it might point to an internal error.)  (SQLSTATE
+       YE002)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-missing-indicator">
+     <term>-213 (<symbol>ECPG_MISSING_INDICATOR</symbol>)</term>
+     <listitem>
+      <para>
+       A null value was returned and no null indicator variable was
+       supplied.  (SQLSTATE 22002)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-no-array">
+     <term>-214 (<symbol>ECPG_NO_ARRAY</symbol>)</term>
+     <listitem>
+      <para>
+       An ordinary variable was used in a place that requires an
+       array.  (SQLSTATE 42804)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-data-not-array">
+     <term>-215 (<symbol>ECPG_DATA_NOT_ARRAY</symbol>)</term>
+     <listitem>
+      <para>
+       The database returned an ordinary variable in a place that
+       requires array value.  (SQLSTATE 42804)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-array-insert">
+     <term>-216 (<symbol>ECPG_ARRAY_INSERT</symbol>)</term>
+     <listitem>
+      <para>
+       The value could not be inserted into the array.  (SQLSTATE
+       42804)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-no-conn">
+     <term>-220 (<symbol>ECPG_NO_CONN</symbol>)</term>
+     <listitem>
+      <para>
+       The program tried to access a connection that does not exist.
+       (SQLSTATE 08003)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-not-conn">
+     <term>-221 (<symbol>ECPG_NOT_CONN</symbol>)</term>
+     <listitem>
+      <para>
+       The program tried to access a connection that does exist but is
+       not open.  (This is an internal error.)  (SQLSTATE YE002)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-invalid-stmt">
+     <term>-230 (<symbol>ECPG_INVALID_STMT</symbol>)</term>
+     <listitem>
+      <para>
+       The statement you are trying to use has not been prepared.
+       (SQLSTATE 26000)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-informix-duplicate-key">
+     <term>-239 (<symbol>ECPG_INFORMIX_DUPLICATE_KEY</symbol>)</term>
+     <listitem>
+      <para>
+       Duplicate key error, violation of unique constraint (Informix
+       compatibility mode).  (SQLSTATE 23505)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-unknown-descriptor">
+     <term>-240 (<symbol>ECPG_UNKNOWN_DESCRIPTOR</symbol>)</term>
+     <listitem>
+      <para>
+       The descriptor specified was not found.  The statement you are
+       trying to use has not been prepared.  (SQLSTATE 33000)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-invalid-descriptor-index">
+     <term>-241 (<symbol>ECPG_INVALID_DESCRIPTOR_INDEX</symbol>)</term>
+     <listitem>
+      <para>
+       The descriptor index specified was out of range.  (SQLSTATE
+       07009)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-unknown-descriptor-item">
+     <term>-242 (<symbol>ECPG_UNKNOWN_DESCRIPTOR_ITEM</symbol>)</term>
+     <listitem>
+      <para>
+       An invalid descriptor item was requested.  (This is an internal
+       error.)  (SQLSTATE YE002)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-var-not-numeric">
+     <term>-243 (<symbol>ECPG_VAR_NOT_NUMERIC</symbol>)</term>
+     <listitem>
+      <para>
+       During the execution of a dynamic statement, the database
+       returned a numeric value and the host variable was not numeric.
+       (SQLSTATE 07006)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-var-not-char">
+     <term>-244 (<symbol>ECPG_VAR_NOT_CHAR</symbol>)</term>
+     <listitem>
+      <para>
+       During the execution of a dynamic statement, the database
+       returned a non-numeric value and the host variable was numeric.
+       (SQLSTATE 07006)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-informix-subselect-not-one">
+     <term>-284 (<symbol>ECPG_INFORMIX_SUBSELECT_NOT_ONE</symbol>)</term>
+     <listitem>
+      <para>
+       A result of the subquery is not single row (Informix
+       compatibility mode).  (SQLSTATE 21000)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-pgsql">
+     <term>-400 (<symbol>ECPG_PGSQL</symbol>)</term>
+     <listitem>
+      <para>
+       Some error caused by the <productname>PostgreSQL</productname>
+       server.  The message contains the error message from the
+       <productname>PostgreSQL</productname> server.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-trans">
+     <term>-401 (<symbol>ECPG_TRANS</symbol>)</term>
+     <listitem>
+      <para>
+       The <productname>PostgreSQL</productname> server signaled that
+       we cannot start, commit, or rollback the transaction.
+       (SQLSTATE 08007)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-connect">
+     <term>-402 (<symbol>ECPG_CONNECT</symbol>)</term>
+     <listitem>
+      <para>
+       The connection attempt to the database did not succeed.
+       (SQLSTATE 08001)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-duplicate-key">
+     <term>-403 (<symbol>ECPG_DUPLICATE_KEY</symbol>)</term>
+     <listitem>
+      <para>
+       Duplicate key error, violation of unique constraint.  (SQLSTATE
+       23505)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-subselect-not-one">
+     <term>-404 (<symbol>ECPG_SUBSELECT_NOT_ONE</symbol>)</term>
+     <listitem>
+      <para>
+       A result for the subquery is not single row. (SQLSTATE 21000)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <!-- currently not used by the code -->
+<!--
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-warning-unrecognized">
+     <term>-600 (<symbol>ECPG_WARNING_UNRECOGNIZED</symbol>)</term>
+     <listitem>
+      <para>
+       An unrecognized warning was received from the server.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-warning-query-ignored">
+     <term>-601 (<symbol>ECPG_WARNING_QUERY_IGNORED</symbol>)</term>
+     <listitem>
+      <para>
+       Current transaction is aborted.  Queries are ignored until the
+       end of the transaction block.
+      </para>
+     </listitem>
+    </varlistentry>
+-->
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-warning-unknown-portal">
+     <term>-602 (<symbol>ECPG_WARNING_UNKNOWN_PORTAL</symbol>)</term>
+     <listitem>
+      <para>
+       An invalid cursor name was specified. (SQLSTATE 34000)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-warning-in-transaction">
+     <term>-603 (<symbol>ECPG_WARNING_IN_TRANSACTION</symbol>)</term>
+     <listitem>
+      <para>
+       Transaction is in progress. (SQLSTATE 25001)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-warning-no-transaction">
+     <term>-604 (<symbol>ECPG_WARNING_NO_TRANSACTION</symbol>)</term>
+     <listitem>
+      <para>
+       There is no active (in-progress) transaction. (SQLSTATE 25P01)
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-sqlstate-sqlcode-ecpg-warning-portal-exists">
+     <term>-605 (<symbol>ECPG_WARNING_PORTAL_EXISTS</symbol>)</term>
+     <listitem>
+      <para>
+       An existing cursor name was specified. (SQLSTATE 42P03)
+      </para>
+     </listitem>
+    </varlistentry>
+
+   </variablelist>
+  </para>
+  </sect2>
+ </sect1>
+
+ <sect1 id="ecpg-preproc">
+  <title>Preprocessor Directives</title>
+
+  <para>
+   Several preprocessor directives are available that modify how
+   the <command>ecpg</command> preprocessor parses and processes a
+   file.
+  </para>
+
+  <sect2 id="ecpg-include">
+   <title>Including Files</title>
+
+   <para>
+    To include an external file into your embedded SQL program, use:
+<programlisting>
+EXEC SQL INCLUDE <replaceable>filename</replaceable>;
+EXEC SQL INCLUDE &lt;<replaceable>filename</replaceable>&gt;;
+EXEC SQL INCLUDE "<replaceable>filename</replaceable>";
+</programlisting>
+    The embedded SQL preprocessor will look for a file named
+    <literal><replaceable>filename</replaceable>.h</literal>,
+    preprocess it, and include it in the resulting C output.  Thus,
+    embedded SQL statements in the included file are handled correctly.
+   </para>
+
+   <para>
+    The <command>ecpg</command> preprocessor will search a file at
+    several directories in following order:
+
+    <itemizedlist>
+     <listitem><simpara>current directory</simpara></listitem>
+     <listitem><simpara><filename>/usr/local/include</filename></simpara></listitem>
+     <listitem><simpara>PostgreSQL include directory, defined at build time (e.g., <filename>/usr/local/pgsql/include</filename>)</simpara></listitem>
+     <listitem><simpara><filename>/usr/include</filename></simpara></listitem>
+    </itemizedlist>
+
+    But when <literal>EXEC SQL INCLUDE
+    "<replaceable>filename</replaceable>"</literal> is used, only the
+    current directory is searched.
+   </para>
+
+   <para>
+    In each directory, the preprocessor will first look for the file
+    name as given, and if not found will append <literal>.h</literal>
+    to the file name and try again (unless the specified file name
+    already has that suffix).
+   </para>
+
+   <para>
+    Note that <command>EXEC SQL INCLUDE</command> is <emphasis>not</emphasis> the same as:
+<programlisting>
+#include &lt;<replaceable>filename</replaceable>.h&gt;
+</programlisting>
+    because this file would not be subject to SQL command preprocessing.
+    Naturally, you can continue to use the C
+    <literal>#include</literal> directive to include other header
+    files.
+   </para>
+
+   <note>
+    <para>
+     The include file name is case-sensitive, even though the rest of
+     the <literal>EXEC SQL INCLUDE</literal> command follows the normal
+     SQL case-sensitivity rules.
+    </para>
+   </note>
+  </sect2>
+
+  <sect2 id="ecpg-define">
+   <title>The define and undef Directives</title>
+   <para>
+    Similar to the directive <literal>#define</literal> that is known from C,
+    embedded SQL has a similar concept:
+<programlisting>
+EXEC SQL DEFINE <replaceable>name</replaceable>;
+EXEC SQL DEFINE <replaceable>name</replaceable> <replaceable>value</replaceable>;
+</programlisting>
+    So you can define a name:
+<programlisting>
+EXEC SQL DEFINE HAVE_FEATURE;
+</programlisting>
+    And you can also define constants:
+<programlisting>
+EXEC SQL DEFINE MYNUMBER 12;
+EXEC SQL DEFINE MYSTRING 'abc';
+</programlisting>
+    Use <literal>undef</literal> to remove a previous definition:
+<programlisting>
+EXEC SQL UNDEF MYNUMBER;
+</programlisting>
+   </para>
+
+   <para>
+    Of course you can continue to use the C versions <literal>#define</literal>
+    and <literal>#undef</literal> in your embedded SQL program. The difference
+    is where your defined values get evaluated. If you use <literal>EXEC SQL
+    DEFINE</literal> then the <command>ecpg</command> preprocessor evaluates the defines and substitutes
+    the values. For example if you write:
+<programlisting>
+EXEC SQL DEFINE MYNUMBER 12;
+...
+EXEC SQL UPDATE Tbl SET col = MYNUMBER;
+</programlisting>
+    then <command>ecpg</command> will already do the substitution and your C compiler will never
+    see any name or identifier <literal>MYNUMBER</literal>. Note that you cannot use
+    <literal>#define</literal> for a constant that you are going to use in an
+    embedded SQL query because in this case the embedded SQL precompiler is not
+    able to see this declaration.
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-ifdef">
+   <title>ifdef, ifndef, elif, else, and endif Directives</title>
+   <para>
+   You can use the following directives to compile code sections conditionally:
+
+   <variablelist>
+    <varlistentry id="ecpg-ifdef-ifdef">
+     <term><literal>EXEC SQL ifdef <replaceable>name</replaceable>;</literal></term>
+     <listitem>
+     <para>
+      Checks a <replaceable>name</replaceable> and processes subsequent lines if
+      <replaceable>name</replaceable> has been defined via <literal>EXEC SQL define
+      <replaceable>name</replaceable></literal>.
+     </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-ifdef-ifndef">
+     <term><literal>EXEC SQL ifndef <replaceable>name</replaceable>;</literal></term>
+     <listitem>
+     <para>
+      Checks a <replaceable>name</replaceable> and processes subsequent lines if
+      <replaceable>name</replaceable> has <emphasis>not</emphasis> been defined via
+      <literal>EXEC SQL define <replaceable>name</replaceable></literal>.
+     </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-ifdef-elif">
+     <term><literal>EXEC SQL elif <replaceable>name</replaceable>;</literal></term>
+     <listitem>
+     <para>
+      Begins an optional alternative section after an
+      <literal>EXEC SQL ifdef <replaceable>name</replaceable></literal> or
+      <literal>EXEC SQL ifndef <replaceable>name</replaceable></literal>
+      directive.  Any number of <literal>elif</literal> sections can appear.
+      Lines following an <literal>elif</literal> will be processed
+      if <replaceable>name</replaceable> has been
+      defined <emphasis>and</emphasis> no previous section of the same
+      <literal>ifdef</literal>/<literal>ifndef</literal>...<literal>endif</literal>
+      construct has been processed.
+     </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-ifdef-else">
+     <term><literal>EXEC SQL else;</literal></term>
+     <listitem>
+     <para>
+      Begins an optional, final alternative section after an
+      <literal>EXEC SQL ifdef <replaceable>name</replaceable></literal> or
+      <literal>EXEC SQL ifndef <replaceable>name</replaceable></literal>
+      directive.  Subsequent lines will be processed if no previous section
+      of the same
+      <literal>ifdef</literal>/<literal>ifndef</literal>...<literal>endif</literal>
+      construct has been processed.
+     </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry id="ecpg-ifdef-endif">
+     <term><literal>EXEC SQL endif;</literal></term>
+     <listitem>
+     <para>
+      Ends an
+      <literal>ifdef</literal>/<literal>ifndef</literal>...<literal>endif</literal>
+      construct.  Subsequent lines are processed normally.
+     </para>
+     </listitem>
+    </varlistentry>
+   </variablelist>
+   </para>
+
+   <para>
+    <literal>ifdef</literal>/<literal>ifndef</literal>...<literal>endif</literal>
+    constructs can be nested, up to 127 levels deep.
+   </para>
+
+   <para>
+    This example will compile exactly one of the three <literal>SET
+    TIMEZONE</literal> commands:
+<programlisting>
+EXEC SQL ifdef TZVAR;
+EXEC SQL SET TIMEZONE TO TZVAR;
+EXEC SQL elif TZNAME;
+EXEC SQL SET TIMEZONE TO TZNAME;
+EXEC SQL else;
+EXEC SQL SET TIMEZONE TO 'GMT';
+EXEC SQL endif;
+</programlisting>
+   </para>
+
+  </sect2>
+ </sect1>
+
+  <sect1 id="ecpg-process">
+  <title>Processing Embedded SQL Programs</title>
+
+  <para>
+   Now that you have an idea how to form embedded SQL C programs, you
+   probably want to know how to compile them.  Before compiling you
+   run the file through the embedded <acronym>SQL</acronym>
+   <acronym>C</acronym> preprocessor, which converts the
+   <acronym>SQL</acronym> statements you used to special function
+   calls.  After compiling, you must link with a special library that
+   contains the needed functions. These functions fetch information
+   from the arguments, perform the <acronym>SQL</acronym> command using
+   the <application>libpq</application> interface, and put the result
+   in the arguments specified for output.
+  </para>
+
+  <para>
+   The preprocessor program is called <filename>ecpg</filename> and is
+   included in a normal <productname>PostgreSQL</productname> installation.
+   Embedded SQL programs are typically named with an extension
+   <filename>.pgc</filename>.  If you have a program file called
+   <filename>prog1.pgc</filename>, you can preprocess it by simply
+   calling:
+<programlisting>
+ecpg prog1.pgc
+</programlisting>
+   This will create a file called <filename>prog1.c</filename>.  If
+   your input files do not follow the suggested naming pattern, you
+   can specify the output file explicitly using the
+   <option>-o</option> option.
