| /* |
| SDL - Simple DirectMedia Layer |
| Copyright (C) 1997-2009 Sam Lantinga |
| |
| This library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| This library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with this library; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| |
| Sam Lantinga |
| slouken@libsdl.org |
| */ |
| |
| #ifndef _SDL_mutex_h |
| #define _SDL_mutex_h |
| |
| /** @file SDL_mutex.h |
| * Functions to provide thread synchronization primitives |
| * |
| * @note These are independent of the other SDL routines. |
| */ |
| |
| #include "SDL_stdinc.h" |
| #include "SDL_error.h" |
| |
| #include "begin_code.h" |
| /* Set up for C function definitions, even when using C++ */ |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /** Synchronization functions which can time out return this value |
| * if they time out. |
| */ |
| #define SDL_MUTEX_TIMEDOUT 1 |
| |
| /** This is the timeout value which corresponds to never time out */ |
| #define SDL_MUTEX_MAXWAIT (~(Uint32)0) |
| |
| |
| /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| /** @name Mutex functions */ /*@{*/ |
| /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| |
| /** The SDL mutex structure, defined in SDL_mutex.c */ |
| struct SDL_mutex; |
| typedef struct SDL_mutex SDL_mutex; |
| |
| /** Create a mutex, initialized unlocked */ |
| extern DECLSPEC SDL_mutex * SDLCALL SDL_CreateMutex(void); |
| |
| #define SDL_LockMutex(m) SDL_mutexP(m) |
| /** Lock the mutex |
| * @return 0, or -1 on error |
| */ |
| extern DECLSPEC int SDLCALL SDL_mutexP(SDL_mutex *mutex); |
| |
| #define SDL_UnlockMutex(m) SDL_mutexV(m) |
| /** Unlock the mutex |
| * @return 0, or -1 on error |
| * |
| * It is an error to unlock a mutex that has not been locked by |
| * the current thread, and doing so results in undefined behavior. |
| */ |
| extern DECLSPEC int SDLCALL SDL_mutexV(SDL_mutex *mutex); |
| |
| /** Destroy a mutex */ |
| extern DECLSPEC void SDLCALL SDL_DestroyMutex(SDL_mutex *mutex); |
| |
| /*@}*/ |
| |
| /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| /** @name Semaphore functions */ /*@{*/ |
| /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| |
| /** The SDL semaphore structure, defined in SDL_sem.c */ |
| struct SDL_semaphore; |
| typedef struct SDL_semaphore SDL_sem; |
| |
| /** Create a semaphore, initialized with value, returns NULL on failure. */ |
| extern DECLSPEC SDL_sem * SDLCALL SDL_CreateSemaphore(Uint32 initial_value); |
| |
| /** Destroy a semaphore */ |
| extern DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem *sem); |
| |
| /** |
| * This function suspends the calling thread until the semaphore pointed |
| * to by sem has a positive count. It then atomically decreases the semaphore |
| * count. |
| */ |
| extern DECLSPEC int SDLCALL SDL_SemWait(SDL_sem *sem); |
| |
| /** Non-blocking variant of SDL_SemWait(). |
| * @return 0 if the wait succeeds, |
| * SDL_MUTEX_TIMEDOUT if the wait would block, and -1 on error. |
| */ |
| extern DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem *sem); |
| |
| /** Variant of SDL_SemWait() with a timeout in milliseconds, returns 0 if |
| * the wait succeeds, SDL_MUTEX_TIMEDOUT if the wait does not succeed in |
| * the allotted time, and -1 on error. |
| * |
| * On some platforms this function is implemented by looping with a delay |
| * of 1 ms, and so should be avoided if possible. |
| */ |
| extern DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem *sem, Uint32 ms); |
| |
| /** Atomically increases the semaphore's count (not blocking). |
| * @return 0, or -1 on error. |
| */ |
| extern DECLSPEC int SDLCALL SDL_SemPost(SDL_sem *sem); |
| |
| /** Returns the current count of the semaphore */ |
| extern DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem *sem); |
| |
| /*@}*/ |
| |
| /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| /** @name Condition_variable_functions */ /*@{*/ |
| /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| |
| /*@{*/ |
| /** The SDL condition variable structure, defined in SDL_cond.c */ |
| struct SDL_cond; |
| typedef struct SDL_cond SDL_cond; |
| /*@}*/ |
| |
| /** Create a condition variable */ |
| extern DECLSPEC SDL_cond * SDLCALL SDL_CreateCond(void); |
| |
| /** Destroy a condition variable */ |
| extern DECLSPEC void SDLCALL SDL_DestroyCond(SDL_cond *cond); |
| |
| /** Restart one of the threads that are waiting on the condition variable, |
| * @return 0 or -1 on error. |
| */ |
| extern DECLSPEC int SDLCALL SDL_CondSignal(SDL_cond *cond); |
| |
| /** Restart all threads that are waiting on the condition variable, |
| * @return 0 or -1 on error. |
| */ |
| extern DECLSPEC int SDLCALL SDL_CondBroadcast(SDL_cond *cond); |
| |
| /** Wait on the condition variable, unlocking the provided mutex. |
| * The mutex must be locked before entering this function! |
| * The mutex is re-locked once the condition variable is signaled. |
| * @return 0 when it is signaled, or -1 on error. |
| */ |
| extern DECLSPEC int SDLCALL SDL_CondWait(SDL_cond *cond, SDL_mutex *mut); |
| |
| /** Waits for at most 'ms' milliseconds, and returns 0 if the condition |
| * variable is signaled, SDL_MUTEX_TIMEDOUT if the condition is not |
| * signaled in the allotted time, and -1 on error. |
| * On some platforms this function is implemented by looping with a delay |
| * of 1 ms, and so should be avoided if possible. |
| */ |
| extern DECLSPEC int SDLCALL SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms); |
| |
| /*@}*/ |
| |
| /* Ends C function definitions when using C++ */ |
| #ifdef __cplusplus |
| } |
| #endif |
| #include "close_code.h" |
| |
| #endif /* _SDL_mutex_h */ |
| |