diff --git a/chapters/config.xml b/chapters/config.xml
index 19ebb05323..d4e1327506 100644
--- a/chapters/config.xml
+++ b/chapters/config.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.83 $ -->
+<!-- $Revision: 1.84 $ -->
  <chapter id="configuration">
   <title>Configuration</title>
 
@@ -463,7 +463,10 @@ include_path = ".;c:\php\lib"
        <para>
         This sets the maximum amount of memory in bytes that a script
         is allowed to allocate.  This helps prevent poorly written
-        scripts for eating up all available memory on a server.
+        scripts for eating up all available memory on a server.  In order to
+        use this directive you must have enabled it at compile time.  So, 
+        your configure line would have included:
+        <literal>--enable-memory-limit</literal>
        </para>
       </listitem>
      </varlistentry>