+  </para>
+
+  <para>
+   The preprocessed file can be compiled normally, for example:
+<programlisting>
+cc -c prog1.c
+</programlisting>
+   The generated C source files include header files from the
+   <productname>PostgreSQL</productname> installation, so if you installed
+   <productname>PostgreSQL</productname> in a location that is not searched by
+   default, you have to add an option such as
+   <literal>-I/usr/local/pgsql/include</literal> to the compilation
+   command line.
+  </para>
+
+  <para>
+   To link an embedded SQL program, you need to include the
+   <filename>libecpg</filename> library, like so:
+<programlisting>
+cc -o myprog prog1.o prog2.o ... -lecpg
+</programlisting>
+   Again, you might have to add an option like
+   <literal>-L/usr/local/pgsql/lib</literal> to that command line.
+  </para>
+
+  <para>
+   You can
+   use <command>pg_config</command><indexterm><primary>pg_config</primary><secondary sortas="ecpg">with
+   ecpg</secondary></indexterm>
+   or <command>pkg-config</command><indexterm><primary>pkg-config</primary><secondary sortas="ecpg">with
+   ecpg</secondary></indexterm> with package name <literal>libecpg</literal> to
+   get the paths for your installation.
+  </para>
+
+  <para>
+   If you manage the build process of a larger project using
+   <application>make</application>, it might be convenient to include
+   the following implicit rule to your makefiles:
+<programlisting>
+ECPG = ecpg
+
+%.c: %.pgc
+        $(ECPG) $&lt;
+</programlisting>
+  </para>
+
+  <para>
+   The complete syntax of the <command>ecpg</command> command is
+   detailed in <xref linkend="app-ecpg"/>.
+  </para>
+
+  <para>
+   The <application>ecpg</application> library is thread-safe by
+   default.  However, you might need to use some threading
+   command-line options to compile your client code.
+  </para>
+ </sect1>
+
+ <sect1 id="ecpg-library">
+  <title>Library Functions</title>
+
+  <para>
+   The <filename>libecpg</filename> library primarily contains
+   <quote>hidden</quote> functions that are used to implement the
+   functionality expressed by the embedded SQL commands.  But there
+   are some functions that can usefully be called directly.  Note that
+   this makes your code unportable.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <function>ECPGdebug(int <replaceable>on</replaceable>, FILE
+     *<replaceable>stream</replaceable>)</function> turns on debug
+     logging if called with the first argument non-zero. Debug logging
+     is done on <replaceable>stream</replaceable>.  The log contains
+     all <acronym>SQL</acronym> statements with all the input
+     variables inserted, and the results from the
+     <productname>PostgreSQL</productname> server. This can be very
+     useful when searching for errors in your <acronym>SQL</acronym>
+     statements.
+    </para>
+    <note>
+    <para>
+    On Windows, if the <application>ecpg</application> libraries and an application are
+    compiled with different flags, this function call will crash the
+    application because the internal representation of the
+    <literal>FILE</literal> pointers differ.  Specifically,
+    multithreaded/single-threaded, release/debug, and static/dynamic
+    flags should be the same for the library and all applications using
+    that library.
+    </para>
+    </note>
+   </listitem>
+
+   <listitem>
+     <para>
+       <function>ECPGget_PGconn(const char *<replaceable>connection_name</replaceable>)
+       </function> returns the library database connection handle identified by the given name.
+       If <replaceable>connection_name</replaceable> is set to <literal>NULL</literal>, the current
+       connection handle is returned. If no connection handle can be identified, the function returns
+       <literal>NULL</literal>. The returned connection handle can be used to call any other functions
+       from <application>libpq</application>, if necessary.
+     </para>
+     <note>
+     <para>
+       It is a bad idea to manipulate database connection handles made from <application>ecpg</application> directly
+       with <application>libpq</application> routines.
+     </para>
+     </note>
+   </listitem>
+
+   <listitem>
+     <para>
+       <function>ECPGtransactionStatus(const char *<replaceable>connection_name</replaceable>)</function>
+       returns the current transaction status of the given connection identified by <replaceable>connection_name</replaceable>.
+       See <xref linkend="libpq-status"/> and libpq's <xref linkend="libpq-PQtransactionStatus"/> for details about the returned status codes.
+     </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <function>ECPGstatus(int <replaceable>lineno</replaceable>,
+     const char* <replaceable>connection_name</replaceable>)</function>
+     returns true if you are connected to a database and false if not.
+     <replaceable>connection_name</replaceable> can be <literal>NULL</literal>
+     if a single connection is being used.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </sect1>
+
+ <sect1 id="ecpg-lo">
+  <title>Large Objects</title>
+
+  <para>
+   Large objects are not directly supported by ECPG, but ECPG
+   application can manipulate large objects through the libpq large
+   object functions, obtaining the necessary <type>PGconn</type>
+   object by calling the <function>ECPGget_PGconn()</function>
+   function.  (However, use of
+   the <function>ECPGget_PGconn()</function> function and touching
+   <type>PGconn</type> objects directly should be done very carefully
+   and ideally not mixed with other ECPG database access calls.)
+  </para>
+
+  <para>
+   For more details about the <function>ECPGget_PGconn()</function>, see
+   <xref linkend="ecpg-library"/>.  For information about the large
+   object function interface, see <xref linkend="largeobjects"/>.
+  </para>
+
+  <para>
+   Large object functions have to be called in a transaction block, so
+   when autocommit is off, <command>BEGIN</command> commands have to
+   be issued explicitly.
+  </para>
+
+  <para>
+   <xref linkend="ecpg-lo-example"/> shows an example program that
+   illustrates how to create, write, and read a large object in an
+   ECPG application.
+  </para>
+
+  <example id="ecpg-lo-example">
+   <title>ECPG Program Accessing Large Objects</title>
+<programlisting><![CDATA[
+#include <stdio.h>
+#include <stdlib.h>
+#include <libpq-fe.h>
+#include <libpq/libpq-fs.h>
+
+EXEC SQL WHENEVER SQLERROR STOP;
+
+int
+main(void)
+{
+    PGconn     *conn;
+    Oid         loid;
+    int         fd;
+    char        buf[256];
+    int         buflen = 256;
+    char        buf2[256];
+    int         rc;
+
+    memset(buf, 1, buflen);
+
+    EXEC SQL CONNECT TO testdb AS con1;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+
+    conn = ECPGget_PGconn("con1");
+    printf("conn = %p\n", conn);
+
+    /* create */
+    loid = lo_create(conn, 0);
+    if (loid &lt; 0)
+        printf("lo_create() failed: %s", PQerrorMessage(conn));
+
+    printf("loid = %d\n", loid);
+
+    /* write test */
+    fd = lo_open(conn, loid, INV_READ|INV_WRITE);
+    if (fd &lt; 0)
+        printf("lo_open() failed: %s", PQerrorMessage(conn));
+
+    printf("fd = %d\n", fd);
+
+    rc = lo_write(conn, fd, buf, buflen);
+    if (rc &lt; 0)
+        printf("lo_write() failed\n");
+
+    rc = lo_close(conn, fd);
+    if (rc &lt; 0)
+        printf("lo_close() failed: %s", PQerrorMessage(conn));
+
+    /* read test */
+    fd = lo_open(conn, loid, INV_READ);
+    if (fd &lt; 0)
+        printf("lo_open() failed: %s", PQerrorMessage(conn));
+
+    printf("fd = %d\n", fd);
+
+    rc = lo_read(conn, fd, buf2, buflen);
+    if (rc &lt; 0)
+        printf("lo_read() failed\n");
+
+    rc = lo_close(conn, fd);
+    if (rc &lt; 0)
+        printf("lo_close() failed: %s", PQerrorMessage(conn));
+
+    /* check */
+    rc = memcmp(buf, buf2, buflen);
+    printf("memcmp() = %d\n", rc);
+
+    /* cleanup */
+    rc = lo_unlink(conn, loid);
+    if (rc &lt; 0)
+        printf("lo_unlink() failed: %s", PQerrorMessage(conn));
+
+    EXEC SQL COMMIT;
+    EXEC SQL DISCONNECT ALL;
+    return 0;
+}
+]]></programlisting>
+  </example>
+ </sect1>
+
+ <sect1 id="ecpg-cpp">
+  <title><acronym>C++</acronym> Applications</title>
+
+  <para>
+   ECPG has some limited support for C++ applications.  This section
+   describes some caveats.
+  </para>
+
+  <para>
+   The <command>ecpg</command> preprocessor takes an input file
+   written in C (or something like C) and embedded SQL commands,
+   converts the embedded SQL commands into C language chunks, and
+   finally generates a <filename>.c</filename> file.  The header file
+   declarations of the library functions used by the C language chunks
+   that <command>ecpg</command> generates are wrapped
+   in <literal>extern "C" { ... }</literal> blocks when used under
+   C++, so they should work seamlessly in C++.
+  </para>
+
+  <para>
+   In general, however, the <command>ecpg</command> preprocessor only
+   understands C; it does not handle the special syntax and reserved
+   words of the C++ language.  So, some embedded SQL code written in
+   C++ application code that uses complicated features specific to C++
+   might fail to be preprocessed correctly or might not work as
+   expected.
+  </para>
+
+  <para>
+   A safe way to use the embedded SQL code in a C++ application is
+   hiding the ECPG calls in a C module, which the C++ application code
+   calls into to access the database, and linking that together with
+   the rest of the C++ code.  See <xref linkend="ecpg-cpp-and-c"/>
+   about that.
+  </para>
+
+  <sect2 id="ecpg-cpp-scope">
+   <title>Scope for Host Variables</title>
+
+   <para>
+    The <command>ecpg</command> preprocessor understands the scope of
+    variables in C.  In the C language, this is rather simple because
+    the scopes of variables is based on their code blocks.  In C++,
+    however, the class member variables are referenced in a different
+    code block from the declared position, so
+    the <command>ecpg</command> preprocessor will not understand the
+    scope of the class member variables.
+   </para>
+
+   <para>
+    For example, in the following case, the <command>ecpg</command>
+    preprocessor cannot find any declaration for the
+    variable <literal>dbname</literal> in the <literal>test</literal>
+    method, so an error will occur.
+
+<programlisting>
+class TestCpp
+{
+    EXEC SQL BEGIN DECLARE SECTION;
+    char dbname[1024];
+    EXEC SQL END DECLARE SECTION;
+
+  public:
+    TestCpp();
+    void test();
+    ~TestCpp();
+};
+
+TestCpp::TestCpp()
+{
+    EXEC SQL CONNECT TO testdb1;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+}
+
+void Test::test()
+{
+    EXEC SQL SELECT current_database() INTO :dbname;
+    printf("current_database = %s\n", dbname);
+}
+
+TestCpp::~TestCpp()
+{
+    EXEC SQL DISCONNECT ALL;
+}
+</programlisting>
+
+    This code will result in an error like this:
+<screen>
+<userinput>ecpg test_cpp.pgc</userinput>
+test_cpp.pgc:28: ERROR: variable "dbname" is not declared
+</screen>
+   </para>
+
+   <para>
+    To avoid this scope issue, the <literal>test</literal> method
+    could be modified to use a local variable as intermediate storage.
+    But this approach is only a poor workaround, because it uglifies
+    the code and reduces performance.
+
+<programlisting>
+void TestCpp::test()
+{
+    EXEC SQL BEGIN DECLARE SECTION;
+    char tmp[1024];
+    EXEC SQL END DECLARE SECTION;
+
+    EXEC SQL SELECT current_database() INTO :tmp;
+    strlcpy(dbname, tmp, sizeof(tmp));
+
+    printf("current_database = %s\n", dbname);
+}
+</programlisting>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-cpp-and-c">
+   <title>C++ Application Development with External C Module</title>
+
+   <para>
+    If you understand these technical limitations of
+    the <command>ecpg</command> preprocessor in C++, you might come to
+    the conclusion that linking C objects and C++ objects at the link
+    stage to enable C++ applications to use ECPG features could be
+    better than writing some embedded SQL commands in C++ code
+    directly.  This section describes a way to separate some embedded
+    SQL commands from C++ application code with a simple example.  In
+    this example, the application is implemented in C++, while C and
+    ECPG is used to connect to the PostgreSQL server.
+   </para>
+
+   <para>
+    Three kinds of files have to be created: a C file
+    (<filename>*.pgc</filename>), a header file, and a C++ file:
+
+    <variablelist>
+     <varlistentry id="ecpg-cpp-and-c-test-mod-pgc">
+      <term><filename>test_mod.pgc</filename></term>
+      <listitem>
+       <para>
+        A sub-routine module to execute SQL commands embedded in C.
+        It is going to be converted
+        into <filename>test_mod.c</filename> by the preprocessor.
+
+<programlisting>
+#include "test_mod.h"
+#include &lt;stdio.h&gt;
+
+void
+db_connect()
+{
+    EXEC SQL CONNECT TO testdb1;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+}
+
+void
+db_test()
+{
+    EXEC SQL BEGIN DECLARE SECTION;
+    char dbname[1024];
+    EXEC SQL END DECLARE SECTION;
+
+    EXEC SQL SELECT current_database() INTO :dbname;
+    printf("current_database = %s\n", dbname);
+}
+
+void
+db_disconnect()
+{
+    EXEC SQL DISCONNECT ALL;
+}
+</programlisting>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-cpp-and-c-test-mod-h">
+      <term><filename>test_mod.h</filename></term>
+      <listitem>
+       <para>
+        A header file with declarations of the functions in the C
+        module (<filename>test_mod.pgc</filename>).  It is included by
+        <filename>test_cpp.cpp</filename>.  This file has to have an
+        <literal>extern "C"</literal> block around the declarations,
+        because it will be linked from the C++ module.
+
+<programlisting>
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void db_connect();
+void db_test();
+void db_disconnect();
+
+#ifdef __cplusplus
+}
+#endif
+</programlisting>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-cpp-and-c-test-cpp-cpp">
+      <term><filename>test_cpp.cpp</filename></term>
+      <listitem>
+       <para>
+        The main code for the application, including
+        the <function>main</function> routine, and in this example a
+        C++ class.
+
+<programlisting>
+#include "test_mod.h"
+
+class TestCpp
+{
+  public:
+    TestCpp();
+    void test();
+    ~TestCpp();
+};
+
+TestCpp::TestCpp()
+{
+    db_connect();
+}
+
+void
+TestCpp::test()
+{
+    db_test();
+}
+
+TestCpp::~TestCpp()
+{
+    db_disconnect();
+}
+
+int
+main(void)
+{
+    TestCpp *t = new TestCpp();
+
+    t->test();
+    return 0;
+}
+</programlisting>
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+
+   <para>
+    To build the application, proceed as follows.  Convert
+    <filename>test_mod.pgc</filename> into <filename>test_mod.c</filename> by
+    running <command>ecpg</command>, and generate
+    <filename>test_mod.o</filename> by compiling
+    <filename>test_mod.c</filename> with the C compiler:
+<programlisting>
+ecpg -o test_mod.c test_mod.pgc
+cc -c test_mod.c -o test_mod.o
+</programlisting>
+   </para>
+
+   <para>
+    Next, generate <filename>test_cpp.o</filename> by compiling
+    <filename>test_cpp.cpp</filename> with the C++ compiler:
+<programlisting>
+c++ -c test_cpp.cpp -o test_cpp.o
+</programlisting>
+   </para>
+
+   <para>
+    Finally, link these object files, <filename>test_cpp.o</filename>
+    and <filename>test_mod.o</filename>, into one executable, using the C++
+    compiler driver:
+<programlisting>
+c++ test_cpp.o test_mod.o -lecpg -o test_cpp
+</programlisting>
+   </para>
+  </sect2>
+ </sect1>
+
+ <sect1 id="ecpg-sql-commands">
+  <title>Embedded SQL Commands</title>
+
+  <para>
+   This section describes all SQL commands that are specific to
+   embedded SQL.  Also refer to the SQL commands listed
+   in <xref linkend="sql-commands"/>, which can also be used in
+   embedded SQL, unless stated otherwise.
