WebSVN – Games.Prince of Persia – Blame – /SDL2.framework/Headers/SDL_mutex.h

Rev	Author	Line No.	Line
1	pmbaty	1	/*
		2	Simple DirectMedia Layer
		3	Copyright (C) 1997-2017 Sam Lantinga <slouken@libsdl.org>
		4
		5	This software is provided 'as-is', without any express or implied
		6	warranty. In no event will the authors be held liable for any damages
		7	arising from the use of this software.
		8
		9	Permission is granted to anyone to use this software for any purpose,
		10	including commercial applications, and to alter it and redistribute it
		11	freely, subject to the following restrictions:
		12
		13	1. The origin of this software must not be misrepresented; you must not
		14	claim that you wrote the original software. If you use this software
		15	in a product, an acknowledgment in the product documentation would be
		16	appreciated but is not required.
		17	2. Altered source versions must be plainly marked as such, and must not be
		18	misrepresented as being the original software.
		19	3. This notice may not be removed or altered from any source distribution.
		20	*/
		21
		22	#ifndef SDL_mutex_h_
		23	#define SDL_mutex_h_
		24
		25	/**
		26	* \file SDL_mutex.h
		27	*
		28	* Functions to provide thread synchronization primitives.
		29	*/
		30
		31	#include "SDL_stdinc.h"
		32	#include "SDL_error.h"
		33
		34	#include "begin_code.h"
		35	/* Set up for C function definitions, even when using C++ */
		36	#ifdef __cplusplus
		37	extern "C" {
		38	#endif
		39
		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	/**
		47	* This is the timeout value which corresponds to never time out.
		48	*/
		49	#define SDL_MUTEX_MAXWAIT (~(Uint32)0)
		50
		51
		52	/**
		53	* \name Mutex functions
		54	*/
		55	/* @{ */
		56
		57	/* The SDL mutex structure, defined in SDL_sysmutex.c */
		58	struct SDL_mutex;
		59	typedef struct SDL_mutex SDL_mutex;
		60
		61	/**
		62	* Create a mutex, initialized unlocked.
		63	*/
		64	extern DECLSPEC SDL_mutex *SDLCALL SDL_CreateMutex(void);
		65
		66	/**
		67	* Lock the mutex.
		68	*
		69	* \return 0, or -1 on error.
		70	*/
		71	#define SDL_mutexP(m) SDL_LockMutex(m)
		72	extern DECLSPEC int SDLCALL SDL_LockMutex(SDL_mutex * mutex);
		73
		74	/**
		75	* Try to lock the mutex
		76	*
		77	* \return 0, SDL_MUTEX_TIMEDOUT, or -1 on error
		78	*/
		79	extern DECLSPEC int SDLCALL SDL_TryLockMutex(SDL_mutex * mutex);
		80
		81	/**
		82	* Unlock the mutex.
		83	*
		84	* \return 0, or -1 on error.
		85	*
		86	* \warning It is an error to unlock a mutex that has not been locked by
		87	* the current thread, and doing so results in undefined behavior.
		88	*/
		89	#define SDL_mutexV(m) SDL_UnlockMutex(m)
		90	extern DECLSPEC int SDLCALL SDL_UnlockMutex(SDL_mutex * mutex);
		91
		92	/**
		93	* Destroy a mutex.
		94	*/
		95	extern DECLSPEC void SDLCALL SDL_DestroyMutex(SDL_mutex * mutex);
		96
		97	/* @} // Mutex functions */
		98
		99
		100	/**
		101	* \name Semaphore functions
		102	*/
		103	/* @{ */
		104
		105	/* The SDL semaphore structure, defined in SDL_syssem.c */
		106	struct SDL_semaphore;
		107	typedef struct SDL_semaphore SDL_sem;
		108
		109	/**
		110	* Create a semaphore, initialized with value, returns NULL on failure.
		111	*/
		112	extern DECLSPEC SDL_sem *SDLCALL SDL_CreateSemaphore(Uint32 initial_value);
		113
		114	/**
		115	* Destroy a semaphore.
		116	*/
		117	extern DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem * sem);
		118
		119	/**
		120	* This function suspends the calling thread until the semaphore pointed
		121	* to by \c sem has a positive count. It then atomically decreases the
		122	* semaphore count.
		123	*/
		124	extern DECLSPEC int SDLCALL SDL_SemWait(SDL_sem * sem);
		125
		126	/**
		127	* Non-blocking variant of SDL_SemWait().
