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