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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 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@devolution.com
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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 #ifndef _SDL_mutex_h
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29 #define _SDL_mutex_h
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30
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31 /* Functions to provide thread synchronization primitives
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32
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33 These are independent of the other SDL routines.
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34 */
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35
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36 #include "SDL_main.h"
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37 #include "SDL_types.h"
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38
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39 #include "begin_code.h"
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40 /* Set up for C function definitions, even when using C++ */
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41 #ifdef __cplusplus
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42 extern "C" {
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43 #endif
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44
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45 /* Synchronization functions which can time out return this value
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46 if they time out.
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47 */
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48 #define SDL_MUTEX_TIMEDOUT 1
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49
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50 /* This is the timeout value which corresponds to never time out */
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51 #define SDL_MUTEX_MAXWAIT (~(Uint32)0)
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52
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53
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54 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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55 /* Mutex functions */
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56 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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57
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58 /* The SDL mutex structure, defined in SDL_mutex.c */
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59 struct SDL_mutex;
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60 typedef struct SDL_mutex SDL_mutex;
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61
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62 /* Create a mutex, initialized unlocked */
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63 extern DECLSPEC SDL_mutex * SDL_CreateMutex(void);
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64
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65 /* Lock the mutex (Returns 0, or -1 on error) */
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66 #define SDL_LockMutex(m) SDL_mutexP(m)
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67 extern DECLSPEC int SDL_mutexP(SDL_mutex *mutex);
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68
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69 /* Unlock the mutex (Returns 0, or -1 on error) */
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70 #define SDL_UnlockMutex(m) SDL_mutexV(m)
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71 extern DECLSPEC int SDL_mutexV(SDL_mutex *mutex);
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72
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73 /* Destroy a mutex */
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74 extern DECLSPEC void SDL_DestroyMutex(SDL_mutex *mutex);
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75
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76
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77 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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78 /* Semaphore functions */
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79 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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80
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81 /* The SDL semaphore structure, defined in SDL_sem.c */
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82 struct SDL_semaphore;
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83 typedef struct SDL_semaphore SDL_sem;
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84
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85 /* Create a semaphore, initialized with value, returns NULL on failure. */
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86 extern DECLSPEC SDL_sem * SDL_CreateSemaphore(Uint32 initial_value);
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87
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88 /* Destroy a semaphore */
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89 extern DECLSPEC void SDL_DestroySemaphore(SDL_sem *sem);
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90
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91 /* This function suspends the calling thread until the semaphore pointed
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92 * to by sem has a positive count. It then atomically decreases the semaphore
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93 * count.
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94 */
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95 extern DECLSPEC int SDL_SemWait(SDL_sem *sem);
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96
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97 /* Non-blocking variant of SDL_SemWait(), returns 0 if the wait succeeds,
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98 SDL_MUTEX_TIMEDOUT if the wait would block, and -1 on error.
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99 */
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100 extern DECLSPEC int SDL_SemTryWait(SDL_sem *sem);
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101
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102 /* Variant of SDL_SemWait() with a timeout in milliseconds, returns 0 if
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103 the wait succeeds, SDL_MUTEX_TIMEDOUT if the wait does not succeed in
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104 the allotted time, and -1 on error.
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105 On some platforms this function is implemented by looping with a delay
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106 of 1 ms, and so should be avoided if possible.
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107 */
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108 extern DECLSPEC int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 ms);
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109
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110 /* Atomically increases the semaphore's count (not blocking), returns 0,
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111 or -1 on error.
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112 */
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113 extern DECLSPEC int SDL_SemPost(SDL_sem *sem);
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114
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115 /* Returns the current count of the semaphore */
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116 extern DECLSPEC Uint32 SDL_SemValue(SDL_sem *sem);
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117
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118
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119 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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120 /* Condition variable functions */
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121 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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122
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123 /* The SDL condition variable structure, defined in SDL_cond.c */
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124 struct SDL_cond;
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125 typedef struct SDL_cond SDL_cond;
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126
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127 /* Create a condition variable */
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128 extern DECLSPEC SDL_cond * SDL_CreateCond(void);
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129
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130 /* Destroy a condition variable */
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131 extern DECLSPEC void SDL_DestroyCond(SDL_cond *cond);
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132
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133 /* Restart one of the threads that are waiting on the condition variable,
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134 returns 0 or -1 on error.
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135 */
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136 extern DECLSPEC int SDL_CondSignal(SDL_cond *cond);
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137
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138 /* Restart all threads that are waiting on the condition variable,
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139 returns 0 or -1 on error.
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140 */
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141 extern DECLSPEC int SDL_CondBroadcast(SDL_cond *cond);
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142
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143 /* Wait on the condition variable, unlocking the provided mutex.
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144 The mutex must be locked before entering this function!
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145 Returns 0 when it is signaled, or -1 on error.
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146 */
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147 extern DECLSPEC int SDL_CondWait(SDL_cond *cond, SDL_mutex *mut);
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148
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149 /* Waits for at most 'ms' milliseconds, and returns 0 if the condition
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150 variable is signaled, SDL_MUTEX_TIMEDOUT if the condition is not
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151 signaled in the allotted time, and -1 on error.
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152 On some platforms this function is implemented by looping with a delay
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153 of 1 ms, and so should be avoided if possible.
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154 */
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155 extern DECLSPEC int SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms);
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156
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157 /* Ends C function definitions when using C++ */
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158 #ifdef __cplusplus
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159 }
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160 #endif
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161 #include "close_code.h"
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162
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163 #endif /* _SDL_mutex_h */
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