SDL_CreateSemaphore man page

SDL_CreateSemaphore — Creates a new semaphore and assigns an initial value to it.


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

SDL_sem *SDL_CreateSemaphore(Uint32 initial_value);


SDL_CreateSemaphore() creates a new semaphore and initializes it with the value initial_value. Each locking operation on the semaphore by SDL_SemWait, SDL_SemTryWait or SDL_SemWaitTimeout will atomically decrement the semaphore value. The locking operation will be blocked if the semaphore value is not positive (greater than zero). Each unlock operation by SDL_SemPost will atomically increment the semaphore value.

Return Value

Returns a pointer to an initialized semaphore or NULL if there was an error.


SDL_sem *my_sem;

my_sem = SDL_CreateSemaphore(INITIAL_SEM_VALUE);

if (my_sem == NULL) {
        return CREATE_SEM_FAILED;

See Also

SDL_DestroySemaphore, SDL_SemWait, SDL_SemTryWait, SDL_SemWaitTimeout, SDL_SemPost, SDL_SemValue


SDL SDL API Reference Tue 11 Sep 2001, 23:00