1 <?xml version="1.0" encoding="utf-8"?>

     2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->

     3 <!-- This component and the accompanying materials are made available under the terms of the License 

     4 "Eclipse Public License v1.0" which accompanies this distribution, 

     5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->

     6 <!-- Initial Contributors:

     7     Nokia Corporation - initial contribution.

     8 Contributors: 

     9 -->

    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-93AB9273-08A5-52CD-AFF7-8B92D72067BF" xml:lang="en"><title>Using

    13 TDes</title><shortdesc>Use TDes for interfaces which take narrow or wide (Unicode) text,

    14 depending on the build variant.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    15 <section id="GUID-3B3CC723-0555-5FCD-8783-F1467BB1191C"><title>Usage in a

    16 function interface</title> <p>An interface which needs to access and modify

    17 either narrow text or wide (Unicode) text, depending on the build variant,

    18 uses a <xref href="GUID-49D4E917-57EA-39AE-8941-144AA8AC2584.dita"><apiname>TDes</apiname></xref> as the argument type. All build independent

    19 concrete descriptors are derived from <codeph>TDes</codeph> which means that

    20 the interface can accept any build independent descriptor.</p> <p>The following

    21 code fragment shows the most common function prototype pattern.</p> <codeblock id="GUID-87812092-5582-51F4-B67B-9A2F503C0A26" xml:space="preserve">void ClassX::foo(TDes&amp; anArg);</codeblock> <p>The

    22 use of <codeph>TDes</codeph> means that data can be accessed and modified

    23 through the descriptor.</p> <p>If the interface is to handle explicit 8 bit

    24 or explicit 16 bit data, regardless of the build variant, then use <xref href="GUID-445B19E5-E2EE-32E2-8D6C-C7D6A9B3C507.dita"><apiname>TDes8</apiname></xref> or <xref href="GUID-C04A9A0C-DBA7-37DA-B744-54FBF3D544CD.dita"><apiname>TDes16</apiname></xref> instead.</p> </section>

    25 </conbody><related-links>

    26 <link>

    27 <desc><xref href="GUID-3D73DD8F-8D23-5D47-A4F7-3673C993EF8F.dita">Using class TDes8</xref></desc>

    28 </link>

    29 <link href="GUID-0B6C97D3-0E2D-5BBE-B8AC-985902715160.dita"><linktext>Using Class

    30 TDes16</linktext></link>

    31 </related-links></concept>