Файл SDL_mutex.h

См. исходные тексты.

Mutex functions
typedef struct SDL_mutex	SDL_mutex
DECLSPEC SDL_mutex *SDLCALL	SDL_CreateMutex (void)
DECLSPEC int SDLCALL	SDL_LockMutex (SDL_mutex *mutex)
DECLSPEC int SDLCALL	SDL_TryLockMutex (SDL_mutex *mutex)
DECLSPEC int SDLCALL	SDL_UnlockMutex (SDL_mutex *mutex)
DECLSPEC void SDLCALL	SDL_DestroyMutex (SDL_mutex *mutex)

Semaphore functions
typedef struct SDL_semaphore	SDL_sem
DECLSPEC SDL_sem *SDLCALL	SDL_CreateSemaphore (Uint32 initial_value)
DECLSPEC void SDLCALL	SDL_DestroySemaphore (SDL_sem *sem)
DECLSPEC int SDLCALL	SDL_SemWait (SDL_sem *sem)
DECLSPEC int SDLCALL	SDL_SemTryWait (SDL_sem *sem)
DECLSPEC int SDLCALL	SDL_SemWaitTimeout (SDL_sem *sem, Uint32 ms)
DECLSPEC int SDLCALL	SDL_SemPost (SDL_sem *sem)
DECLSPEC Uint32 SDLCALL	SDL_SemValue (SDL_sem *sem)

Condition variable functions
typedef struct SDL_cond	SDL_cond
DECLSPEC SDL_cond *SDLCALL	SDL_CreateCond (void)
DECLSPEC void SDLCALL	SDL_DestroyCond (SDL_cond *cond)
DECLSPEC int SDLCALL	SDL_CondSignal (SDL_cond *cond)
DECLSPEC int SDLCALL	SDL_CondBroadcast (SDL_cond *cond)
DECLSPEC int SDLCALL	SDL_CondWait (SDL_cond *cond, SDL_mutex *mutex)
DECLSPEC int SDLCALL	SDL_CondWaitTimeout (SDL_cond *cond, SDL_mutex *mutex, Uint32 ms)

Подробное описание

Functions to provide thread synchronization primitives.

См. определение в файле SDL_mutex.h

Типы

SDL_mutex

typedef struct SDL_mutex SDL_mutex

См. определение в файле SDL_mutex.h строка 59

SDL_sem

typedef struct SDL_semaphore SDL_sem

См. определение в файле SDL_mutex.h строка 107

SDL_cond

typedef struct SDL_cond SDL_cond

См. определение в файле SDL_mutex.h строка 167

Функции

SDL_CreateMutex()

DECLSPEC SDL_mutex* SDLCALL SDL_CreateMutex

(

void

)

Create a mutex, initialized unlocked.

SDL_LockMutex()

DECLSPEC int SDLCALL SDL_LockMutex

(

SDL_mutex *

mutex

)

SDL_TryLockMutex()

DECLSPEC int SDLCALL SDL_TryLockMutex

(

SDL_mutex *

mutex

)

Try to lock the mutex

Возвращает

0, SDL_MUTEX_TIMEDOUT, or -1 on error

SDL_UnlockMutex()

DECLSPEC int SDLCALL SDL_UnlockMutex

(

SDL_mutex *

mutex

)

SDL_DestroyMutex()

DECLSPEC void SDLCALL SDL_DestroyMutex

(

SDL_mutex *

mutex

)

Destroy a mutex.

SDL_CreateSemaphore()

DECLSPEC SDL_sem* SDLCALL SDL_CreateSemaphore

(

Uint32

initial_value

)

Create a semaphore, initialized with value, returns NULL on failure.

SDL_DestroySemaphore()

DECLSPEC void SDLCALL SDL_DestroySemaphore

(

SDL_sem *

sem

)

Destroy a semaphore.

SDL_SemWait()

DECLSPEC int SDLCALL SDL_SemWait

(

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.

SDL_SemTryWait()

DECLSPEC int SDLCALL SDL_SemTryWait

(

SDL_sem *

sem

)

Non-blocking variant of SDL_SemWait().

Возвращает

0 if the wait succeeds, ::SDL_MUTEX_TIMEDOUT if the wait would block, and -1 on error.

SDL_SemWaitTimeout()

DECLSPEC int SDLCALL SDL_SemWaitTimeout	(	SDL_sem *	sem,
		Uint32	ms
	)

Variant of SDL_SemWait() with a timeout in milliseconds.

Возвращает

0 if the wait succeeds, ::SDL_MUTEX_TIMEDOUT if the wait does not succeed in the allotted time, and -1 on error.

Предупреждения

On some platforms this function is implemented by looping with a delay of 1 ms, and so should be avoided if possible.

SDL_SemPost()

DECLSPEC int SDLCALL SDL_SemPost

(

SDL_sem *

sem

)

Atomically increases the semaphore's count (not blocking).

Возвращает

0, or -1 on error.

SDL_SemValue()

DECLSPEC Uint32 SDLCALL SDL_SemValue

(

SDL_sem *

sem

)

Returns the current count of the semaphore.

SDL_CreateCond()

DECLSPEC SDL_cond* SDLCALL SDL_CreateCond

(

void

)

Create a condition variable.

Typical use of condition variables:

Thread A: SDL_LockMutex(lock); while ( ! condition ) { SDL_CondWait(cond, lock); } SDL_UnlockMutex(lock);

Thread B: SDL_LockMutex(lock); ... condition = true; ... SDL_CondSignal(cond); SDL_UnlockMutex(lock);

There is some discussion whether to signal the condition variable with the mutex locked or not. There is some potential performance benefit to unlocking first on some platforms, but there are some potential race conditions depending on how your code is structured.

In general it's safer to signal the condition variable while the mutex is locked.

SDL_DestroyCond()

DECLSPEC void SDLCALL SDL_DestroyCond

(

SDL_cond *

cond

)

Destroy a condition variable.

SDL_CondSignal()

DECLSPEC int SDLCALL SDL_CondSignal

(

SDL_cond *

cond

)

Restart one of the threads that are waiting on the condition variable.

Возвращает

0 or -1 on error.

SDL_CondBroadcast()

DECLSPEC int SDLCALL SDL_CondBroadcast

(

SDL_cond *

cond

)

Restart all threads that are waiting on the condition variable.

Возвращает

0 or -1 on error.

SDL_CondWait()

DECLSPEC int SDLCALL SDL_CondWait	(	SDL_cond *	cond,
		SDL_mutex *	mutex
	)

Wait on the condition variable, unlocking the provided mutex.

Предупреждения

The mutex must be locked before entering this function!

The mutex is re-locked once the condition variable is signaled.

Возвращает

0 when it is signaled, or -1 on error.

SDL_CondWaitTimeout()

DECLSPEC int SDLCALL SDL_CondWaitTimeout	(	SDL_cond *	cond,
		SDL_mutex *	mutex,
		Uint32	ms
	)

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.

Предупреждения

On some platforms this function is implemented by looping with a delay of 1 ms, and so should be avoided if possible.