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3 <title>TB10.1 Example Applications: examples/PIPS/posixsignals/asyncSignal/src/sigusr1.c Source File</title> |
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8 <h1>examples/PIPS/posixsignals/asyncSignal/src/sigusr1.c</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// sigusr1.c</span> |
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9 <a name="l00002"></a>00002 <span class="comment">//</span> |
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10 <a name="l00003"></a>00003 <span class="comment">// Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).</span> |
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11 <a name="l00004"></a>00004 <span class="comment">// All rights reserved.</span> |
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12 <a name="l00005"></a>00005 <span class="comment">// This component and the accompanying materials are made available</span> |
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13 <a name="l00006"></a>00006 <span class="comment">// under the terms of "Eclipse Public License v1.0"</span> |
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14 <a name="l00007"></a>00007 <span class="comment">// which accompanies this distribution, and is available</span> |
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15 <a name="l00008"></a>00008 <span class="comment">// at the URL "http://www.eclipse.org/legal/epl-v10.html".</span> |
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16 <a name="l00009"></a>00009 <span class="comment">//</span> |
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17 <a name="l00010"></a>00010 <span class="comment">// Initial Contributors:</span> |
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18 <a name="l00011"></a>00011 <span class="comment">// Nokia Corporation - initial contribution.</span> |
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19 <a name="l00012"></a>00012 <span class="comment">//</span> |
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20 <a name="l00013"></a>00013 <span class="comment">// Contributors:</span> |
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21 <a name="l00014"></a>00014 <span class="comment">//</span> |
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22 <a name="l00015"></a>00015 <span class="comment">// Description:This example demonstrates asynchronous signal handling.</span> |
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23 <a name="l00016"></a>00016 <span class="comment">//</span> |
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24 <a name="l00017"></a>00017 |
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25 <a name="l00018"></a>00018 |
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26 <a name="l00019"></a>00019 <span class="preprocessor">#include <stdio.h></span> |
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27 <a name="l00020"></a>00020 <span class="preprocessor">#include <stdlib.h></span> |
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28 <a name="l00021"></a>00021 <span class="preprocessor">#include <signal.h></span> <span class="comment">//The header for signal functionality.</span> |
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29 <a name="l00022"></a>00022 <span class="preprocessor">#include <unistd.h></span> <span class="comment">//The header used for getpid().</span> |
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30 <a name="l00023"></a>00023 <span class="preprocessor">#include <e32def.h></span> |
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31 <a name="l00024"></a>00024 <span class="preprocessor">#include <spawn.h></span> |
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32 <a name="l00025"></a>00025 |
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33 <a name="l00026"></a>00026 <span class="keywordtype">int</span> gch; <span class="comment">// The variable holding a character value, input by the user.</span> |
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34 <a name="l00027"></a>00027 FILE *gfp = NULL; <span class="comment">// The file descriptor variable holding pointer to asyncFile.txt.</span> |
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35 <a name="l00028"></a>00028 pid_t chldProcsID; <span class="comment">// The variable for holding the sigusr2 PID.</span> |
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36 <a name="l00029"></a>00029 <span class="keywordtype">int</span> gVal = TRUE; <span class="comment">// Variable used as a boolean value.</span> |
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37 <a name="l00033"></a>00033 <span class="comment"></span><span class="keywordtype">void</span> SIGUSR1_handler(<span class="keywordtype">int</span> signum) |
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38 <a name="l00034"></a>00034 { |
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39 <a name="l00035"></a>00035 <span class="keywordtype">int</span> ret; |
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40 <a name="l00036"></a>00036 <span class="keyword">const</span> <span class="keywordtype">int</span> delay1 = 1; <span class="comment">//Time delay of 1 sec.</span> |
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41 <a name="l00037"></a>00037 <span class="keywordflow">if</span> (signum == SIGUSR1) |
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42 <a name="l00038"></a>00038 { |
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43 <a name="l00039"></a>00039 gVal = FALSE; |
