diff --git a/reference/filesystem/functions/mkdir.xml b/reference/filesystem/functions/mkdir.xml
index b7bd4629b6..c1a7638d2f 100644
--- a/reference/filesystem/functions/mkdir.xml
+++ b/reference/filesystem/functions/mkdir.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.3 $ -->
+<!-- $Revision: 1.4 $ -->
 <!-- splitted from ./en/functions/filesystem.xml, last change in rev 1.39 -->
   <refentry id="function.mkdir">
    <refnamediv>
@@ -11,7 +11,7 @@
      <methodsynopsis>
       <type>int</type><methodname>mkdir</methodname>
       <methodparam><type>string</type><parameter>pathname</parameter></methodparam>
-      <methodparam>[<type>int</type><parameter>mode</parameter>]</methodparam>
+      <methodparam choice="opt"><type>int</type><parameter>mode</parameter></methodparam>
      </methodsynopsis>
     <para>
      Attempts to create the directory specified by pathname.