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#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <sys/types.h>

#define MAXBUF 1024
/************关于本文档********************************************
*filename: async-server.c
*purpose: 演示网络异步通讯，这是服务器端程序
*wrote by: zhoulifa(zhoulifa@163.com) 周立发(http://zhoulifa.bokee.com)
Linux爱好者 Linux知识传播者 SOHO族 开发者 最擅长C语言
*date time:2007-01-25 21:22
*Note: 任何人可以任意复制代码并运用这些文档，当然包括你的商业用途
* 但请遵循GPL
*Thanks to: Google.com
*Hope:希望越来越多的人贡献自己的力量，为科学技术发展出力
* 科技站在巨人的肩膀上进步更快！感谢有开源前辈的贡献！
*********************************************************************/

int main(int argc, char **argv)
{
    int sockfd, new_fd;
    socklen_t len;
    struct sockaddr_in my_addr, their_addr;
    unsigned int myport, lisnum;
    char buf[MAXBUF + 1];
    fd_set rfds;
    struct timeval tv;
    int retval, maxfd = -1;

    if (argv[1])
        myport = atoi(argv[1]);
    else
        myport = 7838;

    if (argv[2])
        lisnum = atoi(argv[2]);
    else
        lisnum = 2;

    if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    }

    bzero(&my_addr, sizeof(my_addr));
    my_addr.sin_family = PF_INET;
    my_addr.sin_port = htons(myport);
    if (argv[3])
        my_addr.sin_addr.s_addr = inet_addr(argv[3]);
    else
        my_addr.sin_addr.s_addr = INADDR_ANY;

    if (bind(sockfd, (struct sockaddr *) &my_addr, sizeof(struct sockaddr))
        == -1) {
        perror("bind");
        exit(1);
    }

    if (listen(sockfd, lisnum) == -1) {
        perror("listen");
        exit(1);
    }

    while (1) {
        printf
            ("\n----等待新的连接到来开始新一轮聊天……\n");
        len = sizeof(struct sockaddr);
        if ((new_fd =
             accept(sockfd, (struct sockaddr *) &their_addr,
                    &len)) == -1) {
            perror("accept");
            exit(errno);
        } else
            printf("server: got connection from %s, port %d, socket %d\n",
                   inet_ntoa(their_addr.sin_addr),
                   ntohs(their_addr.sin_port), new_fd);

        /* 开始处理每个新连接上的数据收发 */
        printf
            ("\n准备就绪，可以开始聊天了……直接输入消息回车即可发信息给对方\n");
        while (1) {
            /* 把集合清空 */
            FD_ZERO(&rfds);
            /* 把标准输入句柄0加入到集合中 */
            FD_SET(0, &rfds);
            maxfd = 0;
            /* 把当前连接句柄new_fd加入到集合中 */
            FD_SET(new_fd, &rfds);
            if (new_fd > maxfd)
                maxfd = new_fd;
            /* 设置最大等待时间 */
            tv.tv_sec = 1;
            tv.tv_usec = 0;
            /* 开始等待 */
            retval = select(maxfd + 1, &rfds, NULL, NULL, &tv);
            if (retval == -1) {
                printf("将退出，select出错！ %s", strerror(errno));
                break;
            } else if (retval == 0) {
                /* printf
                   ("没有任何消息到来，用户也没有按键，继续等待……\n"); */
                continue;
            } else {
                if (FD_ISSET(0, &rfds)) {
                    /* 用户按键了，则读取用户输入的内容发送出去 */
                    bzero(buf, MAXBUF + 1);
                    fgets(buf, MAXBUF, stdin);
                    if (!strncasecmp(buf, "quit", 4)) {
                        printf("自己请求终止聊天！\n");
                        break;
                    }
                    len = send(new_fd, buf, strlen(buf) - 1, 0);
                    if (len > 0)
                        printf
                            ("消息:%s\t发送成功，共发送了%d个字节！\n",
                             buf, len);
                    else {
                        printf
                            ("消息'%s'发送失败！错误代码是%d，错误信息是'%s'\n",
                             buf, errno, strerror(errno));
                        break;
                    }
                }
                if (FD_ISSET(new_fd, &rfds)) {
                    /* 当前连接的socket上有消息到来则接收对方发过来的消息并显示 */
                    bzero(buf, MAXBUF + 1);
                    /* 接收客户端的消息 */
                    len = recv(new_fd, buf, MAXBUF, 0);
                    if (len > 0)
                        printf
                            ("接收消息成功:'%s'，共%d个字节的数据\n",
                             buf, len);
                    else {
                        if (len < 0)
                            printf
                                ("消息接收失败！错误代码是%d，错误信息是'%s'\n",
                                 errno, strerror(errno));
                        else
                            printf("对方退出了，聊天终止\n");
                        break;
                    }
                }
            }
        }
        close(new_fd);
        /* 处理每个新连接上的数据收发结束 */
        printf("还要和其它连接聊天吗？(no->退出)");
        fflush(stdout);
        bzero(buf, MAXBUF + 1);
        fgets(buf, MAXBUF, stdin);
        if (!strncasecmp(buf, "no", 2)) {
            printf("终止聊天！\n");
            break;
        }
    }

    close(sockfd);
    return 0;
}

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <resolv.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>

