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| Rev | Author | Line No. | Line |
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| 3 | pmbaty | 1 | /* |
| 2 | SDL - Simple DirectMedia Layer |
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| 3 | Copyright (C) 1997-2009 Sam Lantinga |
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| 4 | |||
| 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 Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |||
| 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 | Lesser General Public License for more details. |
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| 14 | |||
| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with this library; if not, write to the Free Software |
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| 17 | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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| 18 | |||
| 19 | Sam Lantinga |
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| 20 | slouken@libsdl.org |
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| 21 | */ |
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| 22 | |||
| 23 | #ifndef _SDL_mutex_h |
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| 24 | #define _SDL_mutex_h |
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| 25 | |||
| 26 | /** @file SDL_mutex.h |
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| 27 | * Functions to provide thread synchronization primitives |
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| 28 | * |
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| 29 | * @note These are independent of the other SDL routines. |
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| 30 | */ |
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| 31 | |||
| 32 | #include "SDL_stdinc.h" |
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| 33 | #include "SDL_error.h" |
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| 34 | |||
| 35 | #include "begin_code.h" |
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| 36 | /* Set up for C function definitions, even when using C++ */ |
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| 37 | #ifdef __cplusplus |
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| 38 | extern "C" { |
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| 39 | #endif |
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| 40 | |||
| 41 | /** Synchronization functions which can time out return this value |
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| 42 | * if they time out. |
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| 43 | */ |
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| 44 | #define SDL_MUTEX_TIMEDOUT 1 |
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| 45 | |||
| 46 | /** This is the timeout value which corresponds to never time out */ |
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| 47 | #define SDL_MUTEX_MAXWAIT (~(Uint32)0) |
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| 48 | |||
| 49 | |||
| 50 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
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| 51 | /** @name Mutex functions */ /*@{*/ |
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| 52 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
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| 53 | |||
| 54 | /** The SDL mutex structure, defined in SDL_mutex.c */ |
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| 55 | struct SDL_mutex; |
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| 56 | typedef struct SDL_mutex SDL_mutex; |
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| 57 | |||
| 58 | /** Create a mutex, initialized unlocked */ |
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| 59 | extern DECLSPEC SDL_mutex * SDLCALL SDL_CreateMutex(void); |
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| 60 | |||
| 61 | #define SDL_LockMutex(m) SDL_mutexP(m) |
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| 62 | /** Lock the mutex |
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| 63 | * @return 0, or -1 on error |
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| 64 | */ |
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| 65 | extern DECLSPEC int SDLCALL SDL_mutexP(SDL_mutex *mutex); |
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| 66 | |||
| 67 | #define SDL_UnlockMutex(m) SDL_mutexV(m) |
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| 68 | /** Unlock the mutex |
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| 69 | * @return 0, or -1 on error |
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| 70 | * |
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| 71 | * It is an error to unlock a mutex that has not been locked by |
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| 72 | * the current thread, and doing so results in undefined behavior. |
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| 73 | */ |
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| 74 | extern DECLSPEC int SDLCALL SDL_mutexV(SDL_mutex *mutex); |
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| 75 | |||
| 76 | /** Destroy a mutex */ |
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| 77 | extern DECLSPEC void SDLCALL SDL_DestroyMutex(SDL_mutex *mutex); |
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| 78 | |||
| 79 | /*@}*/ |
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| 80 | |||
| 81 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
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| 82 | /** @name Semaphore functions */ /*@{*/ |
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| 83 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
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| 84 | |||
| 85 | /** The SDL semaphore structure, defined in SDL_sem.c */ |
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| 86 | struct SDL_semaphore; |
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| 87 | typedef struct SDL_semaphore SDL_sem; |
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| 88 | |||
| 89 | /** Create a semaphore, initialized with value, returns NULL on failure. */ |
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| 90 | extern DECLSPEC SDL_sem * SDLCALL SDL_CreateSemaphore(Uint32 initial_value); |
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| 91 | |||
| 92 | /** Destroy a semaphore */ |
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| 93 | extern DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem *sem); |
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| 94 | |||
| 95 | /** |
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| 96 | * This function suspends the calling thread until the semaphore pointed |
