| 1 | /* |
| 2 | SDL - Simple DirectMedia Layer |
| 3 | Copyright (C) 1997-2009 Sam Lantinga |
| 4 | |
| 5 | This library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | This library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with this library; if not, write to the Free Software |
| 17 | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | |
| 19 | Sam Lantinga |
| 20 | slouken@libsdl.org |
| 21 | */ |
| 22 | |
| 23 | #ifndef _SDL_mutex_h |
| 24 | #define _SDL_mutex_h |
| 25 | |
| 26 | /** @file SDL_mutex.h |
| 27 | * Functions to provide thread synchronization primitives |
| 28 | * |
| 29 | * @note These are independent of the other SDL routines. |
| 30 | */ |
| 31 | |
| 32 | #include "SDL_stdinc.h" |
| 33 | #include "SDL_error.h" |
| 34 | |
| 35 | #include "begin_code.h" |
| 36 | /* Set up for C function definitions, even when using C++ */ |
| 37 | #ifdef __cplusplus |
| 38 | extern "C" { |
| 39 | #endif |
| 40 | |
| 41 | /** Synchronization functions which can time out return this value |
| 42 | * if they time out. |
| 43 | */ |
| 44 | #define SDL_MUTEX_TIMEDOUT 1 |
| 45 | |
| 46 | /** This is the timeout value which corresponds to never time out */ |
| 47 | #define SDL_MUTEX_MAXWAIT (~(Uint32)0) |
| 48 | |
| 49 | |
| 50 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| 51 | /** @name Mutex functions */ /*@{*/ |
| 52 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| 53 | |
| 54 | /** The SDL mutex structure, defined in SDL_mutex.c */ |
| 55 | struct SDL_mutex; |
| 56 | typedef struct SDL_mutex SDL_mutex; |
| 57 | |
| 58 | /** Create a mutex, initialized unlocked */ |
| 59 | extern DECLSPEC SDL_mutex * SDLCALL SDL_CreateMutex(void); |
| 60 | |
| 61 | #define SDL_LockMutex(m) SDL_mutexP(m) |
| 62 | /** Lock the mutex |
| 63 | * @return 0, or -1 on error |
| 64 | */ |
| 65 | extern DECLSPEC int SDLCALL SDL_mutexP(SDL_mutex *mutex); |
| 66 | |
| 67 | #define SDL_UnlockMutex(m) SDL_mutexV(m) |
| 68 | /** Unlock the mutex |
| 69 | * @return 0, or -1 on error |
| 70 | * |
| 71 | * It is an error to unlock a mutex that has not been locked by |
| 72 | * the current thread, and doing so results in undefined behavior. |
| 73 | */ |
| 74 | extern DECLSPEC int SDLCALL SDL_mutexV(SDL_mutex *mutex); |
| 75 | |
| 76 | /** Destroy a mutex */ |
| 77 | extern DECLSPEC void SDLCALL SDL_DestroyMutex(SDL_mutex *mutex); |
| 78 | |
| 79 | /*@}*/ |
| 80 | |
| 81 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| 82 | /** @name Semaphore functions */ /*@{*/ |
| 83 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| 84 | |
| 85 | /** The SDL semaphore structure, defined in SDL_sem.c */ |
| 86 | struct SDL_semaphore; |
| 87 | typedef struct SDL_semaphore SDL_sem; |
| 88 | |
| 89 | /** Create a semaphore, initialized with value, returns NULL on failure. */ |
| 90 | extern DECLSPEC SDL_sem * SDLCALL SDL_CreateSemaphore(Uint32 initial_value); |
| 91 | |
| 92 | /** Destroy a semaphore */ |
| 93 | extern DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem *sem); |
| 94 | |
| 95 | /** |
| 96 | * This function suspends the calling thread until the semaphore pointed |
| 97 | * to by sem has a positive count. It then atomically decreases the semaphore |
| 98 | * count. |
| 99 | */ |
| 100 | extern DECLSPEC int SDLCALL SDL_SemWait(SDL_sem *sem); |
