epoll_register_kevent
if (epoll_register_kevent(retval, epfd, fd, EVFILT_READ, 0) != ENOENT ||
epoll_register_kevent(retval, epfd, fd, EVFILT_WRITE, 0) != ENOENT)
error1 = epoll_register_kevent(retval, epfd, fd, EVFILT_READ,
error2 = epoll_register_kevent(retval, epfd, fd, EVFILT_WRITE,
static int epoll_register_kevent(register_t *, int, int, int,