--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-E189B0C0-AAB5-5472-996B-91043DE0B6D4.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-E189B0C0-AAB5-5472-996B-91043DE0B6D4" xml:lang="en"><title>Package
+Buffers Overview</title><shortdesc>Allows any value type (a T class) to be encapsulated as a descriptor,
+for the purpose of inter-thread data transfer.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<section id="GUID-D6ADB133-EB0D-41C5-B513-152ED052BA9F"><title>Architectural relationships</title> <p>The Client/Server API
+expects data that is to be passed between threads to be encapsulated in a
+descriptor. Package buffers provide a generic way for the thread providing
+the data to do this. The thread receiving the data extracts the original data
+from the package.</p> <p>APIs with client/server architectures, such as telephony
+and Messaging, define specialised package buffer types that encapsulate the
+particular data types that they require to pass between threads.</p> </section>
+<section id="GUID-545604B3-1A3A-4236-AB40-F15E19D40487"><title>Description</title> <p>The API has two key concepts: package
+buffer descriptor, and package pointer descriptor. </p> </section>
+<section id="GUID-5B34C59B-3D61-48E9-9939-0259E1EC9A64"><title>Package buffer descriptor</title> <p>The package buffer descriptor
+creates a new instance of the type to encapsulate and stores it within the
+descriptor. The interface allows a reference to the encapsulated object to
+be obtained, so that it can be accessed and modified.</p> <p>The package buffer
+descriptor interface is provided by <xref href="GUID-C7A094BD-846F-3ED2-8CCE-C0743DB3712A.dita"><apiname>TPckgBuf</apiname></xref>.</p></section>
+<section id="GUID-B12499C9-B385-43CF-8342-06B34150BE67"><title>Package pointer descriptor</title> <p>The package pointer
+descriptor refers to an already existing object. It is otherwise used in a
+similar way to the package buffer descriptor.</p> <p>The package pointer descriptor
+interface is provided by <xref href="GUID-36B29964-420D-38D0-AF08-4DA70BED8B6E.dita"><apiname>TPckgC</apiname></xref> for const objects, and <xref href="GUID-4DFB8E64-81FF-3D3B-9694-CE51B11DA69A.dita"><apiname>TPckg</apiname></xref> for
+non-const objects. </p> </section>
+</conbody><related-links>
+<link>
+<desc><xref href="GUID-D0D27AEA-FDDB-5F6F-94F6-ADDF5910DC47.dita">Client/Server
+Overview</xref></desc>
+</link>
+<link href="GUID-11EEFB3D-0414-5BEB-9D78-56A4B9154008.dita"><linktext>Using Descriptors</linktext>
+</link>
+</related-links></concept>
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