C++ (Cpp) dispatch_atomic_acquire_barrierの例

コード例 #1

ファイル: semaphore.c プロジェクト: PSPDFKit-labs/libdispatch

long
dispatch_semaphore_wait(dispatch_semaphore_t dsema, dispatch_time_t timeout)
{
	long value = dispatch_atomic_dec2o(dsema, dsema_value);
	dispatch_atomic_acquire_barrier();
	if (fastpath(value >= 0)) {
		return 0;
	}
	return _dispatch_semaphore_wait_slow(dsema, timeout);
}

コード例 #2

ファイル: apply.c プロジェクト: Rogaven/libdispatch

DISPATCH_NOINLINE
void
dispatch_apply_f(size_t iterations, dispatch_queue_t dq, void *ctxt,
		void (*func)(void *, size_t))
{
	if (slowpath(iterations == 0)) {
		return;
	}

	dispatch_apply_t da = (typeof(da))_dispatch_continuation_alloc();

	da->da_func = func;
	da->da_ctxt = ctxt;
	da->da_iterations = iterations;
	da->da_index = 0;
	da->da_thr_cnt = _dispatch_hw_config.cc_max_active;
	da->da_done = 0;
	da->da_queue = NULL;

	if (da->da_thr_cnt > DISPATCH_APPLY_MAX_CPUS) {
		da->da_thr_cnt = DISPATCH_APPLY_MAX_CPUS;
	}
	if (iterations < da->da_thr_cnt) {
		da->da_thr_cnt = (uint32_t)iterations;
	}
	if (slowpath(dq->dq_width <= 2) || slowpath(da->da_thr_cnt <= 1) ||
			slowpath(_dispatch_thread_getspecific(dispatch_apply_key))) {
		return dispatch_sync_f(dq, da, _dispatch_apply_serial);
	}
	dispatch_queue_t old_dq = (dispatch_queue_t)
			_dispatch_thread_getspecific(dispatch_queue_key);
	if (slowpath(dq->do_targetq)) {
		if (slowpath(dq == old_dq)) {
			return dispatch_sync_f(dq, da, _dispatch_apply_serial);
		} else {
			da->da_queue = dq;
			return dispatch_sync_f(dq, da, _dispatch_apply_redirect);
		}
	}
	dispatch_atomic_acquire_barrier();
	_dispatch_thread_setspecific(dispatch_queue_key, dq);
	_dispatch_apply_f2(dq, da, _dispatch_apply2);
	_dispatch_thread_setspecific(dispatch_queue_key, old_dq);
}