NAME

       SDL_SemWait - Lock a semaphore and suspend the thread if the semaphore value is zero.

SYNOPSIS

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

       int SDL_SemWait(SDL_sem *sem);

DESCRIPTION

       SDL_SemWait() suspends the calling thread until either the semaphore pointed to by sem has
       a positive value, the call is interrupted by a signal or error. If the call is  successful
       it will atomically decrement the semaphore value.

       After  SDL_SemWait() is successful, the semaphore can be released and its count atomically
       incremented by a successful call to SDL_SemPost.

RETURN VALUE

       Returns 0 if successful or -1 if there was an error (leaving the semaphore unchanged).

EXAMPLES

       if (SDL_SemWait(my_sem) == -1) {
               return WAIT_FAILED;
       }

       ...

       SDL_SemPost(my_sem);

SEE ALSO

       SDL_CreateSemaphore,     SDL_DestroySemaphore,     SDL_SemTryWait,     SDL_SemWaitTimeout,
       SDL_SemPost, SDL_SemValue