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44 <a name="l00040"></a>00040 printf(<span class="stringliteral">"\nReceived the SIGUSR1 signal from the sigusr2 process\n"</span>); |
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45 <a name="l00041"></a>00041 printf(<span class="stringliteral">"Starting to read from the file\n"</span>); |
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46 <a name="l00042"></a>00042 <span class="keywordflow">while</span>((gch = fgetc(gfp))!=<span class="charliteral">'\n'</span>) |
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47 <a name="l00043"></a>00043 { |
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48 <a name="l00044"></a>00044 putchar(gch); <span class="comment">//Writing to stdout.</span> |
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49 <a name="l00045"></a>00045 } |
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50 <a name="l00046"></a>00046 printf(<span class="stringliteral">"\n"</span>); |
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51 <a name="l00047"></a>00047 sleep (delay1); |
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52 <a name="l00048"></a>00048 |
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53 <a name="l00049"></a>00049 <span class="comment">//Sending SIGUSR2 signal to sigusr2 process once the file content is written to the console.</span> |
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54 <a name="l00050"></a>00050 printf(<span class="stringliteral">"Reading from the file now completed, sending SIGUSR2 to the sigusr2 process\n"</span>); |
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55 <a name="l00051"></a>00051 |
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56 <a name="l00052"></a>00052 <span class="comment">//Raising SIGUSR2 signal using kill command.</span> |
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57 <a name="l00053"></a>00053 ret = kill(chldProcsID,SIGUSR2); |
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58 <a name="l00054"></a>00054 <span class="keywordflow">if</span>(ret) |
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59 <a name="l00055"></a>00055 { |
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60 <a name="l00056"></a>00056 printf(<span class="stringliteral">"kill() failed to send signal, errno=%d\n"</span>,errno); |
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61 <a name="l00057"></a>00057 } |
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62 <a name="l00058"></a>00058 } |
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63 <a name="l00059"></a>00059 } |
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64 <a name="l00060"></a>00060 |
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65 <a name="l00074"></a>00074 <span class="keywordtype">int</span> main() |
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66 <a name="l00075"></a>00075 { |
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67 <a name="l00076"></a>00076 <span class="keywordtype">int</span> ret; |
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68 <a name="l00077"></a>00077 <span class="keyword">const</span> <span class="keywordtype">int</span> delay = 1; <span class="comment">//Delay of 1 sec provided to wait for signal.</span> |
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69 <a name="l00078"></a>00078 <span class="keyword">const</span> <span class="keywordtype">int</span> size = 50; <span class="comment">//No.of characters allowed in the filename.</span> |
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70 <a name="l00079"></a>00079 <span class="keyword">const</span> <span class="keywordtype">int</span> index = 3; <span class="comment">//No.of elements in the array.</span> |
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71 <a name="l00080"></a>00080 |
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72 <a name="l00081"></a>00081 <span class="keywordtype">char</span> *filename = <span class="stringliteral">"C:\\asyncFile.txt"</span> ; <span class="comment">//Filename of the file that holds names input by the user.</span> |
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73 <a name="l00082"></a>00082 <span class="keywordtype">char</span> *childProcess = <span class="stringliteral">"Z:\\sys\\bin\\sigusr2.exe"</span>; <span class="comment">//Filename of sigusr2 process.</span> |
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74 <a name="l00083"></a>00083 <span class="keywordtype">char</span> **argv = (<span class="keywordtype">char</span>**)malloc(index*<span class="keyword">sizeof</span>(<span class="keywordtype">char</span>*)); <span class="comment">//Variable holding values to be passed to the sigusr2 process.</span> |
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75 <a name="l00084"></a>00084 argv[0] = (<span class="keywordtype">char</span>*)malloc(size*<span class="keyword">sizeof</span>(<span class="keywordtype">char</span>)); |
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76 <a name="l00085"></a>00085 argv[1] = (<span class="keywordtype">char</span>*)malloc(index*<span class="keyword">sizeof</span>(<span class="keywordtype">char</span>)); |
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77 <a name="l00086"></a>00086 argv[2] = NULL; |
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78 <a name="l00087"></a>00087 |
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79 <a name="l00088"></a>00088 |
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80 <a name="l00089"></a>00089 strcpy(argv[0], <span class="stringliteral">"z:\\sys\\bin\\sigusr2.exe"</span>); <span class="comment">//argv[0] holding name of the sigusr2 process.</span> |