		128	*
		129	* \return 0 if the wait succeeds, ::SDL_MUTEX_TIMEDOUT if the wait would
		130	* block, and -1 on error.
		131	*/
		132	extern DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem * sem);
		133
		134	/**
		135	* Variant of SDL_SemWait() with a timeout in milliseconds.
		136	*
		137	* \return 0 if the wait succeeds, ::SDL_MUTEX_TIMEDOUT if the wait does not
		138	* succeed in the allotted time, and -1 on error.
		139	*
		140	* \warning On some platforms this function is implemented by looping with a
		141	* delay of 1 ms, and so should be avoided if possible.
		142	*/
		143	extern DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem * sem, Uint32 ms);
		144
		145	/**
		146	* Atomically increases the semaphore's count (not blocking).
		147	*
		148	* \return 0, or -1 on error.
		149	*/
		150	extern DECLSPEC int SDLCALL SDL_SemPost(SDL_sem * sem);
		151
		152	/**
		153	* Returns the current count of the semaphore.
		154	*/
		155	extern DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem * sem);
		156
		157	/* @} // Semaphore functions */
		158
		159
		160	/**
		161	* \name Condition variable functions
		162	*/
		163	/* @{ */
		164
		165	/* The SDL condition variable structure, defined in SDL_syscond.c */
		166	struct SDL_cond;
		167	typedef struct SDL_cond SDL_cond;
		168
		169	/**
		170	* Create a condition variable.
		171	*
		172	* Typical use of condition variables:
		173	*
		174	* Thread A:
		175	* SDL_LockMutex(lock);
		176	* while ( ! condition ) {
		177	* SDL_CondWait(cond, lock);
		178	* }
		179	* SDL_UnlockMutex(lock);
		180	*
		181	* Thread B:
		182	* SDL_LockMutex(lock);
		183	* ...
		184	* condition = true;
		185	* ...
		186	* SDL_CondSignal(cond);
		187	* SDL_UnlockMutex(lock);
		188	*
		189	* There is some discussion whether to signal the condition variable
		190	* with the mutex locked or not. There is some potential performance
		191	* benefit to unlocking first on some platforms, but there are some
		192	* potential race conditions depending on how your code is structured.
		193	*
		194	* In general it's safer to signal the condition variable while the
		195	* mutex is locked.
		196	*/
		197	extern DECLSPEC SDL_cond *SDLCALL SDL_CreateCond(void);
		198
		199	/**
		200	* Destroy a condition variable.
		201	*/
		202	extern DECLSPEC void SDLCALL SDL_DestroyCond(SDL_cond * cond);
		203
		204	/**
		205	* Restart one of the threads that are waiting on the condition variable.
		206	*
		207	* \return 0 or -1 on error.
		208	*/
		209	extern DECLSPEC int SDLCALL SDL_CondSignal(SDL_cond * cond);
		210
		211	/**
		212	* Restart all threads that are waiting on the condition variable.
		213	*
		214	* \return 0 or -1 on error.
		215	*/
		216	extern DECLSPEC int SDLCALL SDL_CondBroadcast(SDL_cond * cond);
		217
		218	/**
		219	* Wait on the condition variable, unlocking the provided mutex.
		220	*
		221	* \warning The mutex must be locked before entering this function!
		222	*
		223	* The mutex is re-locked once the condition variable is signaled.
		224	*
		225	* \return 0 when it is signaled, or -1 on error.
		226	*/
		227	extern DECLSPEC int SDLCALL SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex);
		228
		229	/**
		230	* Waits for at most \c ms milliseconds, and returns 0 if the condition
		231	* variable is signaled, ::SDL_MUTEX_TIMEDOUT if the condition is not
		232	* signaled in the allotted time, and -1 on error.
		233	*
		234	* \warning On some platforms this function is implemented by looping with a
		235	* delay of 1 ms, and so should be avoided if possible.
		236	*/
		237	extern DECLSPEC int SDLCALL SDL_CondWaitTimeout(SDL_cond * cond,
		238	SDL_mutex * mutex, Uint32 ms);
		239
		240	/* @} // Condition variable functions */
		241
		242
		243	/* Ends C function definitions when using C++ */
		244	#ifdef __cplusplus
		245	}
		246	#endif
		247	#include "close_code.h"
		248
		249	#endif /* SDL_mutex_h_ */
		250
		251	/* vi: set ts=4 sw=4 expandtab: */

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Games.Prince of Persia/SDL2.framework/Headers/SDL_mutex.h – Rev 1