SDL_CreateSemaphore

Section: SDL API Reference (3)
Updated: Tue 11 Sep 2001, 23:00
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NAME

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

SYNOPSIS

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

SDL_sem *SDL_CreateSemaphore(Uint32 initial_value);

DESCRIPTION

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.

EXAMPLES

SDL_sem *my_sem;

my_sem = SDL_CreateSemaphore(INITIAL_SEM_VALUE);

if (my_sem == NULL) {
        return CREATE_SEM_FAILED;
}