+  </para>
+
+  <refentry id="ecpg-sql-allocate-descriptor">
+   <refnamediv>
+    <refname>ALLOCATE DESCRIPTOR</refname>
+    <refpurpose>allocate an SQL descriptor area</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+ALLOCATE DESCRIPTOR <replaceable class="parameter">name</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>ALLOCATE DESCRIPTOR</command> allocates a new named SQL
+     descriptor area, which can be used to exchange data between the
+     PostgreSQL server and the host program.
+    </para>
+
+    <para>
+     Descriptor areas should be freed after use using
+     the <command>DEALLOCATE DESCRIPTOR</command> command.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-allocate-descriptor-name">
+      <term><replaceable class="parameter">name</replaceable></term>
+      <listitem>
+       <para>
+        A name of SQL descriptor, case sensitive.  This can be an SQL
+        identifier or a host variable.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+<programlisting>
+EXEC SQL ALLOCATE DESCRIPTOR mydesc;
+</programlisting>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>ALLOCATE DESCRIPTOR</command> is specified in the SQL
+     standard.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="ecpg-sql-deallocate-descriptor"/></member>
+     <member><xref linkend="ecpg-sql-get-descriptor"/></member>
+     <member><xref linkend="ecpg-sql-set-descriptor"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-connect">
+   <refnamediv>
+    <refname>CONNECT</refname>
+    <refpurpose>establish a database connection</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+CONNECT TO <replaceable>connection_target</replaceable> [ AS <replaceable>connection_name</replaceable> ] [ USER <replaceable>connection_user</replaceable> ]
+CONNECT TO DEFAULT
+CONNECT <replaceable>connection_user</replaceable>
+DATABASE <replaceable>connection_target</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     The <command>CONNECT</command> command establishes a connection
+     between the client and the PostgreSQL server.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-connect-connection-target">
+      <term><replaceable class="parameter">connection_target</replaceable></term>
+      <listitem>
+       <para>
+        <replaceable class="parameter">connection_target</replaceable>
+        specifies the target server of the connection on one of
+        several forms.
+
+        <variablelist>
+         <varlistentry id="ecpg-sql-connect-connection-target-database-name">
+          <term>[ <replaceable>database_name</replaceable> ] [ <literal>@</literal><replaceable>host</replaceable> ] [ <literal>:</literal><replaceable>port</replaceable> ]</term>
+          <listitem>
+           <para>
+            Connect over TCP/IP
+           </para>
+          </listitem>
+         </varlistentry>
+
+         <varlistentry id="ecpg-sql-connect-connection-target-unix-domain-sockets">
+          <term><literal>unix:postgresql://</literal><replaceable>host</replaceable> [ <literal>:</literal><replaceable>port</replaceable> ] <literal>/</literal> [ <replaceable>database_name</replaceable> ] [ <literal>?</literal><replaceable>connection_option</replaceable> ]</term>
+          <listitem>
+           <para>
+            Connect over Unix-domain sockets
+           </para>
+          </listitem>
+         </varlistentry>
+
+         <varlistentry id="ecpg-sql-connect-connection-target-tcp-ip">
+          <term><literal>tcp:postgresql://</literal><replaceable>host</replaceable> [ <literal>:</literal><replaceable>port</replaceable> ] <literal>/</literal> [ <replaceable>database_name</replaceable> ] [ <literal>?</literal><replaceable>connection_option</replaceable> ]</term>
+          <listitem>
+           <para>
+            Connect over TCP/IP
+           </para>
+          </listitem>
+         </varlistentry>
+
+         <varlistentry id="ecpg-sql-connect-connection-target-constant">
+          <term>SQL string constant</term>
+          <listitem>
+           <para>
+            containing a value in one of the above forms
+           </para>
+          </listitem>
+         </varlistentry>
+
+         <varlistentry id="ecpg-sql-connect-connection-target-host-variable">
+          <term>host variable</term>
+          <listitem>
+           <para>
+            host variable of type <type>char[]</type>
+            or <type>VARCHAR[]</type> containing a value in one of the
+            above forms
+           </para>
+          </listitem>
+         </varlistentry>
+        </variablelist>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-connect-connection-name">
+      <term><replaceable class="parameter">connection_name</replaceable></term>
+      <listitem>
+       <para>
+        An optional identifier for the connection, so that it can be
+        referred to in other commands.  This can be an SQL identifier
+        or a host variable.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-connect-connection-user">
+      <term><replaceable class="parameter">connection_user</replaceable></term>
+      <listitem>
+       <para>
+        The user name for the database connection.
+       </para>
+
+       <para>
+        This parameter can also specify user name and password, using one the forms
+        <literal><replaceable>user_name</replaceable>/<replaceable>password</replaceable></literal>,
+        <literal><replaceable>user_name</replaceable> IDENTIFIED BY <replaceable>password</replaceable></literal>, or
+        <literal><replaceable>user_name</replaceable> USING <replaceable>password</replaceable></literal>.
+       </para>
+
+       <para>
+        User name and password can be SQL identifiers, string
+        constants, or host variables.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-connect-default">
+      <term><literal>DEFAULT</literal></term>
+      <listitem>
+       <para>
+        Use all default connection parameters, as defined by libpq.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+    <para>
+     Here a several variants for specifying connection parameters:
+<programlisting>
+EXEC SQL CONNECT TO "connectdb" AS main;
+EXEC SQL CONNECT TO "connectdb" AS second;
+EXEC SQL CONNECT TO "unix:postgresql://200.46.204.71/connectdb" AS main USER connectuser;
+EXEC SQL CONNECT TO "unix:postgresql://localhost/connectdb" AS main USER connectuser;
+EXEC SQL CONNECT TO 'connectdb' AS main;
+EXEC SQL CONNECT TO 'unix:postgresql://localhost/connectdb' AS main USER :user;
+EXEC SQL CONNECT TO :db AS :id;
+EXEC SQL CONNECT TO :db USER connectuser USING :pw;
+EXEC SQL CONNECT TO @localhost AS main USER connectdb;
+EXEC SQL CONNECT TO REGRESSDB1 as main;
+EXEC SQL CONNECT TO AS main USER connectdb;
+EXEC SQL CONNECT TO connectdb AS :id;
+EXEC SQL CONNECT TO connectdb AS main USER connectuser/connectdb;
+EXEC SQL CONNECT TO connectdb AS main;
+EXEC SQL CONNECT TO connectdb@localhost AS main;
+EXEC SQL CONNECT TO tcp:postgresql://localhost/ USER connectdb;
+EXEC SQL CONNECT TO tcp:postgresql://localhost/connectdb USER connectuser IDENTIFIED BY connectpw;
+EXEC SQL CONNECT TO tcp:postgresql://localhost:20/connectdb USER connectuser IDENTIFIED BY connectpw;
+EXEC SQL CONNECT TO unix:postgresql://localhost/ AS main USER connectdb;
+EXEC SQL CONNECT TO unix:postgresql://localhost/connectdb AS main USER connectuser;
+EXEC SQL CONNECT TO unix:postgresql://localhost/connectdb USER connectuser IDENTIFIED BY "connectpw";
+EXEC SQL CONNECT TO unix:postgresql://localhost/connectdb USER connectuser USING "connectpw";
+EXEC SQL CONNECT TO unix:postgresql://localhost/connectdb?connect_timeout=14 USER connectuser;
+</programlisting>
+    </para>
+
+    <para>
+     Here is an example program that illustrates the use of host
+     variables to specify connection parameters:
+<programlisting>
+int
+main(void)
+{
+EXEC SQL BEGIN DECLARE SECTION;
+    char *dbname     = "testdb";    /* database name */
+    char *user       = "testuser";  /* connection user name */
+    char *connection = "tcp:postgresql://localhost:5432/testdb";
+                                    /* connection string */
+    char ver[256];                  /* buffer to store the version string */
+EXEC SQL END DECLARE SECTION;
+
+    ECPGdebug(1, stderr);
+
+    EXEC SQL CONNECT TO :dbname USER :user;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+    EXEC SQL SELECT version() INTO :ver;
+    EXEC SQL DISCONNECT;
+
+    printf("version: %s\n", ver);
+
+    EXEC SQL CONNECT TO :connection USER :user;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+    EXEC SQL SELECT version() INTO :ver;
+    EXEC SQL DISCONNECT;
+
+    printf("version: %s\n", ver);
+
+    return 0;
+}
+</programlisting>
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>CONNECT</command> is specified in the SQL standard, but
+     the format of the connection parameters is
+     implementation-specific.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="ecpg-sql-disconnect"/></member>
+     <member><xref linkend="ecpg-sql-set-connection"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-deallocate-descriptor">
+   <refnamediv>
+    <refname>DEALLOCATE DESCRIPTOR</refname>
+    <refpurpose>deallocate an SQL descriptor area</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+DEALLOCATE DESCRIPTOR <replaceable class="parameter">name</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>DEALLOCATE DESCRIPTOR</command> deallocates a named SQL
+     descriptor area.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-deallocate-descriptor-name">
+      <term><replaceable class="parameter">name</replaceable></term>
+      <listitem>
+       <para>
+        The name of the descriptor which is going to be deallocated.
+        It is case sensitive.  This can be an SQL identifier or a host
+        variable.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+<programlisting>
+EXEC SQL DEALLOCATE DESCRIPTOR mydesc;
+</programlisting>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>DEALLOCATE DESCRIPTOR</command> is specified in the SQL
+     standard.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="ecpg-sql-allocate-descriptor"/></member>
+     <member><xref linkend="ecpg-sql-get-descriptor"/></member>
+     <member><xref linkend="ecpg-sql-set-descriptor"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-declare">
+   <refnamediv>
+    <refname>DECLARE</refname>
+    <refpurpose>define a cursor</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+DECLARE <replaceable class="parameter">cursor_name</replaceable> [ BINARY ] [ ASENSITIVE | INSENSITIVE ] [ [ NO ] SCROLL ] CURSOR [ { WITH | WITHOUT } HOLD ] FOR <replaceable class="parameter">prepared_name</replaceable>
+DECLARE <replaceable class="parameter">cursor_name</replaceable> [ BINARY ] [ ASENSITIVE | INSENSITIVE ] [ [ NO ] SCROLL ] CURSOR [ { WITH | WITHOUT } HOLD ] FOR <replaceable class="parameter">query</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>DECLARE</command> declares a cursor for iterating over
+     the result set of a prepared statement.  This command has
+     slightly different semantics from the direct SQL
+     command <command>DECLARE</command>: Whereas the latter executes a
+     query and prepares the result set for retrieval, this embedded
+     SQL command merely declares a name as a <quote>loop
+     variable</quote> for iterating over the result set of a query;
+     the actual execution happens when the cursor is opened with
+     the <command>OPEN</command> command.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+    <variablelist>
+
+     <varlistentry id="ecpg-sql-declare-cursor-name">
+      <term><replaceable class="parameter">cursor_name</replaceable></term>
+      <listitem>
+       <para>
+        A cursor name, case sensitive.  This can be an SQL identifier
+        or a host variable.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-declare-prepared-name">
+      <term><replaceable class="parameter">prepared_name</replaceable></term>
+      <listitem>
+       <para>
+        The name of a prepared query, either as an SQL identifier or a
+        host variable.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-declare-query">
+      <term><replaceable class="parameter">query</replaceable></term>
+      <listitem>
+       <para>
+        A <xref linkend="sql-select"/> or
+        <xref linkend="sql-values"/> command which will provide the
+        rows to be returned by the cursor.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+
+    <para>
+     For the meaning of the cursor options,
+     see <xref linkend="sql-declare"/>.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+    <para>
+     Examples declaring a cursor for a query:
+<programlisting>
+EXEC SQL DECLARE C CURSOR FOR SELECT * FROM My_Table;
+EXEC SQL DECLARE C CURSOR FOR SELECT Item1 FROM T;
+EXEC SQL DECLARE cur1 CURSOR FOR SELECT version();
+</programlisting>
+    </para>
+
+    <para>
+     An example declaring a cursor for a prepared statement:
+<programlisting>
+EXEC SQL PREPARE stmt1 AS SELECT version();
+EXEC SQL DECLARE cur1 CURSOR FOR stmt1;
+</programlisting>
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>DECLARE</command> is specified in the SQL standard.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="ecpg-sql-open"/></member>
+     <member><xref linkend="sql-close"/></member>
+     <member><xref linkend="sql-declare"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-declare-statement">
+   <refnamediv>
+    <refname>DECLARE STATEMENT</refname>
+    <refpurpose>declare SQL statement identifier</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+EXEC SQL [ AT <replaceable class="parameter">connection_name</replaceable> ] DECLARE <replaceable class="parameter">statement_name</replaceable> STATEMENT
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>DECLARE STATEMENT</command> declares an SQL statement identifier.
+     SQL statement identifier can be associated with the connection.
+     When the identifier is used by dynamic SQL statements, the statements
+     are executed using the associated connection.
+     The namespace of the declaration is the precompile unit, and multiple
+     declarations to the same SQL statement identifier are not allowed.
+     Note that if the precompiler runs in Informix compatibility mode and
+     some SQL statement is declared, "database" can not be used as a cursor
+     name.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-declare-statement-connection-name">
+      <term><replaceable class="parameter">connection_name</replaceable></term>
+      <listitem>
+       <para>
+        A database connection name established by the <command>CONNECT</command> command.