| 101 | |
| 102 | /** Non-blocking variant of SDL_SemWait(). |
| 103 | * @return 0 if the wait succeeds, |
| 104 | * SDL_MUTEX_TIMEDOUT if the wait would block, and -1 on error. |
| 105 | */ |
| 106 | extern DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem *sem); |
| 107 | |
| 108 | /** Variant of SDL_SemWait() with a timeout in milliseconds, returns 0 if |
| 109 | * the wait succeeds, SDL_MUTEX_TIMEDOUT if the wait does not succeed in |
| 110 | * the allotted time, and -1 on error. |
| 111 | * |
| 112 | * On some platforms this function is implemented by looping with a delay |
| 113 | * of 1 ms, and so should be avoided if possible. |
| 114 | */ |
| 115 | extern DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem *sem, Uint32 ms); |
| 116 | |
| 117 | /** Atomically increases the semaphore's count (not blocking). |
| 118 | * @return 0, or -1 on error. |
| 119 | */ |
| 120 | extern DECLSPEC int SDLCALL SDL_SemPost(SDL_sem *sem); |
| 121 | |
| 122 | /** Returns the current count of the semaphore */ |
| 123 | extern DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem *sem); |
| 124 | |
| 125 | /*@}*/ |
| 126 | |
| 127 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| 128 | /** @name Condition_variable_functions */ /*@{*/ |
| 129 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| 130 | |
| 131 | /*@{*/ |
| 132 | /** The SDL condition variable structure, defined in SDL_cond.c */ |
| 133 | struct SDL_cond; |
| 134 | typedef struct SDL_cond SDL_cond; |
| 135 | /*@}*/ |
| 136 | |
| 137 | /** Create a condition variable */ |
| 138 | extern DECLSPEC SDL_cond * SDLCALL SDL_CreateCond(void); |
| 139 | |
| 140 | /** Destroy a condition variable */ |
| 141 | extern DECLSPEC void SDLCALL SDL_DestroyCond(SDL_cond *cond); |
| 142 | |
| 143 | /** Restart one of the threads that are waiting on the condition variable, |
| 144 | * @return 0 or -1 on error. |
| 145 | */ |
| 146 | extern DECLSPEC int SDLCALL SDL_CondSignal(SDL_cond *cond); |
| 147 | |
| 148 | /** Restart all threads that are waiting on the condition variable, |
| 149 | * @return 0 or -1 on error. |
| 150 | */ |
| 151 | extern DECLSPEC int SDLCALL SDL_CondBroadcast(SDL_cond *cond); |
| 152 | |
| 153 | /** Wait on the condition variable, unlocking the provided mutex. |
| 154 | * The mutex must be locked before entering this function! |
| 155 | * The mutex is re-locked once the condition variable is signaled. |
| 156 | * @return 0 when it is signaled, or -1 on error. |
| 157 | */ |
| 158 | extern DECLSPEC int SDLCALL SDL_CondWait(SDL_cond *cond, SDL_mutex *mut); |
| 159 | |
| 160 | /** Waits for at most 'ms' milliseconds, and returns 0 if the condition |
| 161 | * variable is signaled, SDL_MUTEX_TIMEDOUT if the condition is not |
| 162 | * signaled in the allotted time, and -1 on error. |
| 163 | * On some platforms this function is implemented by looping with a delay |
| 164 | * of 1 ms, and so should be avoided if possible. |
| 165 | */ |
| 166 | extern DECLSPEC int SDLCALL SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms); |
| 167 | |
| 168 | /*@}*/ |
| 169 | |
| 170 | /* Ends C function definitions when using C++ */ |
| 171 | #ifdef __cplusplus |
| 172 | } |
| 173 | #endif |
| 174 | #include "close_code.h" |
| 175 | |
| 176 | #endif /* _SDL_mutex_h */ |
| 177 | |