Symbian3/Examples/guid-6013a680-57f9-415b-8851-c4fa63356636/_wait_loop_8cpp_source.html
Week 32 contribution of PDK documentation content. See release notes for details. Fixes bug Bug 3582
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<h1>examples/Base/IPC/Async/WaitLoop/WaitLoop.cpp</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// Copyright (c) 2000-2009 Nokia Corporation and/or its subsidiary(-ies).</span>
<a name="l00002"></a>00002 <span class="comment">// All rights reserved.</span>
<a name="l00003"></a>00003 <span class="comment">// This component and the accompanying materials are made available</span>
<a name="l00004"></a>00004 <span class="comment">// under the terms of "Eclipse Public License v1.0"</span>
<a name="l00005"></a>00005 <span class="comment">// which accompanies this distribution, and is available</span>
<a name="l00006"></a>00006 <span class="comment">// at the URL "http://www.eclipse.org/legal/epl-v10.html".</span>
<a name="l00007"></a>00007 <span class="comment">//</span>
<a name="l00008"></a>00008 <span class="comment">// Initial Contributors:</span>
<a name="l00009"></a>00009 <span class="comment">// Nokia Corporation - initial contribution.</span>
<a name="l00010"></a>00010 <span class="comment">//</span>
<a name="l00011"></a>00011 <span class="comment">// Contributors:</span>
<a name="l00012"></a>00012 <span class="comment">//</span>
<a name="l00013"></a>00013 <span class="comment">// Description:</span>
<a name="l00014"></a>00014 <span class="comment">// Show asynchronous programming (without active objects)</span>
<a name="l00015"></a>00015 <span class="comment">// Example shows how a wait loop can be used to identify how a</span>
<a name="l00016"></a>00016 <span class="comment">// request completed and service its completion</span>
<a name="l00017"></a>00017 <span class="comment">//</span>
<a name="l00018"></a>00018
<a name="l00019"></a>00019
<a name="l00020"></a>00020 <span class="preprocessor">#include "CommonFramework.h"</span>
<a name="l00021"></a>00021 <span class="preprocessor">#include <e32math.h></span>
<a name="l00022"></a>00022
<a name="l00023"></a>00023 <span class="comment">//</span>
<a name="l00024"></a>00024 <span class="comment">// utility functions</span>
<a name="l00025"></a>00025 <span class="comment">//</span>
<a name="l00026"></a>00026
<a name="l00027"></a>00027 LOCAL_D TInt64 smallRandSeed;
<a name="l00028"></a>00028
<a name="l00029"></a>00029 LOCAL_C TInt smallRand()
<a name="l00030"></a>00030 {
<a name="l00031"></a>00031 <span class="comment">// produce small random numbers in range 0..9</span>
<a name="l00032"></a>00032 TInt bigResult=Math::Rand(smallRandSeed);<span class="comment">// result uses full 32-bit range</span>
<a name="l00033"></a>00033 <span class="keywordflow">return</span> bigResult % 10; <span class="comment">// return result mod 10</span>
<a name="l00034"></a>00034 }
<a name="l00035"></a>00035
<a name="l00036"></a>00036 LOCAL_C <span class="keywordtype">void</span> sleep(TInt aTenths)
<a name="l00037"></a>00037 {
<a name="l00038"></a>00038 <span class="comment">// sleep for an interval measured in tenths of a second</span>
<a name="l00039"></a>00039 User::After(aTenths*100000); <span class="comment">// just let the User function do it for us</span>
<a name="l00040"></a>00040 }
<a name="l00041"></a>00041
<a name="l00042"></a>00042
<a name="l00043"></a>00043 <span class="comment">// Do the example</span>
<a name="l00044"></a>00044 LOCAL_C <span class="keywordtype">void</span> doExampleL()
<a name="l00045"></a>00045 {
<a name="l00046"></a>00046 <span class="comment">// create and initialize heartbeat timer</span>
<a name="l00047"></a>00047 RTimer heartbeat; <span class="comment">// heartbeat timer</span>
