diff --git a/reference/pcre/book.xml b/reference/pcre/book.xml
index b63fbf5818..e07522cf38 100644
--- a/reference/pcre/book.xml
+++ b/reference/pcre/book.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.6 $ -->
+<!-- $Revision: 1.7 $ -->
 <!-- Purpose: basic.text -->
 <!-- Membership: bundled -->
 
@@ -13,10 +13,11 @@
    The syntax for patterns used in these functions closely resembles
    Perl. The expression must be enclosed in the delimiters, a
    forward slash (/), for example.  Any character can be used for
-   delimiter as long as it's not alphanumeric or backslash (\). If
-   the delimiter character has to be used in the expression itself,
-   it needs to be escaped by backslash. Since PHP 4.0.4, you can also use
-   Perl-style (), {}, [], and &lt;&gt; matching delimiters.
+   delimiter as long as it's not alphanumeric, backslash (\), or the
+   null byte. If the delimiter character has to be used in the 
+   expression itself, it needs to be escaped by backslash. Since PHP
+   4.0.4, you can also use Perl-style (), {}, [], and &lt;&gt;
+   matching delimiters.
    See <link linkend="reference.pcre.pattern.syntax">Pattern Syntax</link>
    for detailed explanation.
   </para>