From ee56e14bbb6f3593e79c1d7e22b02bbc6df4b500 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 21 Dec 2014 15:30:39 -0500
Subject: [PATCH] Docs: clarify treatment of variadic functions with zero
variadic arguments.
Explain that you have to use "VARIADIC ARRAY[]" to pass an empty array
to a variadic parameter position. This was already implicit in the text
but it seems better to spell it out.
Per a suggestion from David Johnston, though I didn't use his proposed
wording. Back-patch to all supported branches.
---
doc/src/sgml/xfunc.sgml | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml
index e2b10703ee9..66e752c3928 100644
--- a/doc/src/sgml/xfunc.sgml
+++ b/doc/src/sgml/xfunc.sgml
@@ -739,6 +739,20 @@ SELECT mleast(VARIADIC ARRAY[10, -1, 5, 4.4]);
actual argument of a function call.
</para>
+ <para>
+ Specifying <literal>VARIADIC</> in the call is also the only way to
+ pass an empty array to a variadic function, for example:
+
+<screen>
+SELECT mleast(VARIADIC ARRAY[]::numeric[]);
+</screen>
+
+ Simply writing <literal>SELECT mleast()</> does not work because a
+ variadic parameter must match at least one actual argument.
+ (You could define a second function also named <literal>mleast</>,
+ with no parameters, if you wanted to allow such calls.)
+ </para>
+
<para>
The array element parameters generated from a variadic parameter are
treated as not having any names of their own. This means it is not
--
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