HelenOS sources

SYS_THREAD_USLEEP   66 kernel/generic/src/syscall/syscall.c 	[SYS_THREAD_USLEEP] = (syshandler_t) sys_thread_usleep,
SYS_THREAD_USLEEP   47 uspace/app/trace/syscalls.c 	[SYS_THREAD_USLEEP] = { "thread_usleep", 1, V_ERRNO },
SYS_THREAD_USLEEP  180 uspace/lib/c/generic/thread/thread.c 	(void) __SYSCALL1(SYS_THREAD_USLEEP, usec);