+       </para>
+       <para>
+        AT clause can be omitted, but such statement has no meaning.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-declare-statement-statement-name">
+      <term><replaceable class="parameter">statement_name</replaceable></term>
+      <listitem>
+       <para>
+        The name of an SQL statement identifier, either as an SQL identifier or a host variable.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Notes</title>
+    <para>
+     This association is valid only if the declaration is physically placed on top of a dynamic statement.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+<programlisting>
+EXEC SQL CONNECT TO postgres AS con1;
+EXEC SQL AT con1 DECLARE sql_stmt STATEMENT;
+EXEC SQL DECLARE cursor_name CURSOR FOR sql_stmt;
+EXEC SQL PREPARE sql_stmt FROM :dyn_string;
+EXEC SQL OPEN cursor_name;
+EXEC SQL FETCH cursor_name INTO :column1;
+EXEC SQL CLOSE cursor_name;
+</programlisting>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>DECLARE STATEMENT</command> is an extension of the SQL standard,
+     but can be used in famous DBMSs.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="ecpg-sql-connect"/></member>
+     <member><xref linkend="ecpg-sql-declare"/></member>
+     <member><xref linkend="ecpg-sql-open"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-describe">
+   <refnamediv>
+    <refname>DESCRIBE</refname>
+    <refpurpose>obtain information about a prepared statement or result set</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+DESCRIBE [ OUTPUT ] <replaceable class="parameter">prepared_name</replaceable> USING [ SQL ] DESCRIPTOR <replaceable class="parameter">descriptor_name</replaceable>
+DESCRIBE [ OUTPUT ] <replaceable class="parameter">prepared_name</replaceable> INTO [ SQL ] DESCRIPTOR <replaceable class="parameter">descriptor_name</replaceable>
+DESCRIBE [ OUTPUT ] <replaceable class="parameter">prepared_name</replaceable> INTO <replaceable class="parameter">sqlda_name</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>DESCRIBE</command> retrieves metadata information about
+     the result columns contained in a prepared statement, without
+     actually fetching a row.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-describe-prepared-name">
+      <term><replaceable class="parameter">prepared_name</replaceable></term>
+      <listitem>
+       <para>
+        The name of a prepared statement.  This can be an SQL
+        identifier or a host variable.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-describe-descriptor-name">
+      <term><replaceable class="parameter">descriptor_name</replaceable></term>
+      <listitem>
+       <para>
+        A descriptor name. It is case sensitive.  It can be an SQL
+        identifier or a host variable.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-describe-sqlda-name">
+      <term><replaceable class="parameter">sqlda_name</replaceable></term>
+      <listitem>
+       <para>
+        The name of an SQLDA variable.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+<programlisting>
+EXEC SQL ALLOCATE DESCRIPTOR mydesc;
+EXEC SQL PREPARE stmt1 FROM :sql_stmt;
+EXEC SQL DESCRIBE stmt1 INTO SQL DESCRIPTOR mydesc;
+EXEC SQL GET DESCRIPTOR mydesc VALUE 1 :charvar = NAME;
+EXEC SQL DEALLOCATE DESCRIPTOR mydesc;
+</programlisting>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>DESCRIBE</command> is specified in the SQL standard.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="ecpg-sql-allocate-descriptor"/></member>
+     <member><xref linkend="ecpg-sql-get-descriptor"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-disconnect">
+   <refnamediv>
+    <refname>DISCONNECT</refname>
+    <refpurpose>terminate a database connection</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+DISCONNECT <replaceable class="parameter">connection_name</replaceable>
+DISCONNECT [ CURRENT ]
+DISCONNECT ALL
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>DISCONNECT</command> closes a connection (or all
+     connections) to the database.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-disconnect-connection-name">
+      <term><replaceable class="parameter">connection_name</replaceable></term>
+      <listitem>
+       <para>
+        A database connection name established by
+        the <command>CONNECT</command> command.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-disconnect-current">
+      <term><literal>CURRENT</literal></term>
+      <listitem>
+       <para>
+        Close the <quote>current</quote> connection, which is either
+        the most recently opened connection, or the connection set by
+        the <command>SET CONNECTION</command> command.  This is also
+        the default if no argument is given to
+        the <command>DISCONNECT</command> command.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-disconnect-all">
+      <term><literal>ALL</literal></term>
+      <listitem>
+       <para>
+        Close all open connections.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+<programlisting>
+int
+main(void)
+{
+    EXEC SQL CONNECT TO testdb AS con1 USER testuser;
+    EXEC SQL CONNECT TO testdb AS con2 USER testuser;
+    EXEC SQL CONNECT TO testdb AS con3 USER testuser;
+
+    EXEC SQL DISCONNECT CURRENT;  /* close con3          */
+    EXEC SQL DISCONNECT ALL;      /* close con2 and con1 */
+
+    return 0;
+}
+</programlisting>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>DISCONNECT</command> is specified in the SQL standard.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="ecpg-sql-connect"/></member>
+     <member><xref linkend="ecpg-sql-set-connection"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-execute-immediate">
+   <refnamediv>
+    <refname>EXECUTE IMMEDIATE</refname>
+    <refpurpose>dynamically prepare and execute a statement</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+EXECUTE IMMEDIATE <replaceable class="parameter">string</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>EXECUTE IMMEDIATE</command> immediately prepares and
+     executes a dynamically specified SQL statement, without
+     retrieving result rows.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-execute-immediate-string">
+      <term><replaceable class="parameter">string</replaceable></term>
+      <listitem>
+       <para>
+        A literal string or a host variable containing the SQL
+        statement to be executed.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Notes</title>
+
+    <para>
+     In typical usage, the <replaceable>string</replaceable> is a host
+     variable reference to a string containing a dynamically-constructed
+     SQL statement.  The case of a literal string is not very useful;
+     you might as well just write the SQL statement directly, without
+     the extra typing of <command>EXECUTE IMMEDIATE</command>.
+    </para>
+
+    <para>
+     If you do use a literal string, keep in mind that any double quotes
+     you might wish to include in the SQL statement must be written as
+     octal escapes (<literal>\042</literal>) not the usual C
+     idiom <literal>\"</literal>.  This is because the string is inside
+     an <literal>EXEC SQL</literal> section, so the ECPG lexer parses it
+     according to SQL rules not C rules.  Any embedded backslashes will
+     later be handled according to C rules; but <literal>\"</literal>
+     causes an immediate syntax error because it is seen as ending the
+     literal.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+    <para>
+     Here is an example that executes an <command>INSERT</command>
+     statement using <command>EXECUTE IMMEDIATE</command> and a host
+     variable named <varname>command</varname>:
+<programlisting>
+sprintf(command, "INSERT INTO test (name, amount, letter) VALUES ('db: ''r1''', 1, 'f')");
+EXEC SQL EXECUTE IMMEDIATE :command;
+</programlisting>
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>EXECUTE IMMEDIATE</command> is specified in the SQL standard.
+    </para>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-get-descriptor">
+   <refnamediv>
+    <refname>GET DESCRIPTOR</refname>
+    <refpurpose>get information from an SQL descriptor area</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+GET DESCRIPTOR <replaceable class="parameter">descriptor_name</replaceable> <replaceable class="parameter">:cvariable</replaceable> = <replaceable class="parameter">descriptor_header_item</replaceable> [, ... ]
+GET DESCRIPTOR <replaceable class="parameter">descriptor_name</replaceable> VALUE <replaceable class="parameter">column_number</replaceable> <replaceable class="parameter">:cvariable</replaceable> = <replaceable class="parameter">descriptor_item</replaceable> [, ... ]
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>GET DESCRIPTOR</command> retrieves information about a
+     query result set from an SQL descriptor area and stores it into
+     host variables.  A descriptor area is typically populated
+     using <command>FETCH</command> or <command>SELECT</command>
+     before using this command to transfer the information into host
+     language variables.
+    </para>
+
+    <para>
+     This command has two forms: The first form retrieves
+     descriptor <quote>header</quote> items, which apply to the result
+     set in its entirety.  One example is the row count.  The second
+     form, which requires the column number as additional parameter,
+     retrieves information about a particular column.  Examples are
+     the column name and the actual column value.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-get-descriptor-descriptor-name">
+      <term><replaceable class="parameter">descriptor_name</replaceable></term>
+      <listitem>
+       <para>
+        A descriptor name.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-get-descriptor-descriptor-header-item">
+      <term><replaceable class="parameter">descriptor_header_item</replaceable></term>
+      <listitem>
+       <para>
+        A token identifying which header information item to retrieve.
+        Only <literal>COUNT</literal>, to get the number of columns in the
+        result set, is currently supported.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-get-descriptor-column-number">
+      <term><replaceable class="parameter">column_number</replaceable></term>
+      <listitem>
+       <para>
+        The number of the column about which information is to be
+        retrieved.  The count starts at 1.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-get-descriptor-descriptor-item">
+      <term><replaceable class="parameter">descriptor_item</replaceable></term>
+      <listitem>
+       <para>
+        A token identifying which item of information about a column
+        to retrieve.  See <xref linkend="ecpg-named-descriptors"/> for
+        a list of supported items.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-get-descriptor-cvariable">
+      <term><replaceable class="parameter">cvariable</replaceable></term>
+      <listitem>
+       <para>
+        A host variable that will receive the data retrieved from the
+        descriptor area.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+    <para>
+     An example to retrieve the number of columns in a result set:
+<programlisting>
+EXEC SQL GET DESCRIPTOR d :d_count = COUNT;
+</programlisting>
+    </para>
+
+    <para>
+     An example to retrieve a data length in the first column:
+<programlisting>
+EXEC SQL GET DESCRIPTOR d VALUE 1 :d_returned_octet_length = RETURNED_OCTET_LENGTH;
+</programlisting>
+    </para>
+
+    <para>
+     An example to retrieve the data body of the second column as a
+     string:
+<programlisting>
+EXEC SQL GET DESCRIPTOR d VALUE 2 :d_data = DATA;
+</programlisting>
+    </para>
+
+    <para>
+     Here is an example for a whole procedure of
+     executing <literal>SELECT current_database();</literal> and showing the number of
+     columns, the column data length, and the column data:
+<programlisting>
+int
+main(void)
+{
+EXEC SQL BEGIN DECLARE SECTION;
+    int  d_count;
+    char d_data[1024];
+    int  d_returned_octet_length;
+EXEC SQL END DECLARE SECTION;
+
+    EXEC SQL CONNECT TO testdb AS con1 USER testuser;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+    EXEC SQL ALLOCATE DESCRIPTOR d;
+
+    /* Declare, open a cursor, and assign a descriptor to the cursor  */
+    EXEC SQL DECLARE cur CURSOR FOR SELECT current_database();
+    EXEC SQL OPEN cur;
+    EXEC SQL FETCH NEXT FROM cur INTO SQL DESCRIPTOR d;
+
+    /* Get a number of total columns */
+    EXEC SQL GET DESCRIPTOR d :d_count = COUNT;
+    printf("d_count                 = %d\n", d_count);
+
+    /* Get length of a returned column */
+    EXEC SQL GET DESCRIPTOR d VALUE 1 :d_returned_octet_length = RETURNED_OCTET_LENGTH;
+    printf("d_returned_octet_length = %d\n", d_returned_octet_length);
+
+    /* Fetch the returned column as a string */
+    EXEC SQL GET DESCRIPTOR d VALUE 1 :d_data = DATA;
+    printf("d_data                  = %s\n", d_data);
+
+    /* Closing */
+    EXEC SQL CLOSE cur;
+    EXEC SQL COMMIT;
+
+    EXEC SQL DEALLOCATE DESCRIPTOR d;
+    EXEC SQL DISCONNECT ALL;
+
+    return 0;
+}
+</programlisting>
+     When the example is executed, the result will look like this:
+<screen>
+d_count                 = 1
+d_returned_octet_length = 6
+d_data                  = testdb
+</screen>
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>GET DESCRIPTOR</command> is specified in the SQL standard.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="ecpg-sql-allocate-descriptor"/></member>
+     <member><xref linkend="ecpg-sql-set-descriptor"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-open">
+   <refnamediv>
+    <refname>OPEN</refname>
+    <refpurpose>open a dynamic cursor</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+OPEN <replaceable class="parameter">cursor_name</replaceable>
+OPEN <replaceable class="parameter">cursor_name</replaceable> USING <replaceable class="parameter">value</replaceable> [, ... ]
+OPEN <replaceable class="parameter">cursor_name</replaceable> USING SQL DESCRIPTOR <replaceable class="parameter">descriptor_name</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>OPEN</command> opens a cursor and optionally binds
+     actual values to the placeholders in the cursor's declaration.
+     The cursor must previously have been declared with
+     the <command>DECLARE</command> command.  The execution
+     of <command>OPEN</command> causes the query to start executing on
+     the server.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-open-cursor-name">
+      <term><replaceable class="parameter">cursor_name</replaceable></term>
+      <listitem>
+       <para>
+        The name of the cursor to be opened.  This can be an SQL
+        identifier or a host variable.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-open-value">
+      <term><replaceable class="parameter">value</replaceable></term>
+      <listitem>
+       <para>
+        A value to be bound to a placeholder in the cursor.  This can
+        be an SQL constant, a host variable, or a host variable with
+        indicator.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-open-descriptor-name">
+      <term><replaceable class="parameter">descriptor_name</replaceable></term>
+      <listitem>
+       <para>
+        The name of a descriptor containing values to be bound to the
+        placeholders in the cursor.  This can be an SQL identifier or
+        a host variable.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+<programlisting>
+EXEC SQL OPEN a;
+EXEC SQL OPEN d USING 1, 'test';
+EXEC SQL OPEN c1 USING SQL DESCRIPTOR mydesc;
+EXEC SQL OPEN :curname1;
+</programlisting>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>OPEN</command> is specified in the SQL standard.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="ecpg-sql-declare"/></member>
+     <member><xref linkend="sql-close"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-prepare">
+   <refnamediv>
+    <refname>PREPARE</refname>
+    <refpurpose>prepare a statement for execution</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+PREPARE <replaceable class="parameter">prepared_name</replaceable> FROM <replaceable class="parameter">string</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>PREPARE</command> prepares a statement dynamically
+     specified as a string for execution.  This is different from the
+     direct SQL statement <xref linkend="sql-prepare"/>, which can also
+     be used in embedded programs.  The <xref linkend="sql-execute"/>
+     command is used to execute either kind of prepared statement.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-prepare-prepared-name">
+      <term><replaceable class="parameter">prepared_name</replaceable></term>
+      <listitem>
+       <para>
+        An identifier for the prepared query.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-prepare-string">
+      <term><replaceable class="parameter">string</replaceable></term>
+      <listitem>
+       <para>
+        A literal string or a host variable containing a preparable
+        SQL statement, one of SELECT, INSERT, UPDATE, or DELETE.
+        Use question marks (<literal>?</literal>) for parameter values
+        to be supplied at execution.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Notes</title>
+
+    <para>
+     In typical usage, the <replaceable>string</replaceable> is a host
+     variable reference to a string containing a dynamically-constructed
+     SQL statement.  The case of a literal string is not very useful;
+     you might as well just write a direct SQL <command>PREPARE</command>
+     statement.
+    </para>
+
+    <para>
+     If you do use a literal string, keep in mind that any double quotes
+     you might wish to include in the SQL statement must be written as
+     octal escapes (<literal>\042</literal>) not the usual C
+     idiom <literal>\"</literal>.  This is because the string is inside
+     an <literal>EXEC SQL</literal> section, so the ECPG lexer parses it
+     according to SQL rules not C rules.  Any embedded backslashes will
+     later be handled according to C rules; but <literal>\"</literal>
+     causes an immediate syntax error because it is seen as ending the
+     literal.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+<programlisting>
+char *stmt = "SELECT * FROM test1 WHERE a = ? AND b = ?";
+
+EXEC SQL ALLOCATE DESCRIPTOR outdesc;
+EXEC SQL PREPARE foo FROM :stmt;
+
+EXEC SQL EXECUTE foo USING SQL DESCRIPTOR indesc INTO SQL DESCRIPTOR outdesc;
+</programlisting>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>PREPARE</command> is specified in the SQL standard.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="sql-execute"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-set-autocommit">
+   <refnamediv>
+    <refname>SET AUTOCOMMIT</refname>
+    <refpurpose>set the autocommit behavior of the current session</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+SET AUTOCOMMIT { = | TO } { ON | OFF }
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>SET AUTOCOMMIT</command> sets the autocommit behavior of
+     the current database session.  By default, embedded SQL programs
+     are <emphasis>not</emphasis> in autocommit mode,
+     so <command>COMMIT</command> needs to be issued explicitly when
+     desired.  This command can change the session to autocommit mode,
+     where each individual statement is committed implicitly.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>SET AUTOCOMMIT</command> is an extension of PostgreSQL ECPG.
