Symbian3/Examples/guid-6013a680-57f9-415b-8851-c4fa63356636/_error_on_fail_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/MemMan/Cleanup/ErrorOnFail/ErrorOnFail.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">// Example shows attempt to construct an object and return an</span>
<a name="l00015"></a>00015 <span class="comment">// appropriate error code on failure.</span>
<a name="l00016"></a>00016 <span class="comment">// NOTE: the structure of this example is different to standard E32 examples</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 <e32cons.h></span>
<a name="l00021"></a>00021
<a name="l00022"></a>00022
<a name="l00023"></a>00023 <span class="comment">//</span>
<a name="l00024"></a>00024 <span class="comment">// Common formats</span>
<a name="l00025"></a>00025 <span class="comment">//</span>
<a name="l00026"></a>00026
<a name="l00027"></a>00027
<a name="l00028"></a>00028 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KCommonFormat1,<span class="stringliteral">"Value of iInt is %d.\n"</span>);
<a name="l00029"></a>00029
<a name="l00030"></a>00030
<a name="l00031"></a>00031 <span class="comment">// All messages written to this</span>
<a name="l00032"></a>00032 LOCAL_D CConsoleBase* console;
<a name="l00033"></a>00033
<a name="l00034"></a>00034 <span class="comment">// Flag which determines whether the doSomething() member function</span>
<a name="l00035"></a>00035 <span class="comment">// of the CExample class should leave when called.</span>
<a name="l00036"></a>00036 LOCAL_D TBool leaveFlag = ETrue;
<a name="l00037"></a>00037
<a name="l00038"></a>00038 <span class="comment">// Parameter for __UHEAP_SETFAIL</span>
<a name="l00039"></a>00039 <span class="comment">// Allocation guaranteed to fail at this number of allocation attempts;</span>
<a name="l00040"></a>00040 <span class="comment">// i.e. if set to n, allocation fails on the nth attempt. </span>
<a name="l00041"></a>00041 <span class="comment">// NB only used in debug mode</span>
<a name="l00042"></a>00042 <span class="preprocessor">#ifdef _DEBUG</span>
<a name="l00043"></a>00043 <span class="preprocessor"></span>LOCAL_D TInt allocFailNumber = 1;
<a name="l00044"></a>00044 <span class="preprocessor">#endif</span>
<a name="l00045"></a>00045 <span class="preprocessor"></span>
<a name="l00046"></a>00046 <span class="comment">// Function prototypes</span>
<a name="l00047"></a>00047 LOCAL_C TInt doExample();
<a name="l00048"></a>00048 LOCAL_C <span class="keywordtype">void</span> callExampleL();
<a name="l00049"></a>00049
<a name="l00050"></a>00050
<a name="l00051"></a>00051
<a name="l00053"></a>00053 <span class="comment">//</span>
<a name="l00054"></a>00054 <span class="comment">// -----> CExample (definition)</span>
<a name="l00055"></a>00055 <span class="comment">//</span>
<a name="l00056"></a>00056 <span class="comment">// The class is used by the example code</span>
<a name="l00057"></a>00057 <span class="comment">//</span>
<a name="l00059"></a>00059 <span class="comment"></span><span class="keyword">class </span>CExample : <span class="keyword">public</span> CBase
<a name="l00060"></a>00060 {
<a name="l00061"></a>00061 <span class="keyword">public</span> :
<a name="l00062"></a>00062 <span class="keywordtype">void</span> DoSomethingL();
<a name="l00063"></a>00063 <span class="keyword">public</span> :
<a name="l00064"></a>00064 TInt iInt;
<a name="l00065"></a>00065 };
<a name="l00066"></a>00066
<a name="l00067"></a>00067
<a name="l00069"></a>00069 <span class="comment">//</span>
<a name="l00070"></a>00070 <span class="comment">// -----> CExample (implementation)</span>
<a name="l00071"></a>00071 <span class="comment">//</span>
<a name="l00073"></a>00073 <span class="comment"></span><span class="keywordtype">void</span> CExample::DoSomethingL()
<a name="l00074"></a>00074 {
<a name="l00075"></a>00075 <span class="comment">// Leave if the global flag is set</span>
<a name="l00076"></a>00076 <span class="keywordflow">if</span> (leaveFlag)
<a name="l00077"></a>00077 {
<a name="l00078"></a>00078 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KMsgLeaving,<span class="stringliteral">"DoSomethingL leaving.\n"</span>);
<a name="l00079"></a>00079 console->Printf(KMsgLeaving);
<a name="l00080"></a>00080 User::Leave(KErrGeneral);
<a name="l00081"></a>00081 }
<a name="l00082"></a>00082 console->Printf(KCommonFormat1,iInt);
<a name="l00083"></a>00083 }
<a name="l00084"></a>00084
<a name="l00086"></a>00086 <span class="comment">//</span>
<a name="l00087"></a>00087 <span class="comment">// Main function called by E32</span>
<a name="l00088"></a>00088 <span class="comment">//</span>
<a name="l00090"></a>00090 <span class="comment"></span>GLDEF_C TInt E32Main()
<a name="l00091"></a>00091 {
