Symbian3/Examples/guid-6013a680-57f9-415b-8851-c4fa63356636/helloworldexeexample_8c_source.html
Week 32 contribution of PDK documentation content. See release notes for details. Fixes bug Bug 3582
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<h1>examples/PIPS/HelloWorldExample/src/helloworldexeexample/helloworldexeexample.c</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// helloworldexeexample.c</span>
<a name="l00002"></a>00002 <span class="comment">//</span>
<a name="l00003"></a>00003 <span class="comment">// Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).</span>
<a name="l00004"></a>00004 <span class="comment">// All rights reserved.</span>
<a name="l00005"></a>00005 <span class="comment">// This component and the accompanying materials are made available</span>
<a name="l00006"></a>00006 <span class="comment">// under the terms of "Eclipse Public License v1.0"</span>
<a name="l00007"></a>00007 <span class="comment">// which accompanies this distribution, and is available</span>
<a name="l00008"></a>00008 <span class="comment">// at the URL "http://www.eclipse.org/legal/epl-v10.html".</span>
<a name="l00009"></a>00009 <span class="comment">//</span>
<a name="l00010"></a>00010 <span class="comment">// Initial Contributors:</span>
<a name="l00011"></a>00011 <span class="comment">// Nokia Corporation - initial contribution.</span>
<a name="l00012"></a>00012 <span class="comment">//</span>
<a name="l00013"></a>00013 <span class="comment">// Contributors:</span>
<a name="l00014"></a>00014 <span class="comment">//</span>
<a name="l00015"></a>00015 <span class="comment">// Description:</span>
<a name="l00016"></a>00016 <span class="comment">//</span>
<a name="l00017"></a>00017
<a name="l00018"></a>00018
<a name="l00019"></a>00019 <span class="comment">/* This example is a simple PIPS STDEXE application. It loads the DLL and calls its exported function. </span>
<a name="l00020"></a>00020 <span class="comment">The application implements the dynamic lookup by name mechanism of the exported function using the libdl APIs.</span>
<a name="l00021"></a>00021 <span class="comment">*/</span>
<a name="l00022"></a>00022
<a name="l00023"></a>00023 <span class="comment">// Include files.</span>
<a name="l00024"></a>00024 <span class="preprocessor">#include <stdio.h></span>
<a name="l00025"></a>00025 <span class="preprocessor">#include <dlfcn.h></span>
<a name="l00026"></a>00026 <span class="preprocessor">#include <stdlib.h></span>
<a name="l00027"></a>00027
<a name="l00031"></a>00031 <span class="keywordtype">void</span> PressAKey()
<a name="l00032"></a>00032 {
<a name="l00033"></a>00033 fflush(stdout);
<a name="l00034"></a>00034 getchar();
<a name="l00035"></a>00035 }
<a name="l00040"></a>00040 <span class="keywordtype">int</span> DisplayErrorMessage()
<a name="l00041"></a>00041 {
<a name="l00042"></a>00042 <span class="comment">// Obtain the last error occurred using the libdl API, dlerror().</span>
<a name="l00043"></a>00043 <span class="keyword">const</span> <span class="keywordtype">char</span> *q = dlerror();
<a name="l00044"></a>00044
<a name="l00045"></a>00045 <span class="comment">// Prints the error message.</span>
<a name="l00046"></a>00046 printf(<span class="stringliteral">"%s"</span>,q);
<a name="l00047"></a>00047 PressAKey();
<a name="l00048"></a>00048
<a name="l00049"></a>00049 <span class="comment">// returns the failure code.</span>
<a name="l00050"></a>00050 <span class="keywordflow">return</span> EXIT_FAILURE;
<a name="l00051"></a>00051 }
<a name="l00052"></a>00052
<a name="l00053"></a>00053 <span class="keywordtype">int</span> <a class="code" href="redirectprintf_8c.html#a840291bc02cba5474a4cb46a9b9566fe">main</a>()
<a name="l00054"></a>00054 {
<a name="l00055"></a>00055 <span class="keywordtype">int</span> result;
<a name="l00056"></a>00056
<a name="l00057"></a>00057 <span class="comment">// Handle to load the dynamic library.</span>
<a name="l00058"></a>00058 <span class="keywordtype">void</span>* handleToDll;
<a name="l00059"></a>00059
<a name="l00060"></a>00060 <span class="keyword">typedef</span> void (*PrintHelloWorldFunction)(void);
<a name="l00061"></a>00061 PrintHelloWorldFunction PrintHelloWorld;
<a name="l00062"></a>00062
<a name="l00063"></a>00063 <span class="comment">// Contains name of the DLL file.</span>
<a name="l00064"></a>00064 <span class="keywordtype">char</span> dllFileName[] = <span class="stringliteral">"helloworlddllexample.dll"</span>;
<a name="l00065"></a>00065
<a name="l00071"></a>00071 handleToDll = dlopen(dllFileName, RTLD_LAZY);
<a name="l00072"></a>00072
<a name="l00073"></a>00073 <span class="comment">// Check the descriptor value.If it is null, the error message is printed.</span>
<a name="l00074"></a>00074 <span class="keywordflow">if</span> (!handleToDll)
<a name="l00075"></a>00075 {
<a name="l00076"></a>00076 DisplayErrorMessage();
<a name="l00077"></a>00077 }
<a name="l00078"></a>00078
<a name="l00079"></a>00079 <span class="comment">// Print the message to start the example application.</span>
<a name="l00080"></a>00080 printf(<span class="stringliteral">" Press enter key to step through the example application\n"</span>);
<a name="l00081"></a>00081 PressAKey();
<a name="l00082"></a>00082
<a name="l00088"></a>00088 PrintHelloWorld = (PrintHelloWorldFunction)dlsym(handleToDll, <span class="stringliteral">"PrintHelloWorld"</span>);
<a name="l00089"></a>00089
<a name="l00090"></a>00090 <span class="comment">// Check the symbol address value. If this is null, the error message is printed.</span>
<a name="l00091"></a>00091 <span class="keywordflow">if</span>(!PrintHelloWorld)
<a name="l00092"></a>00092 {
<a name="l00093"></a>00093 DisplayErrorMessage();
<a name="l00094"></a>00094 }
<a name="l00095"></a>00095
<a name="l00096"></a>00096 <span class="comment">// Call the loaded DLL's exported function.</span>
<a name="l00097"></a>00097 PrintHelloWorld();
<a name="l00098"></a>00098
<a name="l00105"></a>00105 result= dlclose(handleToDll);
<a name="l00106"></a>00106
<a name="l00107"></a>00107 <span class="comment">// Check the return value. If this is -1, the error message is printed.</span>
<a name="l00108"></a>00108 <span class="keywordflow">if</span>(result == -1)
<a name="l00109"></a>00109 {
<a name="l00110"></a>00110 DisplayErrorMessage();
<a name="l00111"></a>00111 }
<a name="l00112"></a>00112
<a name="l00113"></a>00113 <span class="comment">// Print the message to exit from the example application.</span>
<a name="l00114"></a>00114 printf(<span class="stringliteral">" Press enter key to exit from the example application"</span>);
<a name="l00115"></a>00115 PressAKey();
<a name="l00116"></a>00116
<a name="l00117"></a>00117 <span class="comment">// returns the success code.</span>
<a name="l00118"></a>00118 <span class="keywordflow">return</span> EXIT_SUCCESS;
<a name="l00119"></a>00119 }
<a name="l00120"></a>00120
<a name="l00121"></a>00121
<a name="l00122"></a>00122
</pre></div></div>
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