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_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)