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linux：C++的socket编程

　　基本的局域网聊天

　　局域网聊天TCP服务端：

#include <sys/types.h>

#include <sys/socket.h>

#include <stdio.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <string.h>

#include <stdlib.h>

#include <fcntl.h>

#include <sys/shm.h>

#include <thread>

#include <iostream>

#define PORT 7000

#define QUEUE 20

int conn;

void thread_task() {

}

int main() {

    //printf("%d\n",AF_INET);

    //printf("%d\n",SOCK_STREAM);

    int ss = socket(AF_INET, SOCK_STREAM, );

    //printf("%d\n",ss);

    struct sockaddr_in server_sockaddr;

    server_sockaddr.sin_family = AF_INET;

    server_sockaddr.sin_port = htons(PORT);

    //printf("%d\n",INADDR_ANY);

    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    if(bind(ss, (struct sockaddr* ) &server_sockaddr, sizeof(server_sockaddr))==-) {

        perror("bind");

        exit();

    }

    if(listen(ss, QUEUE) == -) {

        perror("listen");

        exit();

    }

    struct sockaddr_in client_addr;

    socklen_t length = sizeof(client_addr);

    ///成功返回非负描述字，出错返回-1

    conn = accept(ss, (struct sockaddr*)&client_addr, &length);

    if( conn <  ) {

        perror("connect");

        exit();

    }

    char buffer[];

    //创建另外一个线程

    //std::thread t(thread_task);

    //t.join();

    //char buf[1024];

    //主线程

    while() {

        // memset(buf, 0 ,sizeof(buf));

        // if(fgets(buf, sizeof(buf),stdin) != NULL) {

        //     send(conn, buf, sizeof(buf), 0);

        // }

        memset(buffer,  ,sizeof(buffer));

        int len = recv(conn, buffer, sizeof(buffer), );

        if(strcmp(buffer, "exit\n") == ) break;

        printf("%s", buffer);

        //必须要有返回数据， 这样才算一个完整的请求

        send(conn, buffer, len , );

    }

    close(conn);

    close(ss);

    return ;

}

　　局域网聊天TCP客户端：

#include <sys/types.h>

#include <sys/socket.h>

#include <stdio.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <string.h>

#include <stdlib.h>

#include <fcntl.h>

#include <sys/shm.h>

#define MYPORT  7000

#define BUFFER_SIZE 1024

int main()

{

    ///定义sockfd

    int sock_cli = socket(AF_INET,SOCK_STREAM, );

    ///定义sockaddr_in

    struct sockaddr_in servaddr;

    memset(&servaddr, , sizeof(servaddr));

    servaddr.sin_family = AF_INET;

    servaddr.sin_port = htons(MYPORT);  ///服务器端口

    servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");  ///服务器ip

    //连接服务器，成功返回0，错误返回-1

    if (connect(sock_cli, (struct sockaddr *)&servaddr, sizeof(servaddr)) < )

    {

        perror("connect");

        exit();

    }

    char sendbuf[BUFFER_SIZE];

    char recvbuf[BUFFER_SIZE];

    while (fgets(sendbuf, sizeof(sendbuf), stdin) != NULL)

    {

        send(sock_cli, sendbuf, strlen(sendbuf),); ///发送

        if(strcmp(sendbuf,"exit\n")==)

            break;

        recv(sock_cli, recvbuf, sizeof(recvbuf),); ///接收

        fputs(recvbuf, stdout);

        memset(sendbuf, , sizeof(sendbuf));

        memset(recvbuf, , sizeof(recvbuf));

    }

    close(sock_cli);

    return ;

}

　　

　　客户端服务端双向异步聊天源码

　　以上的局域网聊天应用有一个很重要的缺点， 服务器只能显示客户端发送的消息， 却无法给客户端发送消息， 这个很尴尬；

　　通过使用C中的select()函数， 实现一个异步聊天工具：

　　异步聊天服务端代码：

#include <sys/types.h>

#include <sys/socket.h>

#include <stdio.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <string.h>

#include <stdlib.h>

#include <fcntl.h>

#include <sys/shm.h>

#include <iostream>

#define PORT 7000

#define QUEUE 20

int main() {

    fd_set rfds;

    struct timeval tv;

    int retval, maxfd;

    int ss = socket(AF_INET, SOCK_STREAM, );

    struct sockaddr_in server_sockaddr;

    server_sockaddr.sin_family = AF_INET;

    server_sockaddr.sin_port = htons(PORT);

