Manual Pages for UNIX Operating System command usage for man SDL_SemWaitTimeout

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 max-
     imum 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 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 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            Last change: Tue 11 Sep 2001, 23:00              1