--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/PDK/Source/GUID-DCB8CA27-F64F-4B78-831D-F88B1AD7E38B.dita	Fri Jan 22 18:26:19 2010 +0000
@@ -0,0 +1,60 @@
+<?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 task
+  PUBLIC "-//OASIS//DTD DITA Task//EN" "task.dtd">
+<task id="GUID-DCB8CA27-F64F-4B78-831D-F88B1AD7E38B" xml:lang="en"><title>Create
+the client class</title><prolog><metadata><keywords/></metadata></prolog><taskbody>
+<context>       <p>Create the client-side service support class, derived from <codeph>REikAppServiceBase</codeph>, <codeph>RApaAppServiceBase</codeph>, or a suitable System-GUI specialization of this class. This will have the
+following responsibilities:</p> <ul>
+<li><p>Implementing the client API </p></li>
+<li><p>Organizing calls to and from the server over IPC</p></li>
+<li><p>Any necessary security checks on the server. For example, restricting
+the data sent to a server having particular capabilities.</p></li>
+<li><p>Parameter checking from the server. Parameters returned from the server
+application must be checked to ensure that they are valid.</p></li>
+<li><p>Time-out support for IPC calls to the server.</p></li>
+</ul><p>The reason for these checks is that the client cannot be sure that
+the server application is using the appropriate server-side service support
+classes and may instead be trying to weaken the system by implementing the
+IPC handling itself.</p><p>This example shows the client interface for a chat
+service implemented in two parts. The active object class <codeph>CChatter</codeph> is
+the main client interface. It uses a class <codeph>RInterAppChat</codeph>,
+derived from <codeph>REikAppServiceBase</codeph>, which handles the client-side
+IPC for the chat service. </p><codeblock xml:space="preserve">class RInterAppChat : public REikAppServiceBase
+    {
+    public:
+        TInt Send(const TDesC&amp; aMessage);
+        void Receive(TRequestStatus&amp; aStatus, TDes&amp; aMessage);
+        void CancelReceive();
+    private:
+        TUid ServiceUid() const;
+    };
+class MChatterReceiver
+    {
+    public:
+        virtual void Receive(const TDesC&amp;) = 0;
+    };
+class CChatter : public CActive
+    {
+    public:
+        CChatter(MChatterReceiver&amp; aReceiver);
+        ~CChatter();
+        void ConstructL(TUid aAppUid);
+        void SendL(const TDesC&amp; aMsg);
+    private:
+        void Queue();
+        void RunL();
+        void DoCancel();
+    public:
+        RInterAppChat iSub;
+        TBuf&lt;KMaxMyMessage&gt; iBuf;
+        MChatterReceiver&amp; iReceiver;
+    };</codeblock></context>
+</taskbody></task>
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