    //printf("%d\n",INADDR_ANY);

    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    if(bind(ss, (struct sockaddr* ) &server_sockaddr, sizeof(server_sockaddr))==-) {

        perror("bind");

        exit();

    }

    if(listen(ss, QUEUE) == -) {

        perror("listen");

        exit();

    }

    struct sockaddr_in client_addr;

    socklen_t length = sizeof(client_addr);

    ///成功返回非负描述字，出错返回-1

    int conn = accept(ss, (struct sockaddr*)&client_addr, &length);

    if( conn <  ) {

        perror("connect");

        exit();

    }

    while() {

        /*把可读文件描述符的集合清空*/

        FD_ZERO(&rfds);

        /*把标准输入的文件描述符加入到集合中*/

        FD_SET(, &rfds);

        maxfd = ;

        /*把当前连接的文件描述符加入到集合中*/

        FD_SET(conn, &rfds);

        /*找出文件描述符集合中最大的文件描述符*/

        if(maxfd < conn)

            maxfd = conn;

        /*设置超时时间*/

        tv.tv_sec = ;

        tv.tv_usec = ;

        /*等待聊天*/

        retval = select(maxfd+, &rfds, NULL, NULL, &tv);

        if(retval == -){

            printf("select出错，客户端程序退出\n");

            break;

        }else if(retval == ){

            printf("服务端没有任何输入信息，并且客户端也没有信息到来，waiting...\n");

            continue;

        }else{

            /*客户端发来了消息*/

            if(FD_ISSET(conn,&rfds)){

                char buffer[];

                memset(buffer,  ,sizeof(buffer));

                int len = recv(conn, buffer, sizeof(buffer), );

                if(strcmp(buffer, "exit\n") == ) break;

                printf("%s", buffer);

                //send(conn, buffer, len , 0);把数据回发给客户端

            }

            /*用户输入信息了,开始处理信息并发送*/

            if(FD_ISSET(, &rfds)){

                char buf[];

                fgets(buf, sizeof(buf), stdin);

                //printf("you are send %s", buf);

                send(conn, buf, sizeof(buf), );

            }

        }

    }

    close(conn);

    close(ss);

    return ;

}

　　异步聊天客户端代码：

#include <sys/types.h>

#include <sys/socket.h>

#include <stdio.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <string.h>

#include <stdlib.h>

#include <fcntl.h>

#include <sys/shm.h>

#define MYPORT  7000

#define BUFFER_SIZE 1024

int main()

{

    int sock_cli;

    fd_set rfds;

    struct timeval tv;

    int retval, maxfd;

    ///定义sockfd

    sock_cli = socket(AF_INET,SOCK_STREAM, );

    ///定义sockaddr_in

    struct sockaddr_in servaddr;

    memset(&servaddr, , sizeof(servaddr));

    servaddr.sin_family = AF_INET;

    servaddr.sin_port = htons(MYPORT);  ///服务器端口

    servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");  ///服务器ip

    //连接服务器，成功返回0，错误返回-1

    if (connect(sock_cli, (struct sockaddr *)&servaddr, sizeof(servaddr)) < )

    {

        perror("connect");

        exit();

    }

    while(){

        /*把可读文件描述符的集合清空*/

        FD_ZERO(&rfds);

        /*把标准输入的文件描述符加入到集合中*/

        FD_SET(, &rfds);

        maxfd = ;

        /*把当前连接的文件描述符加入到集合中*/

        FD_SET(sock_cli, &rfds);

        /*找出文件描述符集合中最大的文件描述符*/

        if(maxfd < sock_cli)

            maxfd = sock_cli;

        /*设置超时时间*/

        tv.tv_sec = ;

        tv.tv_usec = ;

        /*等待聊天*/

        retval = select(maxfd+, &rfds, NULL, NULL, &tv);

        if(retval == -){

            printf("select出错，客户端程序退出\n");

            break;

        }else if(retval == ){

            printf("客户端没有任何输入信息，并且服务器也没有信息到来，waiting...\n");

            continue;