<a name="l00092"></a>00092 <span class="comment">// Get cleanup stack</span>
<a name="l00093"></a>00093 CTrapCleanup* cleanup=CTrapCleanup::New();
<a name="l00094"></a>00094
<a name="l00095"></a>00095 <span class="comment">// Some more initialization, then do the example</span>
<a name="l00096"></a>00096 TRAPD(error,callExampleL());
<a name="l00097"></a>00097
<a name="l00098"></a>00098 <span class="comment">// callExampleL() should never leave.</span>
<a name="l00099"></a>00099 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KMsgPanicEpoc32ex,<span class="stringliteral">"EPOC32EX"</span>);
<a name="l00100"></a>00100 __ASSERT_ALWAYS(!error,User::Panic(KMsgPanicEpoc32ex,error));
<a name="l00101"></a>00101
<a name="l00102"></a>00102 <span class="comment">// destroy the cleanup stack</span>
<a name="l00103"></a>00103 <span class="keyword">delete</span> cleanup;
<a name="l00104"></a>00104
<a name="l00105"></a>00105 <span class="comment">// return</span>
<a name="l00106"></a>00106 <span class="keywordflow">return</span> 0;
<a name="l00107"></a>00107 }
<a name="l00108"></a>00108
<a name="l00109"></a>00109
<a name="l00111"></a>00111 <span class="comment">//</span>
<a name="l00112"></a>00112 <span class="comment">//</span>
<a name="l00113"></a>00113 <span class="comment">//</span>
<a name="l00115"></a>00115 <span class="comment"></span>LOCAL_C <span class="keywordtype">void</span> callExampleL()
<a name="l00116"></a>00116 {
<a name="l00117"></a>00117 <span class="comment">// Initialize and call the example code under cleanup stack</span>
<a name="l00118"></a>00118 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KMsgExampleCode,<span class="stringliteral">"Symbian platform Example Code"</span>);
<a name="l00119"></a>00119 console = Console::NewL(KMsgExampleCode,TSize(KConsFullScreen,KConsFullScreen));
<a name="l00120"></a>00120 <span class="comment">// Put console onto the cleanup stack</span>
<a name="l00121"></a>00121 CleanupStack::PushL(console);
<a name="l00122"></a>00122
<a name="l00123"></a>00123 <span class="comment">// Perform the example function</span>
<a name="l00124"></a>00124 TInt retVal;
<a name="l00125"></a>00125 retVal = doExample();
<a name="l00126"></a>00126
<a name="l00127"></a>00127 <span class="comment">// Show the value returned from the example</span>
<a name="l00128"></a>00128 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KFormat2,<span class="stringliteral">"Return code=%d.\n"</span>);
<a name="l00129"></a>00129 console->Printf(KFormat2, retVal);
<a name="l00130"></a>00130 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KMsgPressAnyKey,<span class="stringliteral">" [press any key]"</span>);
<a name="l00131"></a>00131 console->Printf(KMsgPressAnyKey);
<a name="l00132"></a>00132 console->Getch();
<a name="l00133"></a>00133
<a name="l00134"></a>00134 <span class="comment">// Remove the console object from the cleanupstack</span>
<a name="l00135"></a>00135 <span class="comment">// and destroy it </span>
<a name="l00136"></a>00136 CleanupStack::PopAndDestroy();
<a name="l00137"></a>00137 }
<a name="l00138"></a>00138
<a name="l00139"></a>00139
<a name="l00141"></a>00141 <span class="comment">//</span>
<a name="l00142"></a>00142 <span class="comment">// Do the example</span>
<a name="l00143"></a>00143 <span class="comment">//</span>
<a name="l00145"></a>00145 <span class="comment"></span>TInt doExample()
<a name="l00146"></a>00146 {
<a name="l00147"></a>00147 <span class="comment">// Memory alloc fails on the 'allocFailNumber' attempt.</span>
<a name="l00148"></a>00148 __UHEAP_SETFAIL(RHeap::EDeterministic,allocFailNumber);
<a name="l00149"></a>00149 <span class="comment">// Allocate and test</span>
<a name="l00150"></a>00150 CExample* myExample = <span class="keyword">new</span> CExample;
<a name="l00151"></a>00151 <span class="keywordflow">if</span> (!myExample) <span class="keywordflow">return</span>(KErrNoMemory);
<a name="l00152"></a>00152 <span class="comment">// Do something with the CExample object</span>
<a name="l00153"></a>00153 myExample->iInt = 5;
<a name="l00154"></a>00154 <span class="comment">//</span>
<a name="l00155"></a>00155 console->Printf(KCommonFormat1,myExample->iInt);
<a name="l00156"></a>00156 <span class="comment">// Delete the CExample object</span>
<a name="l00157"></a>00157 <span class="keyword">delete</span> myExample;
<a name="l00158"></a>00158 <span class="comment">// Completed OK</span>
<a name="l00159"></a>00159 <span class="keywordflow">return</span> KErrNone;
<a name="l00160"></a>00160 }
<a name="l00161"></a>00161
<a name="l00162"></a>00162
<a name="l00163"></a>00163
<a name="l00164"></a>00164
<a name="l00165"></a>00165
<a name="l00166"></a>00166
<a name="l00167"></a>00167
<a name="l00168"></a>00168
</pre></div></div>
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