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81 <a name="l00090"></a>00090 sprintf(argv[1],<span class="stringliteral">"%d"</span>,getpid()); <span class="comment">//argv[1] holding PID of sigusr1 process.</span> |
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82 <a name="l00091"></a>00091 |
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83 <a name="l00092"></a>00092 <span class="comment">//Setup the custom handler for SIGUSR1.</span> |
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84 <a name="l00093"></a>00093 signal(SIGUSR1,SIGUSR1_handler); |
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85 <a name="l00094"></a>00094 |
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86 <a name="l00095"></a>00095 printf(<span class="stringliteral">"*****************************************************************\n"</span>); |
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87 <a name="l00096"></a>00096 printf(<span class="stringliteral">"* Welcome to the asynchronous signal handling demonstration *\n"</span>); |
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88 <a name="l00097"></a>00097 printf(<span class="stringliteral">"*****************************************************************\n"</span>); |
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89 <a name="l00098"></a>00098 |
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90 <a name="l00099"></a>00099 printf(<span class="stringliteral">"* This example demonstrates asynchronous signal handling using SIGUSR1 and SIGUSR2 signals.\n"</span>); |
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91 <a name="l00100"></a>00100 printf(<span class="stringliteral">"* The example consists of two processes, the sigusr1 process and the sigusr2 process.\n"</span>); |
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92 <a name="l00101"></a>00101 printf(<span class="stringliteral">"* The sigusr1 process handles the SIGUSR1 signal and sends a SIGUSR2 signal to the sigusr2 process.\n"</span>); |
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93 <a name="l00102"></a>00102 printf(<span class="stringliteral">"* The sigusr2 process handles the SIGUSR2 signal and sends a SIGUSR1 signal to the sigusr1 process.\n"</span>); |
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94 <a name="l00103"></a>00103 printf(<span class="stringliteral">"* The sigusr1 process opens a file and writes some text in it.\n"</span>); |
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95 <a name="l00104"></a>00104 printf(<span class="stringliteral">"* The sigusr1 process then spawns the sigusr2 process and waits until SIGUSR1 is received from it.\n"</span>); |
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96 <a name="l00105"></a>00105 printf(<span class="stringliteral">"* Once the sigusr1 process obtains a SIGUSR1 signal, it starts reading from the file and displays its\ncontent on the console.\n"</span>); |
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97 <a name="l00106"></a>00106 printf(<span class="stringliteral">"* When all the file content is written, the sigusr1 process sends a SIGUSR2 signal to the sigusr2 process and prepares to exit.\n"</span>); |
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98 <a name="l00107"></a>00107 printf(<span class="stringliteral">"* On other side the sigusr2 process keeps waiting for the SIGUSR2 signal from the sigusr1 process.\n"</span>); |
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99 <a name="l00108"></a>00108 printf(<span class="stringliteral">"* On reception of the SIGUSR2 signal, the sigusr2 process prepares to exit.\n"</span>); |
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100 <a name="l00109"></a>00109 |
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101 <a name="l00110"></a>00110 printf(<span class="stringliteral">"\nPress the Enter key to continue\n"</span>); |
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102 <a name="l00111"></a>00111 getchar(); |
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103 <a name="l00112"></a>00112 |
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104 <a name="l00113"></a>00113 printf(<span class="stringliteral">"****************** In the sigusr1 process ********************\n"</span>); |
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105 <a name="l00114"></a>00114 |
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106 <a name="l00115"></a>00115 |
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107 <a name="l00116"></a>00116 printf(<span class="stringliteral">"\nOpening a file for read and write\n"</span>); |
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108 <a name="l00117"></a>00117 <span class="keywordflow">if</span>((gfp = fopen(filename,<span class="stringliteral">"w+"</span>))!=NULL) |
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109 <a name="l00118"></a>00118 { |
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110 <a name="l00119"></a>00119 printf(<span class="stringliteral">"Successfully opened the file\n"</span>); |
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111 <a name="l00120"></a>00120 fprintf(gfp, <span class="stringliteral">"%s"</span>, <span class="stringliteral">"An asynchronous signal handling example using the SIGUSR1 and SIGUSR2 signals\n"</span>); |
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112 <a name="l00121"></a>00121 rewind(gfp); |
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113 <a name="l00122"></a>00122 printf(<span class="stringliteral">"Writing to the file completed, preparing to start reading from the file\n"</span>); |