        }else{

            /*服务器发来了消息*/

            if(FD_ISSET(sock_cli,&rfds)){

                char recvbuf[BUFFER_SIZE];

                int len;

                len = recv(sock_cli, recvbuf, sizeof(recvbuf),);

                printf("%s", recvbuf);

                memset(recvbuf, , sizeof(recvbuf));

            }

            /*用户输入信息了,开始处理信息并发送*/

            if(FD_ISSET(, &rfds)){

                char sendbuf[BUFFER_SIZE];

                fgets(sendbuf, sizeof(sendbuf), stdin);

                send(sock_cli, sendbuf, strlen(sendbuf),); //发送

                memset(sendbuf, , sizeof(sendbuf));

            }

        }

    }

    close(sock_cli);

    return ;

}

　　局域网内服务端和有限个客户端聊天源码

　　以上的局域网聊天只能支持一个用户， 我们还要改改， 必须是支持多用户的聊天室：

　　局域网TCP多人聊天服务端代码：

#include <sys/types.h>

#include <sys/socket.h>

#include <stdio.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <string.h>

#include <stdlib.h>

#include <fcntl.h>

#include <sys/shm.h>

#include <iostream>

#include <thread>

#define PORT 7000

#define QUEUE 20

int ss;

struct sockaddr_in client_addr;

socklen_t length = sizeof(client_addr);

int conns[] = {};

int z = ;

void thread_fn() {

    //成功返回非负描述字，出错返回-1

    int conn = accept(ss, (struct sockaddr*)&client_addr, &length);

    if( conn <  ) {

        perror("connect");

        exit();

    }

    //把连接保存到临时数组中;

    conns[z] = conn;

    z++;

    fd_set rfds;

    struct timeval tv;

    int retval, maxfd;

    while() {

        /*把可读文件描述符的集合清空*/

        FD_ZERO(&rfds);

        /*把标准输入的文件描述符加入到集合中*/

        FD_SET(, &rfds);

        maxfd = ;

        /*把当前连接的文件描述符加入到集合中*/

        FD_SET(conn, &rfds);

        /*找出文件描述符集合中最大的文件描述符*/

        if(maxfd < conn)

            maxfd = conn;

        /*设置超时时间*/

        tv.tv_sec = ;

        tv.tv_usec = ;

        /*等待聊天*/

        retval = select(maxfd+, &rfds, NULL, NULL, &tv);

        if(retval == -){

            printf("select出错，客户端程序退出\n");

            break;

        }else if(retval == ){

            printf("服务端没有任何输入信息，并且客户端也没有信息到来，waiting...\n");

            continue;

        }else{

            /*客户端发来了消息*/

            if(FD_ISSET(conn,&rfds)){

                char buffer[];

                memset(buffer,  ,sizeof(buffer));

                int len = recv(conn, buffer, sizeof(buffer), );

                if(strcmp(buffer, "exit\n") == ) break;

                printf("%s", buffer);

                //send(conn, buffer, len , 0);把数据回发给客户端

            }

            /*用户输入信息了,开始处理信息并发送*/

            if(FD_ISSET(, &rfds)){

                char buf[];

                fgets(buf, sizeof(buf), stdin);

                //printf("you are send %s", buf);

                for(int i=; i<z; i++) {

                    send(conns[i], buf, sizeof(buf), );

                }

            }

        }

    }

    close(conn);

}

void thread_select(int conn) {

}

int main() {

    ss = socket(AF_INET, SOCK_STREAM, );

    struct sockaddr_in server_sockaddr;

    server_sockaddr.sin_family = AF_INET;

    server_sockaddr.sin_port = htons(PORT);

    //printf("%d\n",INADDR_ANY);

    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    if(bind(ss, (struct sockaddr* ) &server_sockaddr, sizeof(server_sockaddr))==-) {

        perror("bind");

        exit();

    }

    if(listen(ss, QUEUE) == -) {

        perror("listen");

        exit();

    }

    std::thread t(thread_fn);

    std::thread t1(thread_fn);

    t.join();

    t1.join();

    close(ss);

    return ;

}

　　局域网TCP多人聊天客户端代码：

#include <sys/types.h>

#include <sys/socket.h>

#include <stdio.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <string.h>

#include <stdlib.h>

#include <fcntl.h>

#include <sys/shm.h>

#define MYPORT  7000

#define BUFFER_SIZE 1024

int main()

