SDL_SemWaitTimeout(3)   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
       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.

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                    1