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114 <a name="l00123"></a>00123 |
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115 <a name="l00124"></a>00124 printf(<span class="stringliteral">"Press the Enter key to spawn the sigusr2 process\n"</span>); |
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116 <a name="l00125"></a>00125 getchar(); |
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117 <a name="l00126"></a>00126 |
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118 <a name="l00127"></a>00127 <span class="comment">//Spawning sigusr2 process.</span> |
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119 <a name="l00128"></a>00128 ret = posix_spawn(&chldProcsID,childProcess,NULL,NULL,argv,(<span class="keywordtype">char</span>**)NULL); |
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120 <a name="l00129"></a>00129 <span class="keywordflow">if</span>(ret != 0) |
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121 <a name="l00130"></a>00130 { |
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122 <a name="l00131"></a>00131 printf(<span class="stringliteral">"\n*** failure posix_spawn ***\n"</span>); |
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123 <a name="l00132"></a>00132 <span class="keywordflow">return</span> EXIT_FAILURE; |
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124 <a name="l00133"></a>00133 } |
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125 <a name="l00134"></a>00134 } |
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126 <a name="l00135"></a>00135 |
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127 <a name="l00136"></a>00136 printf(<span class="stringliteral">"Waiting until SIGUSR1 is obtained from the sigusr2 process"</span>); |
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128 <a name="l00137"></a>00137 <span class="keywordflow">while</span>(gVal) |
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129 <a name="l00138"></a>00138 { |
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130 <a name="l00139"></a>00139 printf(<span class="stringliteral">"."</span>); |
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131 <a name="l00140"></a>00140 sleep(delay); |
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132 <a name="l00141"></a>00141 } |
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133 <a name="l00142"></a>00142 |
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134 <a name="l00143"></a>00143 <span class="keywordflow">if</span>(!fclose(gfp)) |
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135 <a name="l00144"></a>00144 { |
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136 <a name="l00145"></a>00145 <span class="keyword">remove</span>(filename); |
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137 <a name="l00146"></a>00146 gfp=NULL; |
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138 <a name="l00147"></a>00147 printf(<span class="stringliteral">"The file was closed successfully.\n"</span>); |
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139 <a name="l00148"></a>00148 } |
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140 <a name="l00149"></a>00149 <span class="keywordflow">else</span> |
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141 <a name="l00150"></a>00150 { |
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142 <a name="l00151"></a>00151 printf(<span class="stringliteral">"File close failed.\n"</span>); |
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143 <a name="l00152"></a>00152 } |
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144 <a name="l00153"></a>00153 |
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145 <a name="l00154"></a>00154 printf(<span class="stringliteral">"Press 'e'+Enter to exit from the sigusr1 process\n"</span>); |
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146 <a name="l00155"></a>00155 |
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147 <a name="l00156"></a>00156 <span class="keywordflow">while</span>((gch=getchar())!= <span class="charliteral">'e'</span>) |
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148 <a name="l00157"></a>00157 { |
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149 <a name="l00158"></a>00158 <span class="keywordflow">if</span>(gch == <span class="charliteral">'\n'</span>) |
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150 <a name="l00159"></a>00159 <span class="keywordflow">continue</span>; |
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151 <a name="l00160"></a>00160 <span class="keywordflow">else</span> |
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152 <a name="l00161"></a>00161 printf(<span class="stringliteral">"The wrong option was selected, please try again!!!\n"</span>); |
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153 <a name="l00162"></a>00162 } |
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154 <a name="l00163"></a>00163 <span class="keywordflow">return</span> EXIT_SUCCESS; |
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155 <a name="l00164"></a>00164 } |
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156 </pre></div><hr size="1"><address style="text-align: right;"><small>Generated on Thu Jan 21 10:33:00 2010 for TB10.1 Example Applications by |
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158 <img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.5.3 </small></address> |
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