<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/pltcl.sgml,v 2.8 2001/03/25 10:16:12 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/pltcl.sgml,v 2.9 2001/04/30 22:22:34 tgl Exp $
-->
<chapter id="pltcl">
</programlisting>
When the function is called, the arguments are given as
- variables $1 ... $n to the Tcl procedure body. For example,
- a function
+ variables <literal>$1</literal> ... <literal>$n</literal> to the
+ Tcl procedure body. The result is returned
+ from the Tcl code in the usual way, with a <literal>return</literal>
+ statement. For example, a function
returning the higher of two int4 values could be defined as:
<programlisting>
' LANGUAGE 'pltcl';
</programlisting>
+ To return a NULL value from a PL/Tcl function, execute
+ <literal>return_null</literal>.
+ </para>
+
+ <para>
Composite type arguments are given to the procedure as Tcl arrays.
The element names
in the array are the attribute names of the composite