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 millisecond 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_SemPost.

RETURN VALUE

Returns 0 if the semaphore was successfully locked or either
SDL_MUTEX_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
unchanged.

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)