diff --git a/functions/var.xml b/functions/var.xml
index a5218dab34..b02f8dc792 100644
--- a/functions/var.xml
+++ b/functions/var.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.86 $ -->
+<!-- $Revision: 1.87 $ -->
  <reference id="ref.variables">
   <title>Variable Functions</title>
   <titleabbrev>Variables</titleabbrev>
@@ -1538,6 +1538,30 @@ echo $v;
    </refsect1>
   </refentry>
 
+  <refentry id='function.is-callable'>
+   <refnamediv>
+    <refname>is_callable</refname>
+    <refpurpose>
+     Find out whether the argument is a valid callable construct
+    </refpurpose>
+   </refnamediv>
+   <refsect1>
+    <title>Description</title>
+    <funcsynopsis>
+     <funcprototype>
+      <funcdef>bool <function>is_callable</function></funcdef>
+      <paramdef>mixed <parameter>var</parameter></paramdef>
+      <paramdef>bool <parameter><optional>syntax_only</optional></parameter></paramdef>
+      <paramdef>string <parameter><optional>callable_name</optional></parameter></paramdef>
+     </funcprototype>
+    </funcsynopsis>
+    <para>
+     &warn.undocumented.func;
+    </para>
+   </refsect1>
+  </refentry>
+  
+
  </reference>
 
 <!-- Keep this comment at the end of the file