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diff --git a/doc/src/sgml/html/libpq-build.html b/doc/src/sgml/html/libpq-build.html new file mode 100644 index 0000000..622d511 --- /dev/null +++ b/doc/src/sgml/html/libpq-build.html @@ -0,0 +1,106 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!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>34.21. Building libpq Programs</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="libpq-threading.html" title="34.20. Behavior in Threaded Programs" /><link rel="next" href="libpq-example.html" title="34.22. Example Programs" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">34.21. Building <span class="application">libpq</span> Programs</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="libpq-threading.html" title="34.20. Behavior in Threaded Programs">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="libpq.html" title="Chapter 34. libpq — C Library">Up</a></td><th width="60%" align="center">Chapter 34. <span class="application">libpq</span> — C Library</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="libpq-example.html" title="34.22. Example Programs">Next</a></td></tr></table><hr /></div><div class="sect1" id="LIBPQ-BUILD"><div class="titlepage"><div><div><h2 class="title" style="clear: both">34.21. Building <span class="application">libpq</span> Programs <a href="#LIBPQ-BUILD" class="id_link">#</a></h2></div></div></div><a id="id-1.7.3.28.2" class="indexterm"></a><p> + To build (i.e., compile and link) a program using + <span class="application">libpq</span> you need to do all of the following + things: + + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p> + Include the <code class="filename">libpq-fe.h</code> header file: +</p><pre class="programlisting"> +#include <libpq-fe.h> +</pre><p> + If you failed to do that then you will normally get error messages + from your compiler similar to: +</p><pre class="screen"> +foo.c: In function `main': +foo.c:34: `PGconn' undeclared (first use in this function) +foo.c:35: `PGresult' undeclared (first use in this function) +foo.c:54: `CONNECTION_BAD' undeclared (first use in this function) +foo.c:68: `PGRES_COMMAND_OK' undeclared (first use in this function) +foo.c:95: `PGRES_TUPLES_OK' undeclared (first use in this function) +</pre><p> + </p></li><li class="listitem"><p> + Point your compiler to the directory where the <span class="productname">PostgreSQL</span> header + files were installed, by supplying the + <code class="literal">-I<em class="replaceable"><code>directory</code></em></code> option + to your compiler. (In some cases the compiler will look into + the directory in question by default, so you can omit this + option.) For instance, your compile command line could look + like: +</p><pre class="programlisting"> +cc -c -I/usr/local/pgsql/include testprog.c +</pre><p> + If you are using makefiles then add the option to the + <code class="varname">CPPFLAGS</code> variable: +</p><pre class="programlisting"> +CPPFLAGS += -I/usr/local/pgsql/include +</pre><p> + </p><p> + If there is any chance that your program might be compiled by + other users then you should not hardcode the directory location + like that. Instead, you can run the utility + <code class="command">pg_config</code><a id="id-1.7.3.28.3.2.2.2.2" class="indexterm"></a> to find out where the header + files are on the local system: +</p><pre class="screen"> +<code class="prompt">$</code> pg_config --includedir +<code class="computeroutput">/usr/local/include</code> +</pre><p> + </p><p> + If you + have <code class="command">pkg-config</code><a id="id-1.7.3.28.3.2.2.3.2" class="indexterm"></a> installed, you can run instead: +</p><pre class="screen"> +<code class="prompt">$</code> pkg-config --cflags libpq +<code class="computeroutput">-I/usr/local/include</code> +</pre><p> + Note that this will already include the <code class="option">-I</code> in front of + the path. + </p><p> + Failure to specify the correct option to the compiler will + result in an error message such as: +</p><pre class="screen"> +testlibpq.c:8:22: libpq-fe.h: No such file or directory +</pre><p> + </p></li><li class="listitem"><p> + When linking the final program, specify the option + <code class="literal">-lpq</code> so that the <span class="application">libpq</span> + library gets pulled in, as well as the option + <code class="literal">-L<em class="replaceable"><code>directory</code></em></code> to point + the compiler to the directory where the + <span class="application">libpq</span> library resides. (Again, the + compiler will search some directories by default.) For maximum + portability, put the <code class="option">-L</code> option before the + <code class="option">-lpq</code> option. For example: +</p><pre class="programlisting"> +cc -o testprog testprog1.o testprog2.o -L/usr/local/pgsql/lib -lpq +</pre><p> + </p><p> + You can find out the library directory using + <code class="command">pg_config</code> as well: +</p><pre class="screen"> +<code class="prompt">$</code> pg_config --libdir +<code class="computeroutput">/usr/local/pgsql/lib</code> +</pre><p> + </p><p> + Or again use <code class="command">pkg-config</code>: +</p><pre class="screen"> +<code class="prompt">$</code> pkg-config --libs libpq +<code class="computeroutput">-L/usr/local/pgsql/lib -lpq</code> +</pre><p> + Note again that this prints the full options, not only the path. + </p><p> + Error messages that point to problems in this area could look like + the following: +</p><pre class="screen"> +testlibpq.o: In function `main': +testlibpq.o(.text+0x60): undefined reference to `PQsetdbLogin' +testlibpq.o(.text+0x71): undefined reference to `PQstatus' +testlibpq.o(.text+0xa4): undefined reference to `PQerrorMessage' +</pre><p> + This means you forgot <code class="option">-lpq</code>. +</p><pre class="screen"> +/usr/bin/ld: cannot find -lpq +</pre><p> + This means you forgot the <code class="option">-L</code> option or did not + specify the right directory. + </p></li></ul></div><p> + </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="libpq-threading.html" title="34.20. Behavior in Threaded Programs">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="libpq.html" title="Chapter 34. libpq — C Library">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="libpq-example.html" title="34.22. Example Programs">Next</a></td></tr><tr><td width="40%" align="left" valign="top">34.20. Behavior in Threaded Programs </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 34.22. Example Programs</td></tr></table></div></body></html>
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