SDL_SemTryWait(3) SDL API Reference SDL_SemTryWait(3)NAME
SDL_SemTryWait- Attempt to lock a semaphore but don't sus-
pend the thread.
SYNOPSIS
#include "SDL.h" #include "SDL_thread.h"
int SDL_SemTryWait(SDL_sem *sem);
DESCRIPTIONSDL_SemTryWait is a non-blocking varient of SDL_SemWait.
If the value of the semaphore pointed to by sem is posi-
tive it will atomically decrement the semaphore value and
return 0, otherwise it will return SDL_MUTEX_TIMEOUT
instead of suspending the thread.
After SDL_SemTryWait is successful, the semaphore can be
released and its count atomically incremented by a suc-
cessful call to SDL_SemPost.
RETURN VALUE
Returns 0 if the semaphore was successfully locked or
either SDL_MUTEX_TIMEOUT or -1 if the thread would have
suspended or there was an error, respectivly.
If the semaphore was not successfully locked, the
semaphore will be unchanged.
EXAMPLES
res = SDL_SemTryWait(my_sem);
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_SemWaitTimeout, SDL_SemPost, SDL_SemValue
SDL Tue 11 Sep 2001, 23:00 SDL_SemTryWait(3)
