--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-59BBEA98-6501-5415-A4B5-3AE8E33957D3.dita	Wed Mar 31 11:11:55 2010 +0100
@@ -0,0 +1,34 @@
+<?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-59BBEA98-6501-5415-A4B5-3AE8E33957D3" xml:lang="en"><title>Server
+services</title><shortdesc>Describes asynchronous services provided by the client-server framework.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>The majority of Symbian platform asynchronous services are provided by
+servers written in accordance with the Symbian platform client-server framework.
+A server is a thread running in user mode, which services requests from client
+threads also running in user mode. An example of asynchronous service provided
+by a server is the <codeph>EventReady(TRequestStatus* aStat)</codeph> function
+provided by the <codeph>RWsSession</codeph> class — the client API to
+the window server. This function requests an event from the window server,
+which the user program can extract and analyse using other <codeph>RWsSession</codeph> functions.</p>
+<p>As with services provided by the kernel, server-provided services are presented
+to clients through a client API, typically an <codeph>R</codeph> class such
+as <codeph>RWsSession</codeph>, derived from <codeph>RSessionBase</codeph>.
+When the <codeph>RSessionBase</codeph> is opened, a server-side object is
+created and the client’s thread id is noted. Request functions are converted
+into an inter-thread message which encapsulates all the parameters. When request
+functions complete, the server posts the request status and signals the client
+thread’s request semaphore.</p>
+<p>As with services provided by the kernel, the process of requesting asynchronous
+service from a server, and handling its completion, involves messaging and
+inter-thread communication. Symbian platform provides efficient services to
+support these.</p>
+</conbody></concept>
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