--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-8255A186-C1AC-44DA-844C-1FEA029C73BC.dita	Wed Mar 31 11:11:55 2010 +0100
@@ -0,0 +1,36 @@
+<?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-8255A186-C1AC-44DA-844C-1FEA029C73BC" xml:lang="en"><title>Publish
+and Subscribe</title><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p><i>Publish and Subscribe</i> has replaced System Agent and the usage
+of temporary Shared Data keys.</p>
+<p>Publish and Subscribe allows the setting, retrieving and monitoring
+of system-wide variables and provides a new inter process communication (IPC)
+mechanism for peer to peer communication between threads. Threads may have
+the role of the publisher or of the subscriber, while any thread can define
+the property to be published. The process that defines a property can specify
+access rights for both reading and writing. Rights can be defined in terms
+of either requiring a particular <xref href="GUID-6971B0A2-F79B-4E05-8AF3-BB1FC1932A22.dita">capability</xref>,
+by a process <xref href="GUID-3B6E25F7-C1A8-461F-97F7-421DB559BC98.dita#GUID-3B6E25F7-C1A8-461F-97F7-421DB559BC98/GUID-EEC50FC0-46D5-4ED7-AD95-67430D5EC652">Secure
+Identifier</xref>, or by a process <xref href="GUID-3B6E25F7-C1A8-461F-97F7-421DB559BC98.dita#GUID-3B6E25F7-C1A8-461F-97F7-421DB559BC98/GUID-EEC50FC0-46D5-4ED7-AD95-67430D5EC654">VID</xref>. </p>
+<p>Publish and Subscribe should be considered under any of the following
+conditions:</p>
+<ul>
+<li><p>An event should be sent simultaneously to multiple places
+over the system.</p></li>
+<li><p>Only the last value of the property is significant, not the
+intermediate values.</p></li>
+<li><p>The source of the value is not significant. The value may
+have been set by any publisher with proper rights.</p></li>
+</ul>
+<p>For more information about the use of Publish and Subscribe, see <xref href="GUID-FE910347-7CC1-5241-B443-88AD3F5A96EF.dita">Using Publish and Subscribe</xref>.</p>
+</conbody></concept>
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