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Add documentation section "Using C++ for Extensibility".

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Craig Ringer
This commit is contained in:
Bruce Momjian 2010-06-01 02:31:36 +00:00
parent 309193bbd3
commit b67fbb6c57
1 changed files with 47 additions and 1 deletions
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doc/src/sgml/extend.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/extend.sgml,v 1.38 2010/04/03 07:22:53 petere Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/extend.sgml,v 1.39 2010/06/01 02:31:36 momjian Exp $ -->
<chapter id="extend">
<title>Extending <acronym>SQL</acronym></title>
@ -273,4 +273,50 @@
&xoper;
&xindex;
<sect1 id="extend-how">
<title>Using C++ for Extensibility</title>
<indexterm zone="extend-Cpp">
<primary>C++</primary>
</indexterm>
<para>
It is possible to use a compiler in C++ mode to build
<productname>PostgreSQL</productname> extensions; you must simply
follow the standard methods for dynamically linking to C executables:
<itemizedlist>
<listitem>
<para>
Use <literal>extern C</> linkage for all functions that must
be accessible by <function>dlopen()</>. This is also necessary
for any functions that might be passed as pointers between
the backend and C++ code.
</para>
</listitem>
<listitem>
<para>
Use <function>malloc()</> to allocate any memory that might be
freed by the backend C code (don't pass <function>new()</>-allocated
memory).
</para>
</listitem>
<listitem>
<para>
Use <function>free()</> to free memory allocated by the backend
C code (do not use <function>delete()</> for such cases).
</para>
</listitem>
<listitem>
<para>
Prevent exceptions from propagating into the C code (use a
catch-all block at the top level of all <literal>extern C</>
functions).
</para>
</listitem>
</itemizedlist>
</para>
</sect1>
</chapter>