+    </para>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-set-connection">
+   <refnamediv>
+    <refname>SET CONNECTION</refname>
+    <refpurpose>select a database connection</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+SET CONNECTION [ TO | = ] <replaceable class="parameter">connection_name</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>SET CONNECTION</command> sets the <quote>current</quote>
+     database connection, which is the one that all commands use
+     unless overridden.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-set-connection-connection-name">
+      <term><replaceable class="parameter">connection_name</replaceable></term>
+      <listitem>
+       <para>
+        A database connection name established by
+        the <command>CONNECT</command> command.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-set-connection-current">
+      <term><literal>CURRENT</literal></term>
+      <listitem>
+       <para>
+        Set the connection to the current connection (thus, nothing happens).
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+<programlisting>
+EXEC SQL SET CONNECTION TO con2;
+EXEC SQL SET CONNECTION = con1;
+</programlisting>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>SET CONNECTION</command> is specified in the SQL standard.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="ecpg-sql-connect"/></member>
+     <member><xref linkend="ecpg-sql-disconnect"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-set-descriptor">
+   <refnamediv>
+    <refname>SET DESCRIPTOR</refname>
+    <refpurpose>set information in an SQL descriptor area</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+SET DESCRIPTOR <replaceable class="parameter">descriptor_name</replaceable> <replaceable class="parameter">descriptor_header_item</replaceable> = <replaceable>value</replaceable> [, ... ]
+SET DESCRIPTOR <replaceable class="parameter">descriptor_name</replaceable> VALUE <replaceable class="parameter">number</replaceable> <replaceable class="parameter">descriptor_item</replaceable> = <replaceable>value</replaceable> [, ...]
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     <command>SET DESCRIPTOR</command> populates an SQL descriptor
+     area with values.  The descriptor area is then typically used to
+     bind parameters in a prepared query execution.
+    </para>
+
+    <para>
+     This command has two forms: The first form applies to the
+     descriptor <quote>header</quote>, which is independent of a
+     particular datum.  The second form assigns values to particular
+     datums, identified by number.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-set-descriptor-descriptor-name">
+      <term><replaceable class="parameter">descriptor_name</replaceable></term>
+      <listitem>
+       <para>
+        A descriptor name.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-set-descriptor-descriptor-header-item">
+      <term><replaceable class="parameter">descriptor_header_item</replaceable></term>
+      <listitem>
+       <para>
+        A token identifying which header information item to set.
+        Only <literal>COUNT</literal>, to set the number of descriptor
+        items, is currently supported.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-set-descriptor-number">
+      <term><replaceable class="parameter">number</replaceable></term>
+      <listitem>
+       <para>
+        The number of the descriptor item to set.  The count starts at
+        1.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-set-descriptor-descriptor-item">
+      <term><replaceable class="parameter">descriptor_item</replaceable></term>
+      <listitem>
+       <para>
+        A token identifying which item of information to set in the
+        descriptor.  See <xref linkend="ecpg-named-descriptors"/> for a
+        list of supported items.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-set-descriptor-value">
+      <term><replaceable class="parameter">value</replaceable></term>
+      <listitem>
+       <para>
+        A value to store into the descriptor item.  This can be an SQL
+        constant or a host variable.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+<programlisting>
+EXEC SQL SET DESCRIPTOR indesc COUNT = 1;
+EXEC SQL SET DESCRIPTOR indesc VALUE 1 DATA = 2;
+EXEC SQL SET DESCRIPTOR indesc VALUE 1 DATA = :val1;
+EXEC SQL SET DESCRIPTOR indesc VALUE 2 INDICATOR = :val1, DATA = 'some string';
+EXEC SQL SET DESCRIPTOR indesc VALUE 2 INDICATOR = :val2null, DATA = :val2;
+</programlisting>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>SET DESCRIPTOR</command> is specified in the SQL standard.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>See Also</title>
+
+    <simplelist type="inline">
+     <member><xref linkend="ecpg-sql-allocate-descriptor"/></member>
+     <member><xref linkend="ecpg-sql-get-descriptor"/></member>
+    </simplelist>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-type">
+   <refnamediv>
+    <refname>TYPE</refname>
+    <refpurpose>define a new data type</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+TYPE <replaceable class="parameter">type_name</replaceable> IS <replaceable class="parameter">ctype</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     The <command>TYPE</command> command defines a new C type.  It is
+     equivalent to putting a <literal>typedef</literal> into a declare
+     section.
+    </para>
+
+    <para>
+     This command is only recognized when <command>ecpg</command> is
+     run with the <option>-c</option> option.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-type-type-name">
+      <term><replaceable class="parameter">type_name</replaceable></term>
+      <listitem>
+       <para>
+        The name for the new type.  It must be a valid C type name.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-type-ctype">
+      <term><replaceable class="parameter">ctype</replaceable></term>
+      <listitem>
+       <para>
+        A C type specification.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+<programlisting>
+EXEC SQL TYPE customer IS
+    struct
+    {
+        varchar name[50];
+        int     phone;
+    };
+
+EXEC SQL TYPE cust_ind IS
+    struct ind
+    {
+        short   name_ind;
+        short   phone_ind;
+    };
+
+EXEC SQL TYPE c IS char reference;
+EXEC SQL TYPE ind IS union { int integer; short smallint; };
+EXEC SQL TYPE intarray IS int[AMOUNT];
+EXEC SQL TYPE str IS varchar[BUFFERSIZ];
+EXEC SQL TYPE string IS char[11];
+</programlisting>
+
+    <para>
+     Here is an example program that uses <command>EXEC SQL
+     TYPE</command>:
+<programlisting>
+EXEC SQL WHENEVER SQLERROR SQLPRINT;
+
+EXEC SQL TYPE tt IS
+    struct
+    {
+        varchar v[256];
+        int     i;
+    };
+
+EXEC SQL TYPE tt_ind IS
+    struct ind {
+        short   v_ind;
+        short   i_ind;
+    };
+
+int
+main(void)
+{
+EXEC SQL BEGIN DECLARE SECTION;
+    tt t;
+    tt_ind t_ind;
+EXEC SQL END DECLARE SECTION;
+
+    EXEC SQL CONNECT TO testdb AS con1;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+
+    EXEC SQL SELECT current_database(), 256 INTO :t:t_ind LIMIT 1;
+
+    printf("t.v = %s\n", t.v.arr);
+    printf("t.i = %d\n", t.i);
+
+    printf("t_ind.v_ind = %d\n", t_ind.v_ind);
+    printf("t_ind.i_ind = %d\n", t_ind.i_ind);
+
+    EXEC SQL DISCONNECT con1;
+
+    return 0;
+}
+</programlisting>
+
+     The output from this program looks like this:
+<screen>
+t.v = testdb
+t.i = 256
+t_ind.v_ind = 0
+t_ind.i_ind = 0
+</screen>
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     The <command>TYPE</command> command is a PostgreSQL extension.
+    </para>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-var">
+   <refnamediv>
+    <refname>VAR</refname>
+    <refpurpose>define a variable</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+VAR <replaceable>varname</replaceable> IS <replaceable>ctype</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     The <command>VAR</command> command assigns a new C data type
+     to a host variable.  The host variable must be previously
+     declared in a declare section.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <variablelist>
+     <varlistentry id="ecpg-sql-var-varname">
+      <term><replaceable class="parameter">varname</replaceable></term>
+      <listitem>
+       <para>
+        A C variable name.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-sql-var-ctype">
+      <term><replaceable class="parameter">ctype</replaceable></term>
+      <listitem>
+       <para>
+        A C type specification.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+<programlisting>
+Exec sql begin declare section;
+short a;
+exec sql end declare section;
+EXEC SQL VAR a IS int;
+</programlisting>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     The <command>VAR</command> command is a PostgreSQL extension.
+    </para>
+   </refsect1>
+  </refentry>
+
+  <refentry id="ecpg-sql-whenever">
+   <refnamediv>
+    <refname>WHENEVER</refname>
+    <refpurpose>specify the action to be taken when an SQL statement causes a specific class condition to be raised</refpurpose>
+   </refnamediv>
+
+   <refsynopsisdiv>
+<synopsis>
+WHENEVER { NOT FOUND | SQLERROR | SQLWARNING } <replaceable class="parameter">action</replaceable>
+</synopsis>
+   </refsynopsisdiv>
+
+   <refsect1>
+    <title>Description</title>
+
+    <para>
+     Define a behavior which is called on the special cases (Rows not
+     found, SQL warnings or errors) in the result of SQL execution.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Parameters</title>
+
+    <para>
+     See <xref linkend="ecpg-whenever"/> for a description of the
+     parameters.
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Examples</title>
+
+<programlisting>
+EXEC SQL WHENEVER NOT FOUND CONTINUE;
+EXEC SQL WHENEVER NOT FOUND DO BREAK;
+EXEC SQL WHENEVER NOT FOUND DO CONTINUE;
+EXEC SQL WHENEVER SQLWARNING SQLPRINT;
+EXEC SQL WHENEVER SQLWARNING DO warn();
+EXEC SQL WHENEVER SQLERROR sqlprint;
+EXEC SQL WHENEVER SQLERROR CALL print2();
+EXEC SQL WHENEVER SQLERROR DO handle_error("select");
+EXEC SQL WHENEVER SQLERROR DO sqlnotice(NULL, NONO);
+EXEC SQL WHENEVER SQLERROR DO sqlprint();
+EXEC SQL WHENEVER SQLERROR GOTO error_label;
+EXEC SQL WHENEVER SQLERROR STOP;
+</programlisting>
+
+    <para>
+     A typical application is the use of <literal>WHENEVER NOT FOUND
+     BREAK</literal> to handle looping through result sets:
+<programlisting>
+int
+main(void)
+{
+    EXEC SQL CONNECT TO testdb AS con1;
+    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;
+    EXEC SQL ALLOCATE DESCRIPTOR d;
+    EXEC SQL DECLARE cur CURSOR FOR SELECT current_database(), 'hoge', 256;
+    EXEC SQL OPEN cur;
+
+    /* when end of result set reached, break out of while loop */
+    EXEC SQL WHENEVER NOT FOUND DO BREAK;
+
+    while (1)
+    {
+        EXEC SQL FETCH NEXT FROM cur INTO SQL DESCRIPTOR d;
+        ...
+    }
+
+    EXEC SQL CLOSE cur;
+    EXEC SQL COMMIT;
+
+    EXEC SQL DEALLOCATE DESCRIPTOR d;
+    EXEC SQL DISCONNECT ALL;
+
+    return 0;
+}
+</programlisting>
+    </para>
+   </refsect1>
+
+   <refsect1>
+    <title>Compatibility</title>
+
+    <para>
+     <command>WHENEVER</command> is specified in the SQL standard, but
+     most of the actions are PostgreSQL extensions.
+    </para>
+   </refsect1>
+  </refentry>
+ </sect1>
+
+ <sect1 id="ecpg-informix-compat">
+  <title><productname>Informix</productname> Compatibility Mode</title>
+  <para>
+   <command>ecpg</command> can be run in a so-called <firstterm>Informix compatibility mode</firstterm>. If
+   this mode is active, it tries to behave as if it were the <productname>Informix</productname>
+   precompiler for <productname>Informix</productname> E/SQL. Generally spoken this will allow you to use
+   the dollar sign instead of the <literal>EXEC SQL</literal> primitive to introduce
+   embedded SQL commands:
+<programlisting>
+$int j = 3;
+$CONNECT TO :dbname;
+$CREATE TABLE test(i INT PRIMARY KEY, j INT);
+$INSERT INTO test(i, j) VALUES (7, :j);
+$COMMIT;
+</programlisting>
+  </para>
+
+  <note>
+   <para>
+    There must not be any white space between the <literal>$</literal>
+    and a following preprocessor directive, that is,
+    <literal>include</literal>, <literal>define</literal>, <literal>ifdef</literal>,
+    etc.  Otherwise, the preprocessor will parse the token as a host
+    variable.
+   </para>
+  </note>
+
+  <para>
+   There are two compatibility modes: <literal>INFORMIX</literal>, <literal>INFORMIX_SE</literal>
+  </para>
+  <para>
+   When linking programs that use this compatibility mode, remember to link
+   against <literal>libcompat</literal> that is shipped with ECPG.
+  </para>
+  <para>
+   Besides the previously explained syntactic sugar, the <productname>Informix</productname> compatibility
+   mode ports some functions for input, output and transformation of data as
+   well as embedded SQL statements known from E/SQL to ECPG.
+  </para>
+  <para>
+   <productname>Informix</productname> compatibility mode is closely connected to the pgtypeslib library
+   of ECPG. pgtypeslib maps SQL data types to data types within the C host
+   program and most of the additional functions of the <productname>Informix</productname> compatibility
+   mode allow you to operate on those C host program types. Note however that
+   the extent of the compatibility is limited. It does not try to copy <productname>Informix</productname>
+   behavior; it allows you to do more or less the same operations and gives
+   you functions that have the same name and the same basic behavior but it is
+   no drop-in replacement if you are using <productname>Informix</productname> at the moment. Moreover,
+   some of the data types are different. For example,
+   <productname>PostgreSQL</productname>'s datetime and interval types do not
+   know about ranges like for example <literal>YEAR TO MINUTE</literal> so you won't
+   find support in ECPG for that either.
+  </para>
+
+  <sect2 id="ecpg-informix-types">
+   <title>Additional Types</title>
+   <para>
+    The Informix-special "string" pseudo-type for storing right-trimmed character string data is now
+    supported in Informix-mode without using <literal>typedef</literal>. In fact, in Informix-mode,
+    ECPG refuses to process source files that contain <literal>typedef sometype string;</literal>
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+string userid; /* this variable will contain trimmed data */
+EXEC SQL END DECLARE SECTION;
+
+EXEC SQL FETCH MYCUR INTO :userid;
+</programlisting>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-informix-statements">
+   <title>Additional/Missing Embedded SQL Statements</title>
+   <para>
+    <variablelist>
+     <varlistentry id="ecpg-informix-statements-close-database">
+      <term><literal>CLOSE DATABASE</literal></term>
+      <listitem>
+       <para>
+        This statement closes the current connection. In fact, this is a
+        synonym for ECPG's <literal>DISCONNECT CURRENT</literal>:
+<programlisting>
+$CLOSE DATABASE;                /* close the current connection */
+EXEC SQL CLOSE DATABASE;
+</programlisting>
+       </para>
+      </listitem>
+     </varlistentry>
+     <varlistentry id="ecpg-informix-statements-free-cursor-name">
+      <term><literal>FREE cursor_name</literal></term>
+      <listitem>
+       <para>
+        Due to differences in how ECPG works compared to Informix's ESQL/C (namely, which steps
+        are purely grammar transformations and which steps rely on the underlying run-time library)
+        there is no <literal>FREE cursor_name</literal> statement in ECPG. This is because in ECPG,
+        <literal>DECLARE CURSOR</literal> doesn't translate to a function call into
+        the run-time library that uses to the cursor name. This means that there's no run-time
+        bookkeeping of SQL cursors in the ECPG run-time library, only in the PostgreSQL server.
