<?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-93AB9273-08A5-52CD-AFF7-8B92D72067BF" xml:lang="en"><title>Using TDes</title><shortdesc>Use TDes for interfaces which take narrow or wide (Unicode)

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

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

in a function interface</title> <p>An interface which needs to access

and modify either narrow text or wide (Unicode) text, depending on

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

type. All build independent concrete descriptors are derived from <codeph>TDes</codeph> which means that the interface can accept any build

independent descriptor.</p> <p>The following 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 use of <codeph>TDes</codeph> means that data can be accessed

and modified through the descriptor.</p> <p>If the interface is to

handle explicit 8 bit 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>

</conbody><related-links>

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

<linktext>Using Class TDes16</linktext></link>

<link href="GUID-3D73DD8F-8D23-5D47-A4F7-3673C993EF8F.dita"><linktext>Using

class TDes8</linktext></link>