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   2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>ecpg</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="app-dropuser.html" title="dropuser" /><link rel="next" href="app-pgamcheck.html" title="pg_amcheck" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center"><span class="application">ecpg</span></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="app-dropuser.html" title="dropuser">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="reference-client.html" title="PostgreSQL Client Applications">Up</a></td><th width="60%" align="center">PostgreSQL Client Applications</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 18.0 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="app-pgamcheck.html" title="pg_amcheck">Next</a></td></tr></table><hr /></div><div class="refentry" id="APP-ECPG"><div class="titlepage"></div><a id="id-1.9.4.8.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle"><span class="application">ecpg</span></span></h2><p><span class="application">ecpg</span> — embedded SQL C preprocessor</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="cmdsynopsis"><p id="id-1.9.4.8.4.1"><code class="command">ecpg</code> [<em class="replaceable"><code>option</code></em>...]  <em class="replaceable"><code>file</code></em>... </p></div></div><div class="refsect1" id="APP-ECPG-DESCRIPTION"><h2>Description</h2><p>
   3    <code class="command">ecpg</code> is the embedded SQL preprocessor for C
   4    programs.  It converts C programs with embedded SQL statements to
   5    normal C code by replacing the SQL invocations with special
   6    function calls.  The output files can then be processed with any C
   7    compiler tool chain.
   8   </p><p>
   9    <code class="command">ecpg</code> will convert each input file given on the
  10    command line to the corresponding C output file.  If an input file
  11    name does not have any extension, <code class="filename">.pgc</code> is
  12    assumed.  The file's extension will be replaced
  13    by <code class="filename">.c</code> to construct the output file name.
  14    But the output file name can be overridden using the
  15    <code class="option">-o</code> option.
  16   </p><p>
  17    If an input file name is just <code class="literal">-</code>,
  18    <code class="command">ecpg</code> reads the program from standard input
  19    (and writes to standard output, unless that is overridden
  20    with <code class="option">-o</code>).
  21   </p><p>
  22    This reference page does not describe the embedded SQL language.
  23    See <a class="xref" href="ecpg.html" title="Chapter 34. ECPG — Embedded SQL in C">Chapter 34</a> for more information on that topic.
  24   </p></div><div class="refsect1" id="id-1.9.4.8.6"><h2>Options</h2><p>
  25    <code class="command">ecpg</code> accepts the following command-line
  26    arguments:
  27
  28    </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">-c</code></span></dt><dd><p>
  29        Automatically generate certain C code from SQL code.  Currently, this
  30        works for <code class="literal">EXEC SQL TYPE</code>.
  31       </p></dd><dt><span class="term"><code class="option">-C <em class="replaceable"><code>mode</code></em></code></span></dt><dd><p>
  32        Set a compatibility mode.  <em class="replaceable"><code>mode</code></em> can
  33        be <code class="literal">INFORMIX</code>,
  34        <code class="literal">INFORMIX_SE</code>, or <code class="literal">ORACLE</code>.
  35       </p></dd><dt><span class="term"><code class="option">-D <em class="replaceable"><code>symbol</code></em>[=<em class="replaceable"><code>value</code></em>]</code></span></dt><dd><p>
  36        Define a preprocessor symbol, equivalently to the <code class="command">EXEC SQL
  37        DEFINE</code> directive.  If no <em class="replaceable"><code>value</code></em> is
  38        specified, the symbol is defined with the value <code class="literal">1</code>.
  39       </p></dd><dt><span class="term"><code class="option">-h</code></span></dt><dd><p>
  40        Process header files.  When this option is specified, the output file
  41        extension becomes <code class="literal">.h</code> not <code class="literal">.c</code>,
  42        and the default input file extension is <code class="literal">.pgh</code>
  43        not <code class="literal">.pgc</code>.  Also, the <code class="option">-c</code> option is
  44        forced on.
  45       </p></dd><dt><span class="term"><code class="option">-i</code></span></dt><dd><p>
  46        Parse system include files as well.
  47       </p></dd><dt><span class="term"><code class="option">-I <em class="replaceable"><code>directory</code></em></code></span></dt><dd><p>
  48        Specify an additional include path, used to find files included
  49        via <code class="literal">EXEC SQL INCLUDE</code>.  Defaults are
  50        <code class="filename">.</code> (current directory),
  51        <code class="filename">/usr/local/include</code>, the
  52        <span class="productname">PostgreSQL</span> include directory which
  53        is defined at compile time (default:
  54        <code class="filename">/usr/local/pgsql/include</code>), and
  55        <code class="filename">/usr/include</code>, in that order.
