After receiving a client event (EPOLLIN|EPOLLOUT|EPOLLRDHUP) ,then close the nonblock file descriptor (say it n), and get a errno ( n is busy).Because system is busy, almost at one time accept a new client, n will be reuse. Then next event of n will be (EPOLLIN|EPOLLERR|EPOLLHUP|EPOLLRDHUP).if recv it ,get a errno(Connection reset by peer(104)).
question about reusing a nonblock file descriptor for epoll