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  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>
<desc><xref href="GUID-3D73DD8F-8D23-5D47-A4F7-3673C993EF8F.dita">Using class TDes8</xref></desc>
</link>
<link href="GUID-0B6C97D3-0E2D-5BBE-B8AC-985902715160.dita"><linktext>Using Class
TDes16</linktext></link>
</related-links></concept>