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1190
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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga
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4
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5 This library is free software; you can redistribute it and/or
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6 modify it under the terms of the GNU Library General Public
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7 License as published by the Free Software Foundation; either
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8 version 2 of the License, or (at your option) any later version.
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9
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10 This library is distributed in the hope that it will be useful,
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 Library General Public License for more details.
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14
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15 You should have received a copy of the GNU Library General Public
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16 License along with this library; if not, write to the Free
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17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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18
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19 Sam Lantinga
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20 slouken@libsdl.org
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21 */
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22
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23 #ifdef SAVE_RCSID
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24 static char rcsid =
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25 "@(#) $Id$";
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26 #endif
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27
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28 /* Semaphore functions using the OS/2 API */
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29
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30 #include <stdio.h>
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31 #include <stdlib.h>
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32 #define INCL_DOS
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33 #define INCL_DOSERRORS
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34 #define INCL_DOSSEMAPHORES
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35 #include <os2.h>
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36
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37 #include "SDL_error.h"
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38 #include "SDL_thread.h"
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39 #include "SDL_timer.h"
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40
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41
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42 struct SDL_semaphore {
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43 HMTX id;
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44 HEV changed;
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45 Uint32 value;
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46 };
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47
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48
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49 /* Create a semaphore */
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50 DECLSPEC SDL_sem * SDLCALL SDL_CreateSemaphore(Uint32 initial_value)
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51 {
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52 SDL_sem *sem;
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53 ULONG ulrc;
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54
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55 /* Allocate sem memory */
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56 sem = (SDL_sem *)malloc(sizeof(*sem));
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57 if ( sem ) {
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58 /* Create the mutex semaphore */
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59 ulrc = DosCreateMutexSem(NULL,&(sem->id),0,TRUE);
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60 if ( ulrc ) {
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61 SDL_SetError("Couldn't create semaphore");
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62 free(sem);
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63 sem = NULL;
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64 } else
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65 {
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66 DosCreateEventSem(NULL, &(sem->changed), 0, FALSE);
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67 sem->value = initial_value;
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68 DosReleaseMutexSem(sem->id);
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69 }
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70 } else {
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71 SDL_OutOfMemory();
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72 }
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73 return(sem);
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74 }
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75
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76 /* Free the semaphore */
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77 DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem *sem)
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78 {
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79 if ( sem ) {
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80 if ( sem->id ) {
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81 DosCloseEventSem(sem->changed);
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82 DosCloseMutexSem(sem->id);
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83 sem->id = 0;
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84 }
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85 free(sem);
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86 }
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87 }
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88
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89 DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
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90 {
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91 ULONG ulrc;
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92
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93 if ( ! sem ) {
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94 SDL_SetError("Passed a NULL sem");
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95 return -1;
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96 }
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97
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98 if ( timeout == SDL_MUTEX_MAXWAIT ) {
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99 while (1) {
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100 ulrc = DosRequestMutexSem(sem->id, SEM_INDEFINITE_WAIT);
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101 if (ulrc) {
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102 /* if error waiting mutex */
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103 SDL_SetError("DosRequestMutexSem() failed");
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104 return -1;
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105 } else if (sem->value) {
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106 sem->value--;
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107 DosReleaseMutexSem(sem->id);
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108 return 0;
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109 } else {
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110 ULONG ulPostCount;
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111 DosResetEventSem(sem->changed, &ulPostCount);
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112 DosReleaseMutexSem(sem->id);
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113 /* continue waiting until somebody posts the semaphore */
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114 DosWaitEventSem(sem->changed, SEM_INDEFINITE_WAIT);
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115 }
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116 }
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117 } else
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118 if ( timeout == 0 )
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119 {
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120 ulrc = DosRequestMutexSem(sem->id, SEM_INDEFINITE_WAIT);
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121 if (ulrc==NO_ERROR)
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122 {
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123 if (sem->value)
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124 {
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125 sem->value--;
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126 DosReleaseMutexSem(sem->id);
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127 return 0;
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128 } else
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129 {
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130 DosReleaseMutexSem(sem->id);
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131 return SDL_MUTEX_TIMEDOUT;
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132 }
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133 } else
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134 {
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135 SDL_SetError("DosRequestMutexSem() failed");
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136 return -1;
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137 }
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138 } else {
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139 ulrc = DosRequestMutexSem(sem->id, SEM_INDEFINITE_WAIT);
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140 if (ulrc) {
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141 /* if error waiting mutex */
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142 SDL_SetError("DosRequestMutexSem() failed");
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143 return -1;
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144 } else
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145 if (sem->value) {
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146 sem->value--;
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147 DosReleaseMutexSem(sem->id);
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148 return 0;
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149 } else {
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150 ULONG ulPostCount;
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151 DosResetEventSem(sem->changed, &ulPostCount);
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152 DosReleaseMutexSem(sem->id);
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153 /* continue waiting until somebody posts the semaphore */
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154 ulrc = DosWaitEventSem(sem->changed, timeout);
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155 if (ulrc==NO_ERROR)
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156 return 0;
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157 else
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158 return SDL_MUTEX_TIMEDOUT;
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159 }
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160 }
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161 /* never reached */
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162 return -1;
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163 }
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164
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165 DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem *sem)
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166 {
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167 return SDL_SemWaitTimeout(sem, 0);
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168 }
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169
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170 DECLSPEC int SDLCALL SDL_SemWait(SDL_sem *sem)
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171 {
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172 return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
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173 }
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174
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175 /* Returns the current count of the semaphore */
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176 DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem *sem)
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177 {
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178 if ( ! sem ) {
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179 SDL_SetError("Passed a NULL sem");
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180 return 0;
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181 }
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182 return sem->value;
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183 }
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184
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185 DECLSPEC int SDLCALL SDL_SemPost(SDL_sem *sem)
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186 {
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187 if ( ! sem ) {
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188 SDL_SetError("Passed a NULL sem");
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189 return -1;
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190 }
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191 if ( DosRequestMutexSem(sem->id,SEM_INDEFINITE_WAIT) ) {
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192 SDL_SetError("DosRequestMutexSem() failed");
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193 return -1;
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194 }
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195 sem->value++;
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196 DosPostEventSem(sem->changed);
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197 DosReleaseMutexSem(sem->id);
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198 return 0;
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199 }
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