+       </para>
+      </listitem>
+     </varlistentry>
+     <varlistentry id="ecpg-informix-statements-free-statement-name">
+      <term><literal>FREE statement_name</literal></term>
+      <listitem>
+       <para>
+        <literal>FREE statement_name</literal> is a synonym for <literal>DEALLOCATE PREPARE statement_name</literal>.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-informix-sqlda">
+   <title>Informix-compatible SQLDA Descriptor Areas</title>
+   <para>
+    Informix-compatible mode supports a different structure than the one described in
+    <xref linkend="ecpg-sqlda-descriptors"/>. See below:
+<programlisting>
+struct sqlvar_compat
+{
+    short   sqltype;
+    int     sqllen;
+    char   *sqldata;
+    short  *sqlind;
+    char   *sqlname;
+    char   *sqlformat;
+    short   sqlitype;
+    short   sqlilen;
+    char   *sqlidata;
+    int     sqlxid;
+    char   *sqltypename;
+    short   sqltypelen;
+    short   sqlownerlen;
+    short   sqlsourcetype;
+    char   *sqlownername;
+    int     sqlsourceid;
+    char   *sqlilongdata;
+    int     sqlflags;
+    void   *sqlreserved;
+};
+
+struct sqlda_compat
+{
+    short  sqld;
+    struct sqlvar_compat *sqlvar;
+    char   desc_name[19];
+    short  desc_occ;
+    struct sqlda_compat *desc_next;
+    void  *reserved;
+};
+
+typedef struct sqlvar_compat    sqlvar_t;
+typedef struct sqlda_compat     sqlda_t;
+</programlisting>
+   </para>
+
+   <para>
+    The global properties are:
+    <variablelist>
+
+     <varlistentry id="ecpg-informix-sqlda-sqld">
+     <term><literal>sqld</literal></term>
+      <listitem>
+       <para>
+        The number of fields in the <literal>SQLDA</literal> descriptor.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-sqlvar">
+     <term><literal>sqlvar</literal></term>
+      <listitem>
+       <para>
+        Pointer to the per-field properties.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-desc-name">
+     <term><literal>desc_name</literal></term>
+      <listitem>
+       <para>
+        Unused, filled with zero-bytes.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-desc-occ">
+     <term><literal>desc_occ</literal></term>
+      <listitem>
+       <para>
+        Size of the allocated structure.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-desc-next">
+     <term><literal>desc_next</literal></term>
+      <listitem>
+       <para>
+        Pointer to the next SQLDA structure if the result set contains more than one record.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-reserved">
+     <term><literal>reserved</literal></term>
+      <listitem>
+       <para>
+        Unused pointer, contains NULL. Kept for Informix-compatibility.
+       </para>
+      </listitem>
+     </varlistentry>
+
+    </variablelist>
+
+    The per-field properties are below, they are stored in the <literal>sqlvar</literal> array:
+
+    <variablelist>
+
+     <varlistentry id="ecpg-informix-sqlda-sqltype">
+     <term><literal>sqltype</literal></term>
+      <listitem>
+       <para>
+        Type of the field. Constants are in <literal>sqltypes.h</literal>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-sqllen">
+     <term><literal>sqllen</literal></term>
+      <listitem>
+       <para>
+        Length of the field data.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-sqldata">
+     <term><literal>sqldata</literal></term>
+      <listitem>
+       <para>
+        Pointer to the field data. The pointer is of <literal>char *</literal> type,
+        the data pointed by it is in a binary format. Example:
+<programlisting>
+int intval;
+
+switch (sqldata->sqlvar[i].sqltype)
+{
+    case SQLINTEGER:
+        intval = *(int *)sqldata->sqlvar[i].sqldata;
+        break;
+  ...
+}
+</programlisting>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-sqlind">
+     <term><literal>sqlind</literal></term>
+      <listitem>
+       <para>
+        Pointer to the NULL indicator. If returned by DESCRIBE or FETCH then it's always a valid pointer.
+        If used as input for <literal>EXECUTE ... USING sqlda;</literal> then NULL-pointer value means
+        that the value for this field is non-NULL. Otherwise a valid pointer and <literal>sqlitype</literal>
+        has to be properly set. Example:
+<programlisting>
+if (*(int2 *)sqldata->sqlvar[i].sqlind != 0)
+    printf("value is NULL\n");
+</programlisting>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-sqlname">
+     <term><literal>sqlname</literal></term>
+      <listitem>
+       <para>
+        Name of the field. 0-terminated string.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-sqlformat">
+     <term><literal>sqlformat</literal></term>
+      <listitem>
+       <para>
+        Reserved in Informix, value of <xref linkend="libpq-PQfformat"/> for the field.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-sqlitype">
+     <term><literal>sqlitype</literal></term>
+      <listitem>
+       <para>
+        Type of the NULL indicator data. It's always SQLSMINT when returning data from the server.
+        When the <literal>SQLDA</literal> is used for a parameterized query, the data is treated
+        according to the set type.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-sqlilen">
+     <term><literal>sqlilen</literal></term>
+      <listitem>
+       <para>
+        Length of the NULL indicator data.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-sqlxid">
+     <term><literal>sqlxid</literal></term>
+      <listitem>
+       <para>
+        Extended type of the field, result of <xref linkend="libpq-PQftype"/>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-sqltypename">
+     <term><literal>sqltypename</literal></term>
+     <term><literal>sqltypelen</literal></term>
+     <term><literal>sqlownerlen</literal></term>
+     <term><literal>sqlsourcetype</literal></term>
+     <term><literal>sqlownername</literal></term>
+     <term><literal>sqlsourceid</literal></term>
+     <term><literal>sqlflags</literal></term>
+     <term><literal>sqlreserved</literal></term>
+      <listitem>
+       <para>
+        Unused.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-sqlda-sqlilongdata">
+     <term><literal>sqlilongdata</literal></term>
+      <listitem>
+       <para>
+        It equals to <literal>sqldata</literal> if <literal>sqllen</literal> is larger than 32kB.
+       </para>
+      </listitem>
+     </varlistentry>
+
+    </variablelist>
+
+    Example:
+<programlisting>
+EXEC SQL INCLUDE sqlda.h;
+
+    sqlda_t        *sqlda; /* This doesn't need to be under embedded DECLARE SECTION */
+
+    EXEC SQL BEGIN DECLARE SECTION;
+    char *prep_stmt = "select * from table1";
+    int i;
+    EXEC SQL END DECLARE SECTION;
+
+    ...
+
+    EXEC SQL PREPARE mystmt FROM :prep_stmt;
+
+    EXEC SQL DESCRIBE mystmt INTO sqlda;
+
+    printf("# of fields: %d\n", sqlda-&gt;sqld);
+    for (i = 0; i &lt; sqlda-&gt;sqld; i++)
+      printf("field %d: \"%s\"\n", sqlda-&gt;sqlvar[i]-&gt;sqlname);
+
+    EXEC SQL DECLARE mycursor CURSOR FOR mystmt;
+    EXEC SQL OPEN mycursor;
+    EXEC SQL WHENEVER NOT FOUND GOTO out;
+
+    while (1)
+    {
+      EXEC SQL FETCH mycursor USING sqlda;
+    }
+
+    EXEC SQL CLOSE mycursor;
+
+    free(sqlda); /* The main structure is all to be free(),
+                  * sqlda and sqlda-&gt;sqlvar is in one allocated area */
+</programlisting>
+    For more information, see the <literal>sqlda.h</literal> header and the
+    <literal>src/interfaces/ecpg/test/compat_informix/sqlda.pgc</literal> regression test.
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-informix-functions">
+   <title>Additional Functions</title>
+   <para>
+    <variablelist>
+     <varlistentry id="ecpg-informix-functions-decadd">
+      <term><function>decadd</function></term>
+      <listitem>
+       <para>
+        Add two decimal type values.
+<synopsis>
+int decadd(decimal *arg1, decimal *arg2, decimal *sum);
+</synopsis>
+        The function receives a pointer to the first operand of type decimal
+        (<literal>arg1</literal>), a pointer to the second operand of type decimal
+        (<literal>arg2</literal>) and a pointer to a value of type decimal that will
+        contain the sum (<literal>sum</literal>). On success, the function returns 0.
+        <symbol>ECPG_INFORMIX_NUM_OVERFLOW</symbol> is returned in case of overflow and
+        <symbol>ECPG_INFORMIX_NUM_UNDERFLOW</symbol> in case of underflow. -1 is returned for
+        other failures and <varname>errno</varname> is set to the respective <varname>errno</varname> number of the
+        pgtypeslib.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-deccmp">
+      <term><function>deccmp</function></term>
+      <listitem>
+       <para>
+        Compare two variables of type decimal.
+<synopsis>
+int deccmp(decimal *arg1, decimal *arg2);
+</synopsis>
+        The function receives a pointer to the first decimal value
+        (<literal>arg1</literal>), a pointer to the second decimal value
+        (<literal>arg2</literal>) and returns an integer value that indicates which is
+        the bigger value.
+        <itemizedlist>
+         <listitem>
+          <para>
+           1, if the value that <literal>arg1</literal> points to is bigger than the
+           value that <literal>var2</literal> points to
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           -1, if the value that <literal>arg1</literal> points to is smaller than the
+           value that <literal>arg2</literal> points to </para>
+         </listitem>
+         <listitem>
+          <para>
+           0, if the value that <literal>arg1</literal> points to and the value that
+           <literal>arg2</literal> points to are equal
+          </para>
+         </listitem>
+        </itemizedlist>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-deccopy">
+      <term><function>deccopy</function></term>
+      <listitem>
+       <para>
+        Copy a decimal value.
+<synopsis>
+void deccopy(decimal *src, decimal *target);
+</synopsis>
+        The function receives a pointer to the decimal value that should be
+        copied as the first argument (<literal>src</literal>) and a pointer to the
+        target structure of type decimal (<literal>target</literal>) as the second
+        argument.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-deccvasc">
+      <term><function>deccvasc</function></term>
+      <listitem>
+       <para>
+        Convert a value from its ASCII representation into a decimal type.
+<synopsis>
+int deccvasc(char *cp, int len, decimal *np);
+</synopsis>
+        The function receives a pointer to string that contains the string
+        representation of the number to be converted (<literal>cp</literal>) as well
+        as its length <literal>len</literal>. <literal>np</literal> is a pointer to the
+        decimal value that saves the result of the operation.
+       </para>
+       <para>
+        Valid formats are for example:
+         <literal>-2</literal>,
+         <literal>.794</literal>,
+         <literal>+3.44</literal>,
+         <literal>592.49E07</literal> or
+         <literal>-32.84e-4</literal>.
+       </para>
+       <para>
+        The function returns 0 on success. If overflow or underflow occurred,
+        <literal>ECPG_INFORMIX_NUM_OVERFLOW</literal> or
+        <literal>ECPG_INFORMIX_NUM_UNDERFLOW</literal> is returned. If the ASCII
+        representation could not be parsed,
+        <literal>ECPG_INFORMIX_BAD_NUMERIC</literal> is returned or
+        <literal>ECPG_INFORMIX_BAD_EXPONENT</literal> if this problem occurred while
+        parsing the exponent.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-deccvdbl">
+      <term><function>deccvdbl</function></term>
+      <listitem>
+       <para>
+        Convert a value of type double to a value of type decimal.
+<synopsis>
+int deccvdbl(double dbl, decimal *np);
+</synopsis>
+        The function receives the variable of type double that should be
+        converted as its first argument (<literal>dbl</literal>). As the second
+        argument (<literal>np</literal>), the function receives a pointer to the
+        decimal variable that should hold the result of the operation.
+       </para>
+       <para>
+        The function returns 0 on success and a negative value if the
+        conversion failed.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-deccvint">
+      <term><function>deccvint</function></term>
+      <listitem>
+       <para>
+        Convert a value of type int to a value of type decimal.
+<synopsis>
+int deccvint(int in, decimal *np);
+</synopsis>
+        The function receives the variable of type int that should be
+        converted as its first argument (<literal>in</literal>). As the second
+        argument (<literal>np</literal>), the function receives a pointer to the
+        decimal variable that should hold the result of the operation.
+       </para>
+       <para>
+        The function returns 0 on success and a negative value if the
+        conversion failed.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-deccvlong">
+      <term><function>deccvlong</function></term>
+      <listitem>
+       <para>
+        Convert a value of type long to a value of type decimal.
+<synopsis>
+int deccvlong(long lng, decimal *np);
+</synopsis>
+        The function receives the variable of type long that should be
+        converted as its first argument (<literal>lng</literal>). As the second
+        argument (<literal>np</literal>), the function receives a pointer to the
+        decimal variable that should hold the result of the operation.
+       </para>
+       <para>
+        The function returns 0 on success and a negative value if the
+        conversion failed.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-decdiv">
+      <term><function>decdiv</function></term>
+      <listitem>
+       <para>
+        Divide two variables of type decimal.
+<synopsis>
+int decdiv(decimal *n1, decimal *n2, decimal *result);
+</synopsis>
+        The function receives pointers to the variables that are the first
+        (<literal>n1</literal>) and the second (<literal>n2</literal>) operands and
+        calculates <literal>n1</literal>/<literal>n2</literal>. <literal>result</literal> is a
+        pointer to the variable that should hold the result of the operation.
+       </para>
+       <para>
+        On success, 0 is returned and a negative value if the division fails.
+        If overflow or underflow occurred, the function returns
+        <literal>ECPG_INFORMIX_NUM_OVERFLOW</literal> or
+        <literal>ECPG_INFORMIX_NUM_UNDERFLOW</literal> respectively. If an attempt to
+        divide by zero is observed, the function returns
+        <literal>ECPG_INFORMIX_DIVIDE_ZERO</literal>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-decmul">
+      <term><function>decmul</function></term>
+      <listitem>
+       <para>
+        Multiply two decimal values.
+<synopsis>
+int decmul(decimal *n1, decimal *n2, decimal *result);
+</synopsis>
+        The function receives pointers to the variables that are the first
+        (<literal>n1</literal>) and the second (<literal>n2</literal>) operands and
+        calculates <literal>n1</literal>*<literal>n2</literal>. <literal>result</literal> is a
+        pointer to the variable that should hold the result of the operation.
+       </para>
+       <para>
+        On success, 0 is returned and a negative value if the multiplication
+        fails. If overflow or underflow occurred, the function returns
+        <literal>ECPG_INFORMIX_NUM_OVERFLOW</literal> or
+        <literal>ECPG_INFORMIX_NUM_UNDERFLOW</literal> respectively.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-decsub">
+      <term><function>decsub</function></term>
+      <listitem>
+       <para>
+        Subtract one decimal value from another.
+<synopsis>
+int decsub(decimal *n1, decimal *n2, decimal *result);
+</synopsis>
+        The function receives pointers to the variables that are the first
+        (<literal>n1</literal>) and the second (<literal>n2</literal>) operands and
+        calculates <literal>n1</literal>-<literal>n2</literal>. <literal>result</literal> is a
+        pointer to the variable that should hold the result of the operation.
+       </para>
+       <para>
+        On success, 0 is returned and a negative value if the subtraction
+        fails. If overflow or underflow occurred, the function returns
+        <literal>ECPG_INFORMIX_NUM_OVERFLOW</literal> or
+        <literal>ECPG_INFORMIX_NUM_UNDERFLOW</literal> respectively.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-dectoasc">
+      <term><function>dectoasc</function></term>
+      <listitem>
+       <para>
+        Convert a variable of type decimal to its ASCII representation in a C
+        char* string.
+<synopsis>
+int dectoasc(decimal *np, char *cp, int len, int right)
+</synopsis>
+        The function receives a pointer to a variable of type decimal
+        (<literal>np</literal>) that it converts to its textual representation.
