epoll简单回声服务器

条件触发

void server102()
{
    int serv_sock, clnt_sock;
    sockaddr_in serv_adr, clnt_adr;
    socklen_t clnt_sz ;
    char buf[1024]{};
    serv_sock = socket(PF_INET, SOCK_STREAM, 0);
    serv_adr.sin_family = AF_INET;
    serv_adr.sin_port = htons(9527);
    serv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
    int optval = 0;
    setsockopt(serv_sock, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(sockaddr_in));
    if (bind(serv_sock, (sockaddr*)&serv_adr, sizeof(sockaddr)) == -1) {
        printf("bind error %d %s\n", errno, strerror(errno));
        close(serv_sock);
        return;
    }
    if (listen(serv_sock, 5) == -1) {
        printf("listen error %d %s\n", errno, strerror(errno));
        close(serv_sock);
        return;
    }
    epoll_event event;
    int epfd, event_cnt;
    epfd = epoll_create(2048);
    if (epfd == -1) {
        printf("epoll_create error %d %s\n", errno, strerror(errno));
        close(serv_sock);
        return;
    }
    epoll_event* all_events = new epoll_event[100];

    event.events = EPOLLIN;
    event.data.fd = serv_sock;
    epoll_ctl(epfd, EPOLL_CTL_ADD, serv_sock, &event);
    while (true) {
        event_cnt = epoll_wait(epfd, all_events, 100, 1000);//all_events用来接收消息队列
        if (event_cnt == -1) {
            printf("epoll_wait error %d %s\n", errno, strerror(errno));
            break;
        }
        if (event_cnt == 0)continue;
        ;
        for (int i = 0; i < event_cnt; i++) {
            if (all_events[i].data.fd == serv_sock) {
                clnt_sz = sizeof(clnt_adr);
                clnt_sock = accept(serv_sock, (sockaddr*)&clnt_adr, &clnt_sz);
                event.events = EPOLLIN;
                event.data.fd = clnt_sock;
                epoll_ctl(epfd, EPOLL_CTL_ADD, clnt_sock, &event);
                printf("client is connected!%d\n", clnt_sock);
            }
            else {
                ssize_t len = read(all_events[i].data.fd, buf, sizeof(buf));
                if (len <= 0) {
                    epoll_ctl(epfd, EPOLL_CTL_DEL, all_events[i].data.fd, &all_events[i]);
                    close(all_events[i].data.fd);
                    printf("client is exeit!%d\n", clnt_sock);
                }
                else {
                    write(all_events[i].data.fd, buf, len);
                }
            }
        }        
    }
    delete[] all_events;
    close(serv_sock);
    close(epfd);
}

边缘触发

void server102()
{
    int serv_sock, clnt_sock;
    sockaddr_in serv_adr, clnt_adr;
    socklen_t clnt_sz ;
    char buf[5]{};
    serv_sock = socket(PF_INET, SOCK_STREAM, 0);
    serv_adr.sin_family = AF_INET;
    serv_adr.sin_port = htons(9527);
    serv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
    int optval = 0;
    setsockopt(serv_sock, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(sockaddr_in));
    if (bind(serv_sock, (sockaddr*)&serv_adr, sizeof(sockaddr)) == -1) {
        printf("bind error %d %s\n", errno, strerror(errno));
        close(serv_sock);
        return;
    }
    if (listen(serv_sock, 5) == -1) {
        printf("listen error %d %s\n", errno, strerror(errno));
        close(serv_sock);
        return;
    }
    epoll_event event;
    int epfd, event_cnt;
    epfd = epoll_create(2048);
    if (epfd == -1) {
        printf("epoll_create error %d %s\n", errno, strerror(errno));
        close(serv_sock);
        return;
    }
    epoll_event* all_events = new epoll_event[100];
    event.events = EPOLLIN;
    event.data.fd = serv_sock;
    epoll_ctl(epfd, EPOLL_CTL_ADD, serv_sock, &event);
    while (true) {
        event_cnt = epoll_wait(epfd, all_events, 100, 1);//all_events用来接收消息队列
        if (event_cnt == -1) {
            printf("epoll_wait error %d %s\n", errno, strerror(errno));
            break;
        }
        if (event_cnt == 0)continue;
        ;
        for (int i = 0; i < event_cnt; i++) {
            if (all_events[i].data.fd == serv_sock) {
                clnt_sz = sizeof(clnt_adr);
                clnt_sock = accept(serv_sock, (sockaddr*)&clnt_adr, &clnt_sz);
                event.events = EPOLLIN|EPOLLET;//EPOLLET启动边缘触发
                event.data.fd = clnt_sock;
                int flag = fcntl(clnt_sock, F_GETFL, 0);//获取连接客户端的状态
                fcntl(clnt_sock, F_SETFL, flag | O_NONBLOCK);//将连接客户端设置为非阻塞状态,适合于大文件多次收发
                epoll_ctl(epfd, EPOLL_CTL_ADD, clnt_sock, &event);
                printf("client is connected!%d\n", clnt_sock);
            }
            else {
                while (true) {//循环读
                    ssize_t len = read(all_events[i].data.fd, buf, sizeof(buf));
                    if (len < 0) {
                        if (errno == EAGAIN)//表示已经读完了
                            break;
                        printf("epoll_wait error %d %s\n", errno, strerror(errno));
                    }
                    if (len == 0) {
                        epoll_ctl(epfd, EPOLL_CTL_DEL, all_events[i].data.fd, &all_events[i]);
                        close(all_events[i].data.fd);
                        printf("client is exeit!%d\n", clnt_sock);
                        break;
                    }
                    else {
                        printf("%s(%d):%s \n", __FILE__, __LINE__, __FUNCTION__);
                        write(all_events[i].data.fd, buf, len);
                    }
                }
            }
        }
        printf("%s(%d):%s \n", __FILE__, __LINE__, __FUNCTION__);
    }
    delete[] all_events;
    close(serv_sock);
    close(epfd);
}