{

    int sock_cli;

    fd_set rfds;

    struct timeval tv;

    int retval, maxfd;

    ///定义sockfd

    sock_cli = socket(AF_INET,SOCK_STREAM, );

    ///定义sockaddr_in

    struct sockaddr_in servaddr;

    memset(&servaddr, , sizeof(servaddr));

    servaddr.sin_family = AF_INET;

    servaddr.sin_port = htons(MYPORT);  ///服务器端口

    servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");  ///服务器ip

    //连接服务器，成功返回0，错误返回-1

    if (connect(sock_cli, (struct sockaddr *)&servaddr, sizeof(servaddr)) < )

    {

        perror("connect");

        exit();

    }

    while(){

        /*把可读文件描述符的集合清空*/

        FD_ZERO(&rfds);

        /*把标准输入的文件描述符加入到集合中*/

        FD_SET(, &rfds);

        maxfd = ;

        /*把当前连接的文件描述符加入到集合中*/

        FD_SET(sock_cli, &rfds);

        /*找出文件描述符集合中最大的文件描述符*/

        if(maxfd < sock_cli)

            maxfd = sock_cli;

        /*设置超时时间*/

        tv.tv_sec = ;

        tv.tv_usec = ;

        /*等待聊天*/

        retval = select(maxfd+, &rfds, NULL, NULL, &tv);

        if(retval == -){

            printf("select出错，客户端程序退出\n");

            break;

        }else if(retval == ){

            printf("客户端没有任何输入信息，并且服务器也没有信息到来，waiting...\n");

            continue;

        }else{

            /*服务器发来了消息*/

            if(FD_ISSET(sock_cli,&rfds)){

                char recvbuf[BUFFER_SIZE];

                int len;

                len = recv(sock_cli, recvbuf, sizeof(recvbuf),);

                printf("%s", recvbuf);

                memset(recvbuf, , sizeof(recvbuf));

            }

            /*用户输入信息了,开始处理信息并发送*/

            if(FD_ISSET(, &rfds)){

                char sendbuf[BUFFER_SIZE];

                fgets(sendbuf, sizeof(sendbuf), stdin);

                send(sock_cli, sendbuf, strlen(sendbuf),); //发送

                memset(sendbuf, , sizeof(sendbuf));

            }

        }

    }

    close(sock_cli);

    return ;

}

　　完美异步聊天服务端和客户端源码

　　以上的多客户聊天不是很好， 因为只允许两个客户端连接， 体验非常差， 如果支持无限个客户端聊天的话那该多好啊， 哈哈， 这个也是可以的， 我们只要使用c＋＋的list即可， 它是可以自增的数组(其实算是链表)， 引用 头文件<list>即可：

　　无限个客户聊天的 服务端代码：

#include <sys/types.h>

#include <sys/socket.h>

#include <stdio.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <string.h>

#include <stdlib.h>

#include <fcntl.h>

#include <sys/shm.h>

#include <iostream>

#include <thread>

#include <list>

#define PORT 7000

#define IP "127.0.0.1"

int s;

struct sockaddr_in servaddr;

socklen_t len;

std::list<int> li;

void getConn() {

    while(){

        int conn = accept(s, (struct sockaddr*)&servaddr, &len);

        li.push_back(conn);

        printf("%d\n", conn);

    }

}

void getData() {

    struct timeval tv;

    tv.tv_sec = ;

    tv.tv_usec = ;

    while() {

        std::list<int>::iterator it;

        for(it=li.begin(); it!=li.end(); ++it){

            fd_set rfds;

            FD_ZERO(&rfds);

            int maxfd = ;

            int retval = ;

            FD_SET(*it, &rfds);

            if(maxfd < *it){

                maxfd = *it;

            }

            retval = select(maxfd+, &rfds, NULL, NULL, &tv);

            if(retval == -){

                printf("select error\n");

            }else if(retval == ) {

                //printf("not message\n");

            }else{

                char buf[];

                memset(buf,  ,sizeof(buf));

                int len = recv(*it, buf, sizeof(buf), );

                printf("%s", buf);

            }

        }

        sleep();

    }

}

void sendMess() {

    while() {

        char buf[];

        fgets(buf, sizeof(buf), stdin);