#define MAXBUF 1024
/************关于本文档********************************************
// *filename: ssync-client.c
*purpose: 演示网络异步通讯，这是客户端程序
*wrote by: zhoulifa(zhoulifa@163.com) 周立发(http://zhoulifa.bokee.com)
Linux爱好者 Linux知识传播者 SOHO族 开发者 最擅长C语言
*date time:2007-01-25 21:32
*Note: 任何人可以任意复制代码并运用这些文档，当然包括你的商业用途
* 但请遵循GPL
*Thanks to: Google.com
*Hope:希望越来越多的人贡献自己的力量，为科学技术发展出力
* 科技站在巨人的肩膀上进步更快！感谢有开源前辈的贡献！
*********************************************************************/
int main(int argc, char **argv)
{
    int sockfd, len;
    struct sockaddr_in dest;
    char buffer[MAXBUF + 1];
    fd_set rfds;
    struct timeval tv;
    int retval, maxfd = -1;

    if (argc != 3) {
        printf
            ("参数格式错误！正确用法如下：\n\t\t%s IP地址 端口\n\t比如:\t%s 127.0.0.1 80\n此程序用来从某个 IP 地址的服务器某个端口接收最多 MAXBUF 个字节的消息",
             argv[0], argv[0]);
        exit(0);
    }
    /* 创建一个 socket 用于 tcp 通信 */
    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        perror("Socket");
        exit(errno);
    }

    /* 初始化服务器端（对方）的地址和端口信息 */
    bzero(&dest, sizeof(dest));
    dest.sin_family = AF_INET;
    dest.sin_port = htons(atoi(argv[2]));
    if (inet_aton(argv[1], (struct in_addr *) &dest.sin_addr.s_addr) == 0) {
        perror(argv[1]);
        exit(errno);
    }

    /* 连接服务器 */
    if (connect(sockfd, (struct sockaddr *) &dest, sizeof(dest)) != 0) {
        perror("Connect ");
        exit(errno);
    }

    printf
        ("\n准备就绪，可以开始聊天了……直接输入消息回车即可发信息给对方\n");
    while (1) {
        /* 把集合清空 */
        FD_ZERO(&rfds);
        /* 把标准输入句柄0加入到集合中 */
        FD_SET(0, &rfds);
        maxfd = 0;
        /* 把当前连接句柄sockfd加入到集合中 */
        FD_SET(sockfd, &rfds);
        if (sockfd > maxfd)
            maxfd = sockfd;
        /* 设置最大等待时间 */
        tv.tv_sec = 1;
        tv.tv_usec = 0;
        /* 开始等待 */
        retval = select(maxfd + 1, &rfds, NULL, NULL, &tv);
        if (retval == -1) {
            printf("将退出，select出错！ %s", strerror(errno));
            break;
        } else if (retval == 0) {
            /* printf
               ("没有任何消息到来，用户也没有按键，继续等待……\n"); */
            continue;
        } else {
            if (FD_ISSET(sockfd, &rfds)) {
                /* 连接的socket上有消息到来则接收对方发过来的消息并显示 */
                bzero(buffer, MAXBUF + 1);
                /* 接收对方发过来的消息，最多接收 MAXBUF 个字节 */
                len = recv(sockfd, buffer, MAXBUF, 0);
                if (len > 0)
                    printf
                        ("接收消息成功:'%s'，共%d个字节的数据\n",
                         buffer, len);
                else {
                    if (len < 0)
                        printf
                            ("消息接收失败！错误代码是%d，错误信息是'%s'\n",
                             errno, strerror(errno));
                    else
                        printf("对方退出了，聊天终止！\n");
                    break;
                }
            }
            if (FD_ISSET(0, &rfds)) {
                /* 用户按键了，则读取用户输入的内容发送出去 */
                bzero(buffer, MAXBUF + 1);
                fgets(buffer, MAXBUF, stdin);
                if (!strncasecmp(buffer, "quit", 4)) {
                    printf("自己请求终止聊天！\n");
                    break;
                }
                /* 发消息给服务器 */
                len = send(sockfd, buffer, strlen(buffer) - 1, 0);
                if (len < 0) {
                    printf
                        ("消息'%s'发送失败！错误代码是%d，错误信息是'%s'\n",
                         buffer, errno, strerror(errno));
                    break;
                } else
                    printf
                        ("消息：%s\t发送成功，共发送了%d个字节！\n",
                         buffer, len);
            }
        }
    }
    /* 关闭连接 */
    close(sockfd);
    return 0;
}