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"SDL_SemWait" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference"
"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 created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00