        //printf("you are send %s", buf);

        std::list<int>::iterator it;

        for(it=li.begin(); it!=li.end(); ++it){

            send(*it, buf, sizeof(buf), );

        }

    }

}

int main() {

    //new socket

    s = socket(AF_INET, SOCK_STREAM, );

    memset(&servaddr, , sizeof(servaddr));

    servaddr.sin_family = AF_INET;

    servaddr.sin_port = htons(PORT);

    servaddr.sin_addr.s_addr = inet_addr(IP);

    if(bind(s, (struct sockaddr* ) &servaddr, sizeof(servaddr))==-) {

        perror("bind");

        exit();

    }

    if(listen(s, ) == -) {

        perror("listen");

        exit();

    }

    len = sizeof(servaddr);

    //thread : while ==>> accpet

    std::thread t(getConn);

    t.detach();

    //printf("done\n");

    //thread : input ==>> send

    std::thread t1(sendMess);

    t1.detach();

    //thread : recv ==>> show

    std::thread t2(getData);

    t2.detach();

    while(){

    }

    return ;

}

　　无限个客户端连接的客户端代码：

#include <sys/types.h>

#include <sys/socket.h>

#include <stdio.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <string.h>

#include <stdlib.h>

#include <fcntl.h>

#include <sys/shm.h>

#define MYPORT  7000

#define BUFFER_SIZE 1024

int main()

{

    int sock_cli;

    fd_set rfds;

    struct timeval tv;

    int retval, maxfd;

    ///定义sockfd

    sock_cli = socket(AF_INET,SOCK_STREAM, );

    ///定义sockaddr_in

    struct sockaddr_in servaddr;

    memset(&servaddr, , sizeof(servaddr));

    servaddr.sin_family = AF_INET;

    servaddr.sin_port = htons(MYPORT);  ///服务器端口

    servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");  ///服务器ip

    //连接服务器，成功返回0，错误返回-1

    if (connect(sock_cli, (struct sockaddr *)&servaddr, sizeof(servaddr)) < )

    {

        perror("connect");

        exit();

    }

    while(){

        /*把可读文件描述符的集合清空*/

        FD_ZERO(&rfds);

        /*把标准输入的文件描述符加入到集合中*/

        FD_SET(, &rfds);

        maxfd = ;

        /*把当前连接的文件描述符加入到集合中*/

        FD_SET(sock_cli, &rfds);

        /*找出文件描述符集合中最大的文件描述符*/

        if(maxfd < sock_cli)

            maxfd = sock_cli;

        /*设置超时时间*/

        tv.tv_sec = ;

        tv.tv_usec = ;

        /*等待聊天*/

        retval = select(maxfd+, &rfds, NULL, NULL, &tv);

        if(retval == -){

            printf("select出错，客户端程序退出\n");

            break;

        }else if(retval == ){

            printf("客户端没有任何输入信息，并且服务器也没有信息到来，waiting...\n");

            continue;

        }else{

            /*服务器发来了消息*/

            if(FD_ISSET(sock_cli,&rfds)){

                char recvbuf[BUFFER_SIZE];

                int len;

                len = recv(sock_cli, recvbuf, sizeof(recvbuf),);

                printf("%s", recvbuf);

                memset(recvbuf, , sizeof(recvbuf));

            }

            /*用户输入信息了,开始处理信息并发送*/

            if(FD_ISSET(, &rfds)){

                char sendbuf[BUFFER_SIZE];

                fgets(sendbuf, sizeof(sendbuf), stdin);

                send(sock_cli, sendbuf, strlen(sendbuf),); //发送

                memset(sendbuf, , sizeof(sendbuf));

            }

        }

    }

    close(sock_cli);

    return ;

}

　　局域网通过UDP实现服务端和客户端的通信， UDP的服务端不需要执行listen函数和accept函数：

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <string.h>

#include <fcntl.h>

#include <stdio.h>

#include <unistd.h>

#define PORT_SERV 8888

#define BUFF_LEN 256

void udpserv_echo(int s, struct sockaddr* client);

int main() {

    int s;

    struct sockaddr_in addr_serv, addr_clie;

    s = socket(AF_INET, SOCK_DGRAM, );

    memset(&addr_serv,  , sizeof(addr_serv));

    addr_serv.sin_family = AF_INET;

    addr_serv.sin_addr.s_addr = htonl(INADDR_ANY);

    addr_serv.sin_port = htons(PORT_SERV);

    bind(s, (struct sockaddr*)&addr_serv, sizeof(addr_serv));

    udpserv_echo(s, (struct sockaddr*)&addr_clie);

    return ;