+        <literal>cp</literal> is the buffer that should hold the result of the
+        operation. The parameter <literal>right</literal> specifies, how many digits
+        right of the decimal point should be included in the output. The result
+        will be rounded to this number of decimal digits. Setting
+        <literal>right</literal> to -1 indicates that all available decimal digits
+        should be included in the output. If the length of the output buffer,
+        which is indicated by <literal>len</literal> is not sufficient to hold the
+        textual representation including the trailing zero byte, only a
+        single <literal>*</literal> character is stored in the result and -1 is
+        returned.
+       </para>
+       <para>
+        The function returns either -1 if the buffer <literal>cp</literal> was too
+        small or <literal>ECPG_INFORMIX_OUT_OF_MEMORY</literal> if memory was
+        exhausted.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-dectodbl">
+      <term><function>dectodbl</function></term>
+      <listitem>
+       <para>
+        Convert a variable of type decimal to a double.
+<synopsis>
+int dectodbl(decimal *np, double *dblp);
+</synopsis>
+        The function receives a pointer to the decimal value to convert
+        (<literal>np</literal>) and a pointer to the double variable that
+        should hold the result of the operation (<literal>dblp</literal>).
+       </para>
+       <para>
+        On success, 0 is returned and a negative value if the conversion
+        failed.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-dectoint">
+      <term><function>dectoint</function></term>
+      <listitem>
+       <para>
+        Convert a variable to type decimal to an integer.
+<synopsis>
+int dectoint(decimal *np, int *ip);
+</synopsis>
+        The function receives a pointer to the decimal value to convert
+        (<literal>np</literal>) and a pointer to the integer variable that
+        should hold the result of the operation (<literal>ip</literal>).
+       </para>
+       <para>
+        On success, 0 is returned and a negative value if the conversion
+        failed. If an overflow occurred, <literal>ECPG_INFORMIX_NUM_OVERFLOW</literal>
+        is returned.
+       </para>
+       <para>
+        Note that the ECPG implementation differs from the <productname>Informix</productname>
+        implementation. <productname>Informix</productname> limits an integer to the range from -32767 to
+        32767, while the limits in the ECPG implementation depend on the
+        architecture (<literal>INT_MIN .. INT_MAX</literal>).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-dectolong">
+      <term><function>dectolong</function></term>
+      <listitem>
+       <para>
+        Convert a variable to type decimal to a long integer.
+<synopsis>
+int dectolong(decimal *np, long *lngp);
+</synopsis>
+        The function receives a pointer to the decimal value to convert
+        (<literal>np</literal>) and a pointer to the long variable that
+        should hold the result of the operation (<literal>lngp</literal>).
+       </para>
+       <para>
+        On success, 0 is returned and a negative value if the conversion
+        failed. If an overflow occurred, <literal>ECPG_INFORMIX_NUM_OVERFLOW</literal>
+        is returned.
+       </para>
+       <para>
+        Note that the ECPG implementation differs from the <productname>Informix</productname>
+        implementation. <productname>Informix</productname> limits a long integer to the range from
+        -2,147,483,647 to 2,147,483,647, while the limits in the ECPG
+        implementation depend on the architecture (<literal>-LONG_MAX ..
+        LONG_MAX</literal>).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rdatestr">
+      <term><function>rdatestr</function></term>
+      <listitem>
+       <para>
+        Converts a date to a C char* string.
+<synopsis>
+int rdatestr(date d, char *str);
+</synopsis>
+        The function receives two arguments, the first one is the date to
+        convert (<literal>d</literal>) and the second one is a pointer to the target
+        string. The output format is always <literal>yyyy-mm-dd</literal>, so you need
+        to allocate at least 11 bytes (including the zero-byte terminator) for the
+        string.
+       </para>
+       <para>
+        The function returns 0 on success and a negative value in case of
+        error.
+       </para>
+       <para>
+        Note that ECPG's implementation differs from the <productname>Informix</productname>
+        implementation. In <productname>Informix</productname> the format can be influenced by setting
+        environment variables. In ECPG however, you cannot change the output
+        format.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rstrdate">
+      <term><function>rstrdate</function></term>
+      <listitem>
+       <para>
+        Parse the textual representation of a date.
+<synopsis>
+int rstrdate(char *str, date *d);
+</synopsis>
+        The function receives the textual representation of the date to convert
+        (<literal>str</literal>) and a pointer to a variable of type date
+        (<literal>d</literal>). This function does not allow you to specify a format
+        mask. It uses the default format mask of <productname>Informix</productname> which is
+        <literal>mm/dd/yyyy</literal>. Internally, this function is implemented by
+        means of <function>rdefmtdate</function>. Therefore, <function>rstrdate</function> is
+        not faster and if you have the choice you should opt for
+        <function>rdefmtdate</function> which allows you to specify the format mask
+        explicitly.
+       </para>
+       <para>
+        The function returns the same values as <function>rdefmtdate</function>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rtoday">
+      <term><function>rtoday</function></term>
+      <listitem>
+       <para>
+        Get the current date.
+<synopsis>
+void rtoday(date *d);
+</synopsis>
+        The function receives a pointer to a date variable (<literal>d</literal>)
+        that it sets to the current date.
+       </para>
+       <para>
+        Internally this function uses the <xref linkend="pgtypesdatetoday"/>
+        function.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rjulmdy">
+      <term><function>rjulmdy</function></term>
+      <listitem>
+       <para>
+        Extract the values for the day, the month and the year from a variable
+        of type date.
+<synopsis>
+int rjulmdy(date d, short mdy[3]);
+</synopsis>
+        The function receives the date <literal>d</literal> and a pointer to an array
+        of 3 short integer values <literal>mdy</literal>. The variable name indicates
+        the sequential order: <literal>mdy[0]</literal> will be set to contain the
+        number of the month, <literal>mdy[1]</literal> will be set to the value of the
+        day and <literal>mdy[2]</literal> will contain the year.
+       </para>
+       <para>
+        The function always returns 0 at the moment.
+       </para>
+       <para>
+        Internally the function uses the <xref linkend="pgtypesdatejulmdy"/>
+        function.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rdefmtdate">
+      <term><function>rdefmtdate</function></term>
+      <listitem>
+       <para>
+        Use a format mask to convert a character string to a value of type
+        date.
+<synopsis>
+int rdefmtdate(date *d, char *fmt, char *str);
+</synopsis>
+        The function receives a pointer to the date value that should hold the
+        result of the operation (<literal>d</literal>), the format mask to use for
+        parsing the date (<literal>fmt</literal>) and the C char* string containing
+        the textual representation of the date (<literal>str</literal>). The textual
+        representation is expected to match the format mask. However you do not
+        need to have a 1:1 mapping of the string to the format mask. The
+        function only analyzes the sequential order and looks for the literals
+        <literal>yy</literal> or <literal>yyyy</literal> that indicate the
+        position of the year, <literal>mm</literal> to indicate the position of
+        the month and <literal>dd</literal> to indicate the position of the
+        day.
+       </para>
+       <para>
+        The function returns the following values:
+        <itemizedlist>
+         <listitem>
+          <para>
+           0 - The function terminated successfully.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>ECPG_INFORMIX_ENOSHORTDATE</literal> - The date does not contain
+           delimiters between day, month and year. In this case the input
+           string must be exactly 6 or 8 bytes long but isn't.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>ECPG_INFORMIX_ENOTDMY</literal> - The format string did not
+           correctly indicate the sequential order of year, month and day.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>ECPG_INFORMIX_BAD_DAY</literal> - The input string does not
+           contain a valid day.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>ECPG_INFORMIX_BAD_MONTH</literal> - The input string does not
+           contain a valid month.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>ECPG_INFORMIX_BAD_YEAR</literal> - The input string does not
+           contain a valid year.
+          </para>
+         </listitem>
+        </itemizedlist>
+       </para>
+       <para>
+        Internally this function is implemented to use the <xref
+        linkend="pgtypesdatedefmtasc"/> function. See the reference there for a
+        table of example input.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rfmtdate">
+      <term><function>rfmtdate</function></term>
+      <listitem>
+       <para>
+        Convert a variable of type date to its textual representation using a
+        format mask.
+<synopsis>
+int rfmtdate(date d, char *fmt, char *str);
+</synopsis>
+        The function receives the date to convert (<literal>d</literal>), the format
+        mask (<literal>fmt</literal>) and the string that will hold the textual
+        representation of the date (<literal>str</literal>).
+       </para>
+       <para>
+        On success, 0 is returned and a negative value if an error occurred.
+       </para>
+       <para>
+        Internally this function uses the <xref linkend="pgtypesdatefmtasc"/>
+        function, see the reference there for examples.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rmdyjul">
+      <term><function>rmdyjul</function></term>
+      <listitem>
+       <para>
+        Create a date value from an array of 3 short integers that specify the
+        day, the month and the year of the date.
+<synopsis>
+int rmdyjul(short mdy[3], date *d);
+</synopsis>
+        The function receives the array of the 3 short integers
+        (<literal>mdy</literal>) and a pointer to a variable of type date that should
+        hold the result of the operation.
+       </para>
+       <para>
+        Currently the function returns always 0.
+       </para>
+       <para>
+        Internally the function is implemented to use the function <xref
+        linkend="pgtypesdatemdyjul"/>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rdayofweek">
+      <term><function>rdayofweek</function></term>
+      <listitem>
+       <para>
+        Return a number representing the day of the week for a date value.
+<synopsis>
+int rdayofweek(date d);
+</synopsis>
+        The function receives the date variable <literal>d</literal> as its only
+        argument and returns an integer that indicates the day of the week for
+        this date.
+        <itemizedlist>
+         <listitem>
+          <para>
+           0 - Sunday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           1 - Monday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           2 - Tuesday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           3 - Wednesday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           4 - Thursday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           5 - Friday
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           6 - Saturday
+          </para>
+         </listitem>
+        </itemizedlist>
+       </para>
+       <para>
+        Internally the function is implemented to use the function <xref
+        linkend="pgtypesdatedayofweek"/>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-dtcurrent">
+      <term><function>dtcurrent</function></term>
+      <listitem>
+       <para>
+        Retrieve the current timestamp.
+<synopsis>
+void dtcurrent(timestamp *ts);
+</synopsis>
+        The function retrieves the current timestamp and saves it into the
+        timestamp variable that <literal>ts</literal> points to.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-dtcvasc">
+      <term><function>dtcvasc</function></term>
+      <listitem>
+       <para>
+        Parses a timestamp from its textual representation
+        into a timestamp variable.
+<synopsis>
+int dtcvasc(char *str, timestamp *ts);
+</synopsis>
+        The function receives the string to parse (<literal>str</literal>) and a
+        pointer to the timestamp variable that should hold the result of the
+        operation (<literal>ts</literal>).
+       </para>
+       <para>
+        The function returns 0 on success and a negative value in case of
+        error.
+       </para>
+       <para>
+        Internally this function uses the <xref
+        linkend="pgtypestimestampfromasc"/> function. See the reference there
+        for a table with example inputs.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-dtcvfmtasc">
+      <term><function>dtcvfmtasc</function></term>
+      <listitem>
+       <para>
+        Parses a timestamp from its textual representation
+        using a format mask into a timestamp variable.
+<synopsis>
+dtcvfmtasc(char *inbuf, char *fmtstr, timestamp *dtvalue)
+</synopsis>
+        The function receives the string to parse (<literal>inbuf</literal>), the
+        format mask to use (<literal>fmtstr</literal>) and a pointer to the timestamp
+        variable that should hold the result of the operation
+        (<literal>dtvalue</literal>).
+       </para>
+       <para>
+        This function is implemented by means of the <xref
+        linkend="pgtypestimestampdefmtasc"/> function. See the documentation
+        there for a list of format specifiers that can be used.
+       </para>
+       <para>
+        The function returns 0 on success and a negative value in case of
+        error.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-dtsub">
+      <term><function>dtsub</function></term>
+      <listitem>
+       <para>
+        Subtract one timestamp from another and return a variable of type
+        interval.
+<synopsis>
+int dtsub(timestamp *ts1, timestamp *ts2, interval *iv);
+</synopsis>
+        The function will subtract the timestamp variable that <literal>ts2</literal>
+        points to from the timestamp variable that <literal>ts1</literal> points to
+        and will store the result in the interval variable that <literal>iv</literal>
+        points to.
+       </para>
+       <para>
+        Upon success, the function returns 0 and a negative value if an
+        error occurred.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-dttoasc">
+      <term><function>dttoasc</function></term>
+      <listitem>
+       <para>
+        Convert a timestamp variable to a C char* string.
+<synopsis>
+int dttoasc(timestamp *ts, char *output);
+</synopsis>
+        The function receives a pointer to the timestamp variable to convert
+        (<literal>ts</literal>) and the string that should hold the result of the
+        operation (<literal>output</literal>). It converts <literal>ts</literal> to its
+        textual representation according to the SQL standard, which is
+        be <literal>YYYY-MM-DD HH:MM:SS</literal>.
+       </para>
+       <para>
+        Upon success, the function returns 0 and a negative value if an
+        error occurred.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-dttofmtasc">
+      <term><function>dttofmtasc</function></term>
+      <listitem>
+       <para>
+        Convert a timestamp variable to a C char* using a format mask.
+<synopsis>
+int dttofmtasc(timestamp *ts, char *output, int str_len, char *fmtstr);
+</synopsis>
+        The function receives a pointer to the timestamp to convert as its
+        first argument (<literal>ts</literal>), a pointer to the output buffer
+        (<literal>output</literal>), the maximal length that has been allocated for
+        the output buffer (<literal>str_len</literal>) and the format mask to
+        use for the conversion (<literal>fmtstr</literal>).
+       </para>
+       <para>
+        Upon success, the function returns 0 and a negative value if an
+        error occurred.
+       </para>
+       <para>
+        Internally, this function uses the <xref
+        linkend="pgtypestimestampfmtasc"/> function. See the reference there for
+        information on what format mask specifiers can be used.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-intoasc">
+      <term><function>intoasc</function></term>
+      <listitem>
+       <para>
+        Convert an interval variable to a C char* string.
+<synopsis>
+int intoasc(interval *i, char *str);
+</synopsis>
+        The function receives a pointer to the interval variable to convert
+        (<literal>i</literal>) and the string that should hold the result of the
+        operation (<literal>str</literal>). It converts <literal>i</literal> to its
+        textual representation according to the SQL standard, which is
+        be <literal>YYYY-MM-DD HH:MM:SS</literal>.
+       </para>
+       <para>
+        Upon success, the function returns 0 and a negative value if an
+        error occurred.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rfmtlong">
+      <term><function>rfmtlong</function></term>
+      <listitem>
+       <para>
+        Convert a long integer value to its textual representation using a
+        format mask.
+<synopsis>
+int rfmtlong(long lng_val, char *fmt, char *outbuf);
+</synopsis>
+        The function receives the long value <literal>lng_val</literal>, the format
+        mask <literal>fmt</literal> and a pointer to the output buffer
+        <literal>outbuf</literal>. It converts the long value according to the format
+        mask to its textual representation.
+       </para>
+       <para>
+        The format mask can be composed of the following format specifying
+        characters:
+        <itemizedlist>
+         <listitem>
+          <para>
+           <literal>*</literal> (asterisk) - if this position would be blank
+           otherwise, fill it with an asterisk.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>&amp;</literal> (ampersand) - if this position would be
+           blank otherwise, fill it with a zero.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>#</literal> - turn leading zeroes into blanks.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>&lt;</literal> - left-justify the number in the string.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>,</literal> (comma) - group numbers of four or more digits
+           into groups of three digits separated by a comma.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>.</literal> (period) - this character separates the
+           whole-number part of the number from the fractional part.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>-</literal> (minus) - the minus sign appears if the number
+           is a negative value.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>+</literal> (plus) - the plus sign appears if the number is
+           a positive value.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>(</literal> - this replaces the minus sign in front of the
+           negative number. The minus sign will not appear.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>)</literal> - this character replaces the minus and is
+           printed behind the negative value.
