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(3), SDL_DestroySemaphore(3), SDL_SemTryWait(3), SDL_SemWaitTimeout(3), SDL_SemPost(3), SDL_SemValue(3)

COPYRIGHT

This manual page is taken from the SDL library, licensed under GNU LGPL.