}

void udpserv_echo(int s, struct sockaddr* client) {

    int n;

    char buff[BUFF_LEN];

    int len;

    //printf("%p\n",&recvfrom);

    while() {

        socklen_t length = sizeof(client);

        n = recvfrom(s, buff, BUFF_LEN,  , client, &length);

        printf("%s\n", buff);

        //strcpy(buff, "nice to see you");

        sendto(s, buff, n, , client, len);

    }

}

　　UDP客户端代码， UDP客户端不需要connect函数， 但是执行sendto的时候需要指定 sockfd描述符：

#include <netinet/in.h>

#include <string.h>

#include <fcntl.h>

#include <stdio.h>

#include <unistd.h>

#include <arpa/inet.h>

#define PORT_SERV 8888

#define BUFF_LEN 256

void udpclient_echo(int s, struct sockaddr* serv) {

    char buff[BUFF_LEN];

    int len = sizeof(*serv);

    while(fgets(buff, BUFF_LEN, stdin)!=NULL) {

        sendto(s, buff, BUFF_LEN, , serv, len);

    }

}

int main(int argc , char ** argv) {

    int s;

    struct sockaddr_in addr_serv;

    s = socket(AF_INET, SOCK_DGRAM, );

    memset(&addr_serv,  , sizeof(addr_serv));

    addr_serv.sin_family = AF_INET;

    //addr_serv.sin_addr.s_addr = htonl(INADDR_ANY);

    addr_serv.sin_addr.s_addr = inet_addr(argv[]);

    addr_serv.sin_port = htons(PORT_SERV);

    udpclient_echo(s, (struct sockaddr*)&addr_serv);

    return ;

}

　　获取当前进程的ID：

#include <sys/types.h>

#include <unistd.h>

#include <stdio.h>

int main(void) {

    pid_t pid,ppid;

    pid = getpid();

    ppid = getppid();

    printf("pid is %d;\nppid is %d; \n",pid, ppid);

    return ;

}

　　system语句的使用：

#include <stdlib.h>

#include <stdio.h>

int main(void) {

    int ret;

    ret = system("ping www.baidu.com");

    printf("%d\n", ret);

    return ;

}

　　C++定时器

　　定时器， 这个是c++的语法， c的标准库中没有定时器：

#include <stdio.h>        //printf()

#include <unistd.h>        //pause()

#include <signal.h>        //signal()

#include <string.h>        //memset()

#include <sys/time.h>    //struct itimerval, setitimer()

static int count = ;

void printMes(int signo)

{

    printf("Get a SIGALRM, %d counts!\n", ++count);

}

int main()

{

    int res = ;

    struct itimerval tick;

    signal(SIGALRM, printMes);

    memset(&tick, , sizeof(tick));

    //Timeout to run first time

    tick.it_value.tv_sec = ;

    tick.it_value.tv_usec = ;

    //After first, the Interval time for clock

    tick.it_interval.tv_sec = ;

    tick.it_interval.tv_usec = ;

    setitimer(ITIMER_REAL, &tick, NULL);

    //if(setitimer(ITIMER_REAL, &tick, NULL) < 0)

            //printf("Set timer failed!\n");

    //When get a SIGALRM, the main process will enter another loop for pause()

    while()

    {

    }

    return ;

} 

　　select的使用，通过select可以实现定时器：

static void sleep_ms(unsigned int secs){

    struct timeval tval;

    tval.tv_sec=secs/;

    tval.tv_usec=(secs*)%;

    select(,NULL,NULL,NULL,&tval);

}

　　select异步代码

　　通过select，实现socket可读或者可写的时候，然后再搞事情：

#include <stdio.h>

#include <sys/time.h>

#include <sys/types.h>

#include <unistd.h>

int main() {

    while() {

        fd_set rd;

        struct timeval tv;

        int err;

        FD_ZERO(&rd);

        FD_SET(, &rd);

        tv.tv_sec = ;

        tv.tv_usec = ;

        err = select(, &rd, NULL, NULL, &tv);

        if(err == -) {

            perror("select error()\n");

