POLLNVAL
FLAG_INFO_ENTRY(POLLNVAL),
{ "inv", POLLNVAL },
fds[i].events |= POLLNVAL | POLLERR | POLLHUP;
sync->set[i].events = POLLNVAL;
fds[i].revents = POLLNVAL;
if (fds[i].fd >= 0 && (sync->set[i].events & POLLNVAL) == 0)