diff --git a/functions/sem.xml b/functions/sem.xml
index 4c323d1685..393a2c6ca6 100644
--- a/functions/sem.xml
+++ b/functions/sem.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.17 $ -->
+<!-- $Revision: 1.18 $ -->
  <reference id="ref.sem">
   <title>Semaphore and Shared Memory Functions</title>
   <titleabbrev>Semaphore</titleabbrev>
@@ -387,6 +387,28 @@
    </refsect1>
   </refentry>
 
+  <refentry id='function.ftok'>
+   <refnamediv>
+    <refname>ftok</refname>
+    <refpurpose>
+     Convert a pathname and a project identifier to a System V IPC key
+    </refpurpose>
+   </refnamediv>
+   <refsect1>
+    <title>Description</title>
+    <funcsynopsis>
+     <funcprototype>
+      <funcdef>int <function>ftok</function></funcdef>
+      <paramdef>string <parameter>pathname</parameter></paramdef>
+      <paramdef>string <parameter>proj</parameter></paramdef>
+     </funcprototype>
+    </funcsynopsis>
+    <para>
+     &warn.undocumented.func;
+    </para>
+   </refsect1>
+  </refentry>
+
 </reference>
 
 <!-- Keep this comment at the end of the file