SDL_SemWaitTimeout(3) SDL API Reference SDL_SemWaitTimeout(3)
NAME
SDL_SemWaitTimeout - Lock a semaphore, but only wait up to a specified
maximum time.
SYNOPSIS
#include "SDL.h" #include "SDL_thread.h"
int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout);
DESCRIPTION
SDL_SemWaitTimeout() is a varient of SDL_SemWait with a maximum timeout
value. If the value of the semaphore pointed to by sem is positive
(greater than zero) it will atomically decrement the semaphore value
and return 0, otherwise it will wait up to timeout milliseconds trying
to lock the semaphore. This function is to be avoided if possible since
on some platforms it is implemented by polling the semaphore every mil-
lisecond in a busy loop.
After SDL_SemWaitTimeout() is successful, the semaphore can be released
and its count atomically incremented by a successful call to SDL_Sem-
Post.
RETURN VALUE
Returns 0 if the semaphore was successfully locked or either SDL_MU-
TEX_TIMEOUT or -1 if the timeout period was exceeded or there was an
error, respectivly.
If the semaphore was not successfully locked, the semaphore will be un-
changed.
EXAMPLES
res = SDL_SemWaitTimeout(my_sem, WAIT_TIMEOUT_MILLISEC);
if (res == SDL_MUTEX_TIMEOUT) {
return TRY_AGAIN;
}
if (res == -1) {
return WAIT_ERROR;
}
...
SDL_SemPost(my_sem);
SEE ALSO
SDL_CreateSemaphore, SDL_DestroySemaphore, SDL_SemWait, SDL_SemTryWait,
SDL_SemPost, SDL_SemValue
SDL Tue 11 Sep 2001, 23:00 SDL_SemWaitTimeout(3)
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