SDL_SemWait(3)
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