  56       </p></dd><dt><span class="term"><code class="option">-o <em class="replaceable"><code>filename</code></em></code></span></dt><dd><p>
  57        Specifies that <code class="command">ecpg</code> should write all
  58        its output to the given <em class="replaceable"><code>filename</code></em>.
  59        Write <code class="literal">-o -</code> to send all output to standard output.
  60       </p></dd><dt><span class="term"><code class="option">-r <em class="replaceable"><code>option</code></em></code></span></dt><dd><p>
  61        Selects run-time behavior.  <em class="replaceable"><code>Option</code></em> can be
  62        one of the following:
  63        </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">no_indicator</code></span></dt><dd><p>
  64          Do not use indicators but instead use special values to represent
  65          null values. Historically there have been databases using this approach.
  66          </p></dd><dt><span class="term"><code class="option">prepare</code></span></dt><dd><p>
  67          Prepare all statements before using them. Libecpg will keep a cache of
  68          prepared statements and reuse a statement if it gets executed again. If the
  69          cache runs full, libecpg will free the least used statement.
  70          </p></dd><dt><span class="term"><code class="option">questionmarks</code></span></dt><dd><p>
  71          Allow question mark as placeholder for compatibility reasons.
  72          This used to be the default long ago.
  73          </p></dd></dl></div></dd><dt><span class="term"><code class="option">-t</code></span></dt><dd><p>
  74        Turn on autocommit of transactions. In this mode, each SQL command is
  75        automatically committed unless it is inside an explicit
  76        transaction block. In the default mode, commands are committed
  77        only when <code class="command">EXEC SQL COMMIT</code> is issued.
  78       </p></dd><dt><span class="term"><code class="option">-v</code></span></dt><dd><p>
  79        Print additional information including the version and the
  80        "include" path.
  81       </p></dd><dt><span class="term"><code class="option">--version</code></span></dt><dd><p>
  82        Print the <span class="application">ecpg</span> version and exit.
  83       </p></dd><dt><span class="term"><code class="option">-?</code><br /></span><span class="term"><code class="option">--help</code></span></dt><dd><p>
  84        Show help about <span class="application">ecpg</span> command line
  85        arguments, and exit.
  86       </p></dd></dl></div><p>
  87   </p></div><div class="refsect1" id="id-1.9.4.8.7"><h2>Notes</h2><p>
  88    When compiling the preprocessed C code files, the compiler needs to
  89    be able to find the <span class="application">ECPG</span> header files in the
  90    <span class="productname">PostgreSQL</span> include directory.  Therefore, you might
  91    have to use the <code class="option">-I</code> option when invoking the compiler
  92    (e.g., <code class="literal">-I/usr/local/pgsql/include</code>).
  93   </p><p>
  94    Programs using C code with embedded SQL have to be linked against
  95    the <code class="filename">libecpg</code> library, for example using the
  96    linker options <code class="literal">-L/usr/local/pgsql/lib -lecpg</code>.
  97   </p><p>
  98    The value of either of these directories that is appropriate for
  99    the installation can be found out using <a class="xref" href="app-pgconfig.html" title="pg_config"><span class="refentrytitle"><span class="application">pg_config</span></span></a>.
 100   </p></div><div class="refsect1" id="id-1.9.4.8.8"><h2>Examples</h2><p>
 101    If you have an embedded SQL C source file named
 102    <code class="filename">prog1.pgc</code>, you can create an executable
 103    program using the following sequence of commands:
 104 </p><pre class="programlisting">
 105 ecpg prog1.pgc
 106 cc -I/usr/local/pgsql/include -c prog1.c
 107 cc -o prog1 prog1.o -L/usr/local/pgsql/lib -lecpg
 108 </pre></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="app-dropuser.html" title="dropuser">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="reference-client.html" title="PostgreSQL Client Applications">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="app-pgamcheck.html" title="pg_amcheck">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="application">dropuser</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 18.0 Documentation">Home</a></td><td width="40%" align="right" valign="top"> <span class="application">pg_amcheck</span></td></tr></table></div></body></html>