From 27d0dbf013c0b048dd9ff2ce39cfc3e3116d16a3 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Mon, 3 Mar 2008 17:11:23 +0000
Subject: [PATCH] Document that chr(0) is not supported, and why.

---
 doc/src/sgml/func.sgml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6306edb27b..ac9ee81837 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1340,7 +1340,8 @@
         Character with the given code. For <acronym>UTF8</acronym> the
         argument is treated as a Unicode code point. For other multibyte
         encodings the argument must designate a strictly
-        <acronym>ASCII</acronym> character.
+        <acronym>ASCII</acronym> character.  The NULL (0) character is not
+        allowed because text data types cannot reliably store such bytes.
        </entry>
        <entry><literal>chr(65)</literal></entry>
        <entry><literal>A</literal></entry>
-- 
2.39.5