--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-6163197B-7983-5FB7-9B92-02E490A900FB.dita	Thu Jan 21 18:18:20 2010 +0000
@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-6163197B-7983-5FB7-9B92-02E490A900FB" xml:lang="en"><title>How to
+construct a header</title><shortdesc>This document describes how to create a header for a doubly linked
+list.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>In order to construct a header, two important pieces of information are
+needed:</p>
+<ul>
+<li id="GUID-2E721D77-E010-5211-BABE-94578AECEEE4"><p>the <i>type</i> of object
+which forms the elements.</p> </li>
+<li id="GUID-71FC8FBF-803F-55BC-AC52-D672B1DA36BA"><p>the <i>offset</i> of
+the link object from the start of the element.</p> </li>
+</ul>
+<p>To create a header for a doubly linked list of <codeph>CMyClass</codeph> elements,
+defined as:</p>
+<codeblock id="GUID-D995F2F7-6A38-5EE3-9210-1302E1662759" xml:space="preserve">class CMyClass : public CBase
+    {
+    ...
+    TDblQueLink iDlink;
+    ...
+    };</codeblock>
+<p>construct a <codeph>TDblQue</codeph> as follows:</p>
+<codeblock id="GUID-D13C33D2-EE7E-5915-92E2-F3EC5C772B4D" xml:space="preserve">TDblQue&lt;CMyClass&gt; queHeader(_FOFF(CMyClass,iDlink));</codeblock>
+<p>The <codeph>TDblQue</codeph> class takes a class template parameter which
+defines the type of object which is to form an element of the list. In this
+example, objects of type <codeph>CMyClass</codeph> form the elements of the
+list.</p>
+<p>The <codeph>_FOFF</codeph> macro (i.e. the "field offset" macro) calculates
+the offset of the component link object within the element. In this example,
+the required value is the offset of the <codeph>iDlink</codeph> data member
+from the start of <codeph>CMyClass</codeph>. </p>
+<fig id="GUID-9C102C34-EFFA-530A-AA1E-C6AE08FDFA37">
+<title/>
+<image href="GUID-29E7942D-A00D-5771-9782-59260965C687_d0e189052_href.png" placement="inline"/>
+</fig>
+</conbody></concept>
\ No newline at end of file