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