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SDL_CondWait

Use this function to wait until a condition variable is signaled.

Syntax

int SDL_CondWait(SDL_cond*  cond,
                 SDL_mutex* mutex)

Function Parameters

cond

the condition variable to wait on

mutex

the mutex used to coordinate thread access

Return Value

Returns 0 when it is signaled or a negative error code on failure; call SDL_GetError() for more information.

Code Examples

Typical use of condition variables:

SDL_bool condition = SDL_FALSE;
SDL_mutex *lock;
SDL_cond *cond;

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

Thread B:
    SDL_LockMutex(lock);
    ...
    condition = SDL_TRUE;
    ...
    SDL_CondSignal(cond);
    SDL_UnlockMutex(lock);
.
.
SDL_DestroyCond(cond);
SDL_DestroyMutex(lock);

Remarks

This function unlocks the specified mutex and waits for another thread to call SDL_CondSignal() or SDL_CondBroadcast() on the condition variable cond. Once the condition variable is signaled, the mutex is re-locked and the function returns.

The mutex must be locked before calling this function.

This function is the equivalent of calling SDL_CondWaitTimeout() with a time length of SDL_MUTEX_MAXWAIT.


CategoryAPI, CategoryMutex

None: SDL_CondWait (last edited 2015-04-26 19:04:51 by PhilippWiesemann)

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