diff --git a/reference/filesystem/functions/mkdir.xml b/reference/filesystem/functions/mkdir.xml
index cc109423e2..e343679997 100644
--- a/reference/filesystem/functions/mkdir.xml
+++ b/reference/filesystem/functions/mkdir.xml
@@ -167,6 +167,7 @@ if(!mkdir($structure, 0, true))
   &reftitle.seealso;
   <para>
    <simplelist>
+    <member><function>is_dir</function></member>    
     <member><function>rmdir</function></member>
    </simplelist>
   </para>