HelenOS sources

futex_down_timeout  209 uspace/lib/c/generic/private/futex.h 	return futex_down_timeout(futex, &tv) == EOK;
futex_down_timeout  223 uspace/lib/c/generic/private/futex.h 	return futex_down_timeout(futex, NULL);
futex_down_timeout  132 uspace/lib/c/generic/thread/fibril.c 		return futex_down_timeout(&ready_semaphore, expires);
HelenOS homepage, sources at GitHub