SDL_SemWaitTimeout - Lock a semaphore, but only wait up to a specified maximum time.
Contents
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.
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);
Name
SDL_SemWaitTimeout - Lock a semaphore, but only wait up to a specified maximum time.
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.
See Also
SDL_CreateSemaphore, SDL_DestroySemaphore, SDL_SemWait, SDL_SemTryWait, SDL_SemPost, SDL_SemValue
SDL Tue 11 Sep 2001, 23:00 SDL_SemWaitTimeout(3)
Synopsis
#include"SDL.h"#include"SDL_thread.h"intSDL_SemWaitTimeout(SDL_sem*sem,Uint32timeout);
