include <sys/epoll.h>

/* 创立一个epoll的句柄,size用来通知内核须要监听的数目一共有多大。当创立好epoll句柄后,
它就是会占用一个fd值,所以在应用完epoll后,必须调用close()敞开,否则可能导致fd被耗尽。*/
int epoll_create(int size);

/epoll的事件注册函数/
int epoll_ctl(int epfd, int op, int fd, struct epoll_event *event);

/期待事件的到来,如果检测到事件,就将所有就绪的事件从内核事件表中复制到它的第二个参数events指向的数组/
int epoll_wait(int epfd, struct epoll_event *events, int maxevents, int timeout);

struct epoll_event ev, *events;
for(;;) {

nfds = epoll_wait(kdpfd, events, maxevents, -1);for(n = 0; n < nfds; ++n) {    if(events[n].data.fd == listener) {        client = accept(listener, (struct sockaddr *) &local,                        &addrlen);        if(client < 0){            perror("accept");            continue;        }        setnonblocking(client);        ev.events = EPOLLIN | EPOLLET;        ev.data.fd = client;        if (epoll_ctl(kdpfd, EPOLL_CTL_ADD, client, &ev) < 0) {            fprintf(stderr, "epoll set insertion error: fd=%d0,                    client);            return -1;        }    }    else        do_use_fd(events[n].data.fd);}

}