UMTX_OP_MUTEX_LOCK
ret = _umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0,
return (_umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, 0));
return (_umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, 0));
[UMTX_OP_MUTEX_LOCK] = __umtx_op_lock_umutex,