<a name="l00048"></a>00048 TRequestStatus heartbeatStatus; <span class="comment">// request status associated with it</span>
<a name="l00049"></a>00049 heartbeat.CreateLocal(); <span class="comment">// always created for this thread</span>
<a name="l00050"></a>00050
<a name="l00051"></a>00051 <span class="comment">// issue first heartbeat request</span>
<a name="l00052"></a>00052 heartbeat.After(heartbeatStatus,1000000); <span class="comment">// request completion</span>
<a name="l00053"></a>00053 <span class="comment">// after 1 second</span>
<a name="l00054"></a>00054 TInt heartbeatTick=0; <span class="comment">// counts heartbeat ticks</span>
<a name="l00055"></a>00055
<a name="l00056"></a>00056 <span class="comment">// wait loop</span>
<a name="l00057"></a>00057 <span class="keywordflow">for</span> (;;)
<a name="l00058"></a>00058 {
<a name="l00059"></a>00059 <span class="comment">// wait for any request</span>
<a name="l00060"></a>00060 User::WaitForAnyRequest();
<a name="l00061"></a>00061 <span class="comment">// find out which request completed, and handle it</span>
<a name="l00062"></a>00062 <span class="keywordflow">if</span> (heartbeatStatus!=KRequestPending)
<a name="l00063"></a>00063 {
<a name="l00064"></a>00064 <span class="comment">// heartbeat completed so service request</span>
<a name="l00065"></a>00065 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KMsgServicing,<span class="stringliteral">"Servicing heartbeat tick %d ...\n"</span>);
<a name="l00066"></a>00066 console->Printf(KMsgServicing,heartbeatTick);
<a name="l00067"></a>00067 <span class="comment">// take some time over it</span>
<a name="l00068"></a>00068 sleep(smallRand());
<a name="l00069"></a>00069 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KMsgServiced,<span class="stringliteral">"... heartbeat tick %d serviced\n"</span>);
<a name="l00070"></a>00070 console->Printf(KMsgServiced,heartbeatTick);
<a name="l00071"></a>00071 <span class="comment">// test whether processing should finish</span>
<a name="l00072"></a>00072 <span class="keywordflow">if</span> (heartbeatTick >= 10)
<a name="l00073"></a>00073 {
<a name="l00074"></a>00074 <span class="comment">// 10 heart-beats: processing finished</span>
<a name="l00075"></a>00075 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KMsgFinishing,<span class="stringliteral">"Finishing\n"</span>);
<a name="l00076"></a>00076 console->Printf(KMsgFinishing);
<a name="l00077"></a>00077 <span class="comment">// finish wait loop</span>
<a name="l00078"></a>00078 <span class="keywordflow">break</span>;
<a name="l00079"></a>00079 }
<a name="l00080"></a>00080 <span class="comment">// re-issue request</span>
<a name="l00081"></a>00081 heartbeatTick++; <span class="comment">// increment tick</span>
<a name="l00082"></a>00082 <span class="comment">// counter</span>
<a name="l00083"></a>00083 heartbeat.After(heartbeatStatus,1000000); <span class="comment">// request completion</span>
<a name="l00084"></a>00084 <span class="comment">// after another second</span>
<a name="l00085"></a>00085 }
<a name="l00086"></a>00086 <span class="keywordflow">else</span>
<a name="l00087"></a>00087 {
<a name="l00088"></a>00088 <span class="comment">// stray signal</span>
<a name="l00089"></a>00089 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KMsgStraySignal,<span class="stringliteral">"Stray signal\n"</span>);
<a name="l00090"></a>00090 User::Panic(KMsgStraySignal, 1); <span class="comment">// panic!</span>
<a name="l00091"></a>00091 }
<a name="l00092"></a>00092 }
<a name="l00093"></a>00093
<a name="l00094"></a>00094 <span class="comment">// close timer</span>
<a name="l00095"></a>00095 heartbeat.Close(); <span class="comment">// close timer</span>
<a name="l00096"></a>00096 }
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