sdl_semtrywait(3) centos man page | unix.com

SDL_SemTryWait(3)						 SDL API Reference						 SDL_SemTryWait(3)

NAME
       SDL_SemTryWait - Attempt to lock a semaphore but don't suspend the thread.

SYNOPSIS
       #include "SDL.h" #include "SDL_thread.h"

       int SDL_SemTryWait(SDL_sem *sem);

DESCRIPTION
       SDL_SemTryWait  is  a  non-blocking  varient of SDL_SemWait. If the value of the semaphore pointed to by sem is positive 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 successful 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)