diff --git a/reference/readline/functions/readline-completion-function.xml b/reference/readline/functions/readline-completion-function.xml
index 9a67fb0058..f0752f2c51 100644
--- a/reference/readline/functions/readline-completion-function.xml
+++ b/reference/readline/functions/readline-completion-function.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.3 $ -->
+<!-- $Revision: 1.4 $ -->
 <!-- splitted from ./en/functions/readline.xml, last change in rev 1.1 -->
   <refentry id="function.readline-completion-function">
    <refnamediv>
@@ -10,7 +10,7 @@
     <title>Description</title>
      <methodsynopsis>
       <type>bool</type><methodname>readline_completion_function</methodname>
-      <methodparam choice="opt"><type>string</type><parameter>line</parameter></methodparam>
+      <methodparam choice="opt"><type>callback</type><parameter>line</parameter></methodparam>
      </methodsynopsis>
     <para>
      This function registers a completion function.  You must supply