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| 97 | * to by sem has a positive count. It then atomically decreases the semaphore |
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| 98 | * count. |
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| 99 | */ |
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| 100 | extern DECLSPEC int SDLCALL SDL_SemWait(SDL_sem *sem); |
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| 101 | |||
| 102 | /** Non-blocking variant of SDL_SemWait(). |
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| 103 | * @return 0 if the wait succeeds, |
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| 104 | * SDL_MUTEX_TIMEDOUT if the wait would block, and -1 on error. |
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| 105 | */ |
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| 106 | extern DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem *sem); |
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| 107 | |||
| 108 | /** Variant of SDL_SemWait() with a timeout in milliseconds, returns 0 if |
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| 109 | * the wait succeeds, SDL_MUTEX_TIMEDOUT if the wait does not succeed in |
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| 110 | * the allotted time, and -1 on error. |
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| 111 | * |
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| 112 | * On some platforms this function is implemented by looping with a delay |
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| 113 | * of 1 ms, and so should be avoided if possible. |
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| 114 | */ |
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| 115 | extern DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem *sem, Uint32 ms); |
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| 116 | |||
| 117 | /** Atomically increases the semaphore's count (not blocking). |
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| 118 | * @return 0, or -1 on error. |
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| 119 | */ |
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| 120 | extern DECLSPEC int SDLCALL SDL_SemPost(SDL_sem *sem); |
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| 121 | |||
| 122 | /** Returns the current count of the semaphore */ |
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| 123 | extern DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem *sem); |
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| 124 | |||
| 125 | /*@}*/ |
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| 126 | |||
| 127 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
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| 128 | /** @name Condition_variable_functions */ /*@{*/ |
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| 129 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
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| 130 | |||
| 131 | /*@{*/ |
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| 132 | /** The SDL condition variable structure, defined in SDL_cond.c */ |
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| 133 | struct SDL_cond; |
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| 134 | typedef struct SDL_cond SDL_cond; |
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| 135 | /*@}*/ |
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| 136 | |||
| 137 | /** Create a condition variable */ |
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| 138 | extern DECLSPEC SDL_cond * SDLCALL SDL_CreateCond(void); |
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| 139 | |||
| 140 | /** Destroy a condition variable */ |
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| 141 | extern DECLSPEC void SDLCALL SDL_DestroyCond(SDL_cond *cond); |
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| 142 | |||
| 143 | /** Restart one of the threads that are waiting on the condition variable, |
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| 144 | * @return 0 or -1 on error. |
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| 145 | */ |
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| 146 | extern DECLSPEC int SDLCALL SDL_CondSignal(SDL_cond *cond); |
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| 147 | |||
| 148 | /** Restart all threads that are waiting on the condition variable, |
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| 149 | * @return 0 or -1 on error. |
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| 150 | */ |
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| 151 | extern DECLSPEC int SDLCALL SDL_CondBroadcast(SDL_cond *cond); |
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| 152 | |||
| 153 | /** Wait on the condition variable, unlocking the provided mutex. |
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| 154 | * The mutex must be locked before entering this function! |
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| 155 | * The mutex is re-locked once the condition variable is signaled. |
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| 156 | * @return 0 when it is signaled, or -1 on error. |
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| 157 | */ |
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| 158 | extern DECLSPEC int SDLCALL SDL_CondWait(SDL_cond *cond, SDL_mutex *mut); |
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| 159 | |||
| 160 | /** Waits for at most 'ms' milliseconds, and returns 0 if the condition |
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| 161 | * variable is signaled, SDL_MUTEX_TIMEDOUT if the condition is not |
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| 162 | * signaled in the allotted time, and -1 on error. |
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| 163 | * On some platforms this function is implemented by looping with a delay |
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| 164 | * of 1 ms, and so should be avoided if possible. |
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| 165 | */ |
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| 166 | extern DECLSPEC int SDLCALL SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms); |
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| 167 | |||
| 168 | /*@}*/ |
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| 169 | |||
| 170 | /* Ends C function definitions when using C++ */ |
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| 171 | #ifdef __cplusplus |
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| 172 | } |
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| 173 | #endif |
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| 174 | #include "close_code.h" |
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| 175 | |||
| 176 | #endif /* _SDL_mutex_h */ |
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| 177 |