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Document pltcl's return_null command.

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This commit is contained in:
Tom Lane 2001-04-30 22:22:34 +00:00
parent 955c8771f8
commit c8b5598a11
1 changed files with 10 additions and 3 deletions
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13
doc/src/sgml/pltcl.sgml
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@ -1,5 +1,5 @@
<!-- <!--
$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"> <chapter id="pltcl">
@ -96,8 +96,10 @@ CREATE FUNCTION <replaceable>funcname</replaceable> (<replaceable>argument-types
</programlisting> </programlisting>
When the function is called, the arguments are given as When the function is called, the arguments are given as
variables $1 ... $n to the Tcl procedure body. For example, variables <literal>$1</literal> ... <literal>$n</literal> to the
a function 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: returning the higher of two int4 values could be defined as:
<programlisting> <programlisting>
@ -107,6 +109,11 @@ CREATE FUNCTION tcl_max (int4, int4) RETURNS int4 AS '
' LANGUAGE 'pltcl'; ' LANGUAGE 'pltcl';
</programlisting> </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. Composite type arguments are given to the procedure as Tcl arrays.
The element names The element names
in the array are the attribute names of the composite in the array are the attribute names of the composite