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>$</literal> - the currency symbol.
+          </para>
+         </listitem>
+        </itemizedlist>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rupshift">
+      <term><function>rupshift</function></term>
+      <listitem>
+       <para>
+        Convert a string to upper case.
+<synopsis>
+void rupshift(char *str);
+</synopsis>
+        The function receives a pointer to the string and transforms every
+        lower case character to upper case.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-byleng">
+      <term><function>byleng</function></term>
+      <listitem>
+       <para>
+        Return the number of characters in a string without counting trailing
+        blanks.
+<synopsis>
+int byleng(char *str, int len);
+</synopsis>
+        The function expects a fixed-length string as its first argument
+        (<literal>str</literal>) and its length as its second argument
+        (<literal>len</literal>). It returns the number of significant characters,
+        that is the length of the string without trailing blanks.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-ldchar">
+      <term><function>ldchar</function></term>
+      <listitem>
+       <para>
+        Copy a fixed-length string into a null-terminated string.
+<synopsis>
+void ldchar(char *src, int len, char *dest);
+</synopsis>
+        The function receives the fixed-length string to copy
+        (<literal>src</literal>), its length (<literal>len</literal>) and a pointer to the
+        destination memory (<literal>dest</literal>). Note that you need to reserve at
+        least <literal>len+1</literal> bytes for the string that <literal>dest</literal>
+        points to. The function copies at most <literal>len</literal> bytes to the new
+        location (less if the source string has trailing blanks) and adds the
+        null-terminator.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rgetmsg">
+      <term><function>rgetmsg</function></term>
+      <listitem>
+       <para>
+<synopsis>
+int rgetmsg(int msgnum, char *s, int maxsize);
+</synopsis>
+        This function exists but is not implemented at the moment!
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rtypalign">
+      <term><function>rtypalign</function></term>
+      <listitem>
+       <para>
+<synopsis>
+int rtypalign(int offset, int type);
+</synopsis>
+        This function exists but is not implemented at the moment!
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rtypmsize">
+      <term><function>rtypmsize</function></term>
+      <listitem>
+       <para>
+<synopsis>
+int rtypmsize(int type, int len);
+</synopsis>
+        This function exists but is not implemented at the moment!
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-rtypwidth">
+      <term><function>rtypwidth</function></term>
+      <listitem>
+       <para>
+<synopsis>
+int rtypwidth(int sqltype, int sqllen);
+</synopsis>
+        This function exists but is not implemented at the moment!
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="rsetnull">
+      <term><function>rsetnull</function></term>
+      <listitem>
+       <para>
+        Set a variable to NULL.
+<synopsis>
+int rsetnull(int t, char *ptr);
+</synopsis>
+        The function receives an integer that indicates the type of the
+        variable and a pointer to the variable itself that is cast to a C
+        char* pointer.
+       </para>
+       <para>
+        The following types exist:
+        <itemizedlist>
+         <listitem>
+          <para>
+           <literal>CCHARTYPE</literal> - For a variable of type <type>char</type> or <type>char*</type>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>CSHORTTYPE</literal> - For a variable of type <type>short int</type>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>CINTTYPE</literal> - For a variable of type <type>int</type>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>CBOOLTYPE</literal> - For a variable of type <type>boolean</type>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>CFLOATTYPE</literal> - For a variable of type <type>float</type>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>CLONGTYPE</literal> - For a variable of type <type>long</type>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>CDOUBLETYPE</literal> - For a variable of type <type>double</type>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>CDECIMALTYPE</literal> - For a variable of type <type>decimal</type>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>CDATETYPE</literal> - For a variable of type <type>date</type>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <literal>CDTIMETYPE</literal> - For a variable of type <type>timestamp</type>
+          </para>
+         </listitem>
+        </itemizedlist>
+       </para>
+
+       <para>
+        Here is an example of a call to this function:
+<programlisting><![CDATA[
+$char c[] = "abc       ";
+$short s = 17;
+$int i = -74874;
+
+rsetnull(CCHARTYPE, (char *) c);
+rsetnull(CSHORTTYPE, (char *) &s);
+rsetnull(CINTTYPE, (char *) &i);
+]]>
+</programlisting>
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-functions-risnull">
+      <term><function>risnull</function></term>
+      <listitem>
+       <para>
+        Test if a variable is NULL.
+<synopsis>
+int risnull(int t, char *ptr);
+</synopsis>
+        The function receives the type of the variable to test (<literal>t</literal>)
+        as well a pointer to this variable (<literal>ptr</literal>). Note that the
+        latter needs to be cast to a char*. See the function <xref
+        linkend="rsetnull"/> for a list of possible variable types.
+       </para>
+       <para>
+        Here is an example of how to use this function:
+<programlisting><![CDATA[
+$char c[] = "abc       ";
+$short s = 17;
+$int i = -74874;
+
+risnull(CCHARTYPE, (char *) c);
+risnull(CSHORTTYPE, (char *) &s);
+risnull(CINTTYPE, (char *) &i);
+]]>
+</programlisting>
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+  </sect2>
+
+  <sect2 id="ecpg-informix-constants">
+   <title>Additional Constants</title>
+   <para>
+    Note that all constants here describe errors and all of them are defined
+    to represent negative values. In the descriptions of the different
+    constants you can also find the value that the constants represent in the
+    current implementation. However you should not rely on this number. You can
+    however rely on the fact all of them are defined to represent negative
+    values.
+    <variablelist>
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-num-overflow">
+      <term><literal>ECPG_INFORMIX_NUM_OVERFLOW</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if an overflow occurred in a
+        calculation. Internally it is defined as -1200 (the <productname>Informix</productname>
+        definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-num-underflow">
+      <term><literal>ECPG_INFORMIX_NUM_UNDERFLOW</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if an underflow occurred in a calculation.
+        Internally it is defined as -1201 (the <productname>Informix</productname> definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-divide-zero">
+      <term><literal>ECPG_INFORMIX_DIVIDE_ZERO</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if an attempt to divide by zero is
+        observed. Internally it is defined as -1202 (the <productname>Informix</productname> definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-bad-year">
+      <term><literal>ECPG_INFORMIX_BAD_YEAR</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if a bad value for a year was found while
+        parsing a date. Internally it is defined as -1204 (the <productname>Informix</productname>
+        definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-bad-month">
+      <term><literal>ECPG_INFORMIX_BAD_MONTH</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if a bad value for a month was found while
+        parsing a date. Internally it is defined as -1205 (the <productname>Informix</productname>
+        definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-bad-day">
+      <term><literal>ECPG_INFORMIX_BAD_DAY</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if a bad value for a day was found while
+        parsing a date. Internally it is defined as -1206 (the <productname>Informix</productname>
+        definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-enoshortdate">
+      <term><literal>ECPG_INFORMIX_ENOSHORTDATE</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if a parsing routine needs a short date
+        representation but did not get the date string in the right length.
+        Internally it is defined as -1209 (the <productname>Informix</productname> definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-date-convert">
+      <term><literal>ECPG_INFORMIX_DATE_CONVERT</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if an error occurred during date
+        formatting.  Internally it is defined as -1210 (the
+        <productname>Informix</productname> definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-out-of-memory">
+      <term><literal>ECPG_INFORMIX_OUT_OF_MEMORY</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if memory was exhausted during
+        their operation.  Internally it is defined as -1211 (the
+        <productname>Informix</productname> definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-enotdmy">
+      <term><literal>ECPG_INFORMIX_ENOTDMY</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if a parsing routine was supposed to get a
+        format mask (like <literal>mmddyy</literal>) but not all fields were listed
+        correctly. Internally it is defined as -1212 (the <productname>Informix</productname> definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-bad-numeric">
+      <term><literal>ECPG_INFORMIX_BAD_NUMERIC</literal></term>
+      <listitem>
+       <para>
+        Functions return this value either if a parsing routine cannot parse
+        the textual representation for a numeric value because it contains
+        errors or if a routine cannot complete a calculation involving numeric
+        variables because at least one of the numeric variables is invalid.
+        Internally it is defined as -1213 (the <productname>Informix</productname> definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-bad-exponent">
+      <term><literal>ECPG_INFORMIX_BAD_EXPONENT</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if a parsing routine cannot parse
+        an exponent.  Internally it is defined as -1216 (the
+        <productname>Informix</productname> definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-bad-date">
+      <term><literal>ECPG_INFORMIX_BAD_DATE</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if a parsing routine cannot parse
+        a date.  Internally it is defined as -1218 (the
+        <productname>Informix</productname> definition).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-informix-constants-ecpg-informix-extra-chars">
+      <term><literal>ECPG_INFORMIX_EXTRA_CHARS</literal></term>
+      <listitem>
+       <para>
+        Functions return this value if a parsing routine is passed extra
+        characters it cannot parse.  Internally it is defined as -1264 (the
+        <productname>Informix</productname> definition).
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+  </sect2>
+ </sect1>
+
+ <sect1 id="ecpg-oracle-compat">
+  <title><productname>Oracle</productname> Compatibility Mode</title>
+  <para>
+   <command>ecpg</command> can be run in a so-called <firstterm>Oracle
+   compatibility mode</firstterm>. If this mode is active, it tries to
+   behave as if it were Oracle <productname>Pro*C</productname>.
+  </para>
+
+  <para>
+   Specifically, this mode changes <command>ecpg</command> in three ways:
+
+   <itemizedlist>
+    <listitem>
+     <para>
+      Pad character arrays receiving character string types with
+      trailing spaces to the specified length
+     </para>
+    </listitem>
+
+    <listitem>
+     <para>
+      Zero byte terminate these character arrays, and set the indicator
+      variable if truncation occurs
+     </para>
+    </listitem>
+
+    <listitem>
+     <para>
+      Set the null indicator to <literal>-1</literal> when character
+      arrays receive empty character string types
+     </para>
+    </listitem>
+   </itemizedlist>
+  </para>
+ </sect1>
+
+ <sect1 id="ecpg-develop">
+  <title>Internals</title>
+
+  <para>
+   This section explains how <application>ECPG</application> works
+   internally. This information can occasionally be useful to help
+   users understand how to use <application>ECPG</application>.
+  </para>
+
+   <para>
+    The first four lines written by <command>ecpg</command> to the
+    output are fixed lines.  Two are comments and two are include
+    lines necessary to interface to the library.  Then the
+    preprocessor reads through the file and writes output.  Normally
+    it just echoes everything to the output.
+   </para>
+
+   <para>
+    When it sees an <command>EXEC SQL</command> statement, it
+    intervenes and changes it. The command starts with <command>EXEC
+    SQL</command> and ends with <command>;</command>. Everything in
+    between is treated as an <acronym>SQL</acronym> statement and
+    parsed for variable substitution.
+   </para>
+
+   <para>
+    Variable substitution occurs when a symbol starts with a colon
+    (<literal>:</literal>). The variable with that name is looked up
+    among the variables that were previously declared within a
+    <literal>EXEC SQL DECLARE</literal> section.
+   </para>
+
+   <para>
+    The most important function in the library is
+    <function>ECPGdo</function>, which takes care of executing most
+    commands. It takes a variable number of arguments. This can easily
+    add up to 50 or so arguments, and we hope this will not be a
+    problem on any platform.
+   </para>
+
+   <para>
+    The arguments are:
+
+    <variablelist>
+     <varlistentry id="ecpg-develop-line-number">
+      <term>A line number</term>
+      <listitem>
+       <para>
+        This is the line number of the original line; used in error
+        messages only.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-develop-string">
+      <term>A string</term>
+      <listitem>
+       <para>
+        This is the <acronym>SQL</acronym> command that is to be issued.
+        It is modified by the input variables, i.e., the variables that
+        where not known at compile time but are to be entered in the
+        command. Where the variables should go the string contains
+        <literal>?</literal>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-develop-input-variables">
+      <term>Input variables</term>
+      <listitem>
+       <para>
+        Every input variable causes ten arguments to be created.  (See below.)
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-develop-ecpgt-eoit">
+      <term><parameter>ECPGt_EOIT</parameter></term>
+      <listitem>
+       <para>
+        An <type>enum</type> telling that there are no more input
+        variables.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="ecpg-develop-output-variables">
+      <term>Output variables</term>
+      <listitem>
+       <para>
+        Every output variable causes ten arguments to be created.
+        (See below.)  These variables are filled by the function.
+       </para>
+      </listitem>
+     </varlistentry>
+
+      <varlistentry id="ecpg-develop-ecpgt-eort">
+       <term><parameter>ECPGt_EORT</parameter></term>
+       <listitem>
+       <para>
+        An <type>enum</type> telling that there are no more variables.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+   </para>
+
+   <para>
+    For every variable that is part of the <acronym>SQL</acronym>
+    command, the function gets ten arguments:
+
+    <orderedlist>
+     <listitem>
+      <para>
+       The type as a special symbol.
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       A pointer to the value or a pointer to the pointer.
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       The size of the variable if it is a <type>char</type> or <type>varchar</type>.
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       The number of elements in the array (for array fetches).
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       The offset to the next element in the array (for array fetches).
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       The type of the indicator variable as a special symbol.
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       A pointer to the indicator variable.
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       0
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       The number of elements in the indicator array (for array fetches).
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       The offset to the next element in the indicator array (for
+       array fetches).
+      </para>
+     </listitem>
+    </orderedlist>
+   </para>
+
+   <para>
+    Note that not all SQL commands are treated in this way.  For
+    instance, an open cursor statement like:
+<programlisting>
+EXEC SQL OPEN <replaceable>cursor</replaceable>;
+</programlisting>
+    is not copied to the output. Instead, the cursor's
+    <command>DECLARE</command> command is used at the position of the <command>OPEN</command> command
+    because it indeed opens the cursor.
+   </para>
+
+   <para>
+    Here is a complete example describing the output of the
+    preprocessor of a file <filename>foo.pgc</filename> (details might
+    change with each particular version of the preprocessor):
+<programlisting>
+EXEC SQL BEGIN DECLARE SECTION;
+int index;
+int result;
+EXEC SQL END DECLARE SECTION;
+...
+EXEC SQL SELECT res INTO :result FROM mytable WHERE index = :index;
+</programlisting>
+    is translated into:
+<programlisting><![CDATA[
+/* Processed by ecpg (2.6.0) */
+/* These two include files are added by the preprocessor */
+#include <ecpgtype.h>;
+#include <ecpglib.h>;
+
+/* exec sql begin declare section */
+
+#line 1 "foo.pgc"
+
+ int index;
+ int result;
+/* exec sql end declare section */
+...
+ECPGdo(__LINE__, NULL, "SELECT res FROM mytable WHERE index = ?     ",
+        ECPGt_int,&(index),1L,1L,sizeof(int),
+        ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EOIT,
+        ECPGt_int,&(result),1L,1L,sizeof(int),
+        ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EORT);
+#line 147 "foo.pgc"
+]]>
+</programlisting>
+    (The indentation here is added for readability and not
+    something the preprocessor does.)
+   </para>
+ </sect1>
+</chapter>