<indexterm><primary>macOS</primary><secondary>shared library</secondary></indexterm>
    </term>
    <listitem>
     <para>
      Here is an example.  It assumes the developer tools are installed.
<programlisting>
cc -c foo.c
cc -bundle -flat_namespace -undefined suppress -o foo.so foo.o
</programlisting>
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     <systemitem class="osname">NetBSD</systemitem>
     <indexterm><primary>NetBSD</primary><secondary>shared library</secondary></indexterm>
    </term>
    <listitem>
     <para>
      The compiler flag to create <acronym>PIC</acronym> is
      <option>-fPIC</option>.  For <acronym>ELF</acronym> systems, the
      compiler with the flag <option>-shared</option> is used to link
      shared libraries.  On the older non-ELF systems, <literal>ld
      -Bshareable</literal> is used.
<programlisting>
gcc -fPIC -c foo.c
gcc -shared -o foo.so foo.o
</programlisting>
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     <systemitem class="osname">OpenBSD</systemitem>
     <indexterm><primary>OpenBSD</primary><secondary>shared library</secondary></indexterm>
    </term>
    <listitem>
     <para>
      The compiler flag to create <acronym>PIC</acronym> is
      <option>-fPIC</option>.  <literal>ld -Bshareable</literal> is
      used to link shared libraries.
<programlisting>
gcc -fPIC -c foo.c
ld -Bshareable -o foo.so foo.o
</programlisting>
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     <systemitem class="osname">Solaris</systemitem>
     <indexterm><primary>Solaris</primary><secondary>shared library</secondary></indexterm>
    </term>
    <listitem>
     <para>
      The compiler flag to create <acronym>PIC</acronym> is
      <option>-KPIC</option> with the Sun compiler and
      <option>-fPIC</option> with <application>GCC</application>.  To
      link shared libraries, the compiler option is
      <option>-G</option> with either compiler or alternatively
      <option>-shared</option> with <application>GCC</application>.
<programlisting>
cc -KPIC -c foo.c
cc -G -o foo.so foo.o
</programlisting>
      or
<programlisting>
gcc -fPIC -c foo.c
gcc -G -o foo.so foo.o
</programlisting>
     </para>
    </listitem>
   </varlistentry>

  </variablelist>

 <tip>
  <para>
   If this is too complicated for you, you should consider using
   <ulink url="https://www.gnu.org/software/libtool/">
   <productname>GNU Libtool</productname></ulink>,
   which hides the platform differences behind a uniform interface.
  </para>
 </tip>

 <para>
  The resulting shared library file can then be loaded into
  <productname>PostgreSQL</productname>.  When specifying the file name
  to the <command>CREATE FUNCTION</command> command, one must give it
  the name of the shared library file, not the intermediate object file.
  Note that the system's standard shared-library extension (usually
  <literal>.so</literal> or <literal>.sl</literal>) can be omitted from
  the <command>CREATE FUNCTION</command> command, and normally should
  be omitted for best portability.
 </para>

 <para>
  Refer back to <xref linkend="xfunc-c-dynload"/> about where the
  server expects to find the shared library files.
 </para>

</sect2>