--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-C85B4EA2-0184-52AF-B097-152E4A023CEF.dita	Thu Jan 21 18:18:20 2010 +0000
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+<?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-C85B4EA2-0184-52AF-B097-152E4A023CEF" xml:lang="en"><title>Abstract
+base descriptor classes</title><shortdesc>Describes the modifiable descriptor class and the non-modifiable
+descriptor class.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>The concrete descriptor classes are all derived from a set of base classes.
+The base classes are abstract and implement nearly most of the behaviour of
+descriptors. They are:</p>
+<ul>
+<li id="GUID-0942F246-8BB5-50DB-8314-AA4B1DD1B8C0"><p>The abstract non-modifiable
+descriptor</p> </li>
+<li id="GUID-1750CF5B-E6F3-57E5-A107-B17DA0481E22"><p>The abstract modifiable
+descriptor</p> </li>
+</ul>
+<section id="GUID-136970EE-DFB5-469F-9597-1105AA05947E"><title>The abstract non-modifiable descriptor class</title> <p>The
+class has a data member containing the length of the data represented by the
+serived concrete descriptor. It also provides the set of functions through
+which data can be accessed but not modified.</p> <p>This class is supplied
+in two variants:</p> <ul>
+<li id="GUID-669B11F1-84DA-5064-88B8-5D3F603114F6"><p>the 16 bit variant,
+a <codeph>TDesC16</codeph>, to handle Unicode strings.</p> </li>
+<li id="GUID-A9F1113E-0736-570D-BF57-B060817549C8"><p>the 8 bit variant, a <codeph>TDesC8</codeph>,
+to handle non-Unicode strings and binary data.</p> </li>
+</ul> <p>There is also a build independent type, <codeph>TDesC</codeph>. This
+is the type which is most commonly used in program code; the appropriate variant
+is selected at build time.</p> <p>An explicit 8 bit variant is chosen when
+handling binary data. The explicit 16 bit variant is rarely used.</p> </section>
+<section id="GUID-DA165923-2587-4F77-AEAF-FA012B7EAC24"><title>The abstract modifiable descriptor class</title> <p>The class
+has a data member containing the maximum length of data that the descriptor
+is capable of representing. It also provides the set of functions through
+which data can be modified.</p> <p>This class is supplied in two variants:</p> <ul>
+<li id="GUID-3F876EFE-1E91-5834-914A-45478D70B0A7"><p>the 16 bit variant,
+a <codeph>TDes16</codeph>, to handle Unicode strings.</p> </li>
+<li id="GUID-1F1F3894-3CD0-5DEB-AA75-8259CC86BF58"><p>the 8 bit variant, a <codeph>TDes8</codeph>,
+to handle non-Unicode strings and binary data.</p> </li>
+</ul> <p>There is also a build independent type, <codeph>TDes</codeph>. This
+is the type which is most commonly used in program code; the appropriate variant
+is selected at build time.</p> <p>An explicit 8 bit variant is chosen when
+handling binary data. The explicit 16 bit variant is rarely used.</p> </section>
+</conbody></concept>
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