        }else if(err == ) {

            printf("no data is avaliable now\n");

        }else{

            if(FD_ISSET(, &rd)) {

                char buf[];

                fgets(buf, sizeof(buf), stdin);

                printf("%s",buf);

            }

        }

    }

    return ;

}

　　pthead多线程

　　没有参数的多线程 ，假设文件名字为：ph.c ，那么要通过 gcc ph.c -o ph -w -lphread ，进行编译：

#include <stdio.h>

#include <string.h>

#include <pthread.h>

void *pfn() {

    printf("run\n");

}

void main(int argc , char *argv[] ) {

    pthread_t pid, pid2;

    pthread_create(&pid, NULL, pfn, NULL);

    pthread_join(pid, NULL);

}

　　pthead多线程编程， 使用pthead实现子程， 并给子程传递参数：

#include <stdio.h>

#include <pthread.h>

#include <unistd.h>

#include <string.h>

#include <stdlib.h>

#include <iostream>

void* start(void* args) {

    printf("sub thread ; the args is %d\n", *((int *)args));

    return NULL;

}

int main(void) {

    pthread_t pt;

    int ret = -;

    int times = ;

    int run = ;

    ret = pthread_create(&pt, NULL, start, &run);

    if(ret != ) {

        printf("create error\n");

        return ;

    }

    usleep();

    printf("main thread\n");

    pthread_join(pt, NULL);

    return ;

}

　　获取指定网卡的MAC地址和IP：

#include <net/ethernet.h>

#include <stdio.h>

#include <sys/socket.h>

#include <linux/if_packet.h>

#include <net/if.h>

#include <stdlib.h>

#include <string.h>

#include <fcntl.h>

#include <unistd.h>

#include <sys/ioctl.h>

#include <netinet/ether.h>

#include <netinet/in.h>

#include <arpa/inet.h>

void getMac(char *MAC, char *str) {

   char ifPath[]="/sys/class/net/"; //默认网卡路径

    strcat(ifPath , str);

    strcat(ifPath ,"/address");

    //打开这个设备

    FILE *ff = fopen(ifPath,"r");

    fread(MAC,, , ff);

    fclose(ff);

}

//根据网卡获取ip的通用函数

void getIp(unsigned char *ip, char *itf) {

    int fd;

    struct ifreq ifr;

    in_addr tIP ;

    fd = socket(AF_INET, SOCK_DGRAM, );    //using ioctl get IP address

    ifr.ifr_addr.sa_family = AF_INET;

    strcpy(ifr.ifr_name , (char*)itf);

    ioctl(fd, SIOCGIFADDR, &ifr);

    close(fd);

    tIP =((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr;

    memcpy((char*)ip , &tIP ,sizeof(in_addr));

    printf("ip is %s", inet_ntoa(tIP));

}

int main(int argc, char *argv[]) {

    struct sockaddr_ll device;

    char NetInterface[];

    strcpy(NetInterface, argv[]);

    int index = if_nametoindex ((const char*)NetInterface);

    printf("index is %d\n", index);

    //get MAC， 要设置初始值

    char MAC[]={};

    char end[] = "";

    getMac(MAC, argv[]);

    printf("%s\n", MAC);

    unsigned char ip[];

    getIp(ip, argv[]);

    printf("\n");

    return ;

}

　　C， fork语句的使用， fork返回值为0时说明运行在拷贝线程中：

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/types.h>

int main() {

    pid_t pid;

    pid = fork();

    if( - == pid ) {

        printf("error \n");

    }else if( pid == ) {

        printf(" fork value %d ; parent id : %d ; fork id : %d\n ", pid, getppid(), getpid());

    }else{

        printf(" run in parent scope, pid is %d \n", getpid());

    }

    return ;

}

　　通过使用fork，可以简化服务端的代码， 局域网聊天服务端代码：

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/socket.h>

#include <sys/types.h>

#include <unistd.h>

#include <errno.h>

#include <netinet/in.h>

#include <netdb.h>

#include <arpa/inet.h>

const int MAX_LINE = ;

const int PORT = ;

const int BACKLOG = ;

const int LISTENQ = ;

const int MAX_CONNECT = ;

int main() {

    struct sockaddr_in serAddr, cliAddr;

    int listenFd, connFd;

    pid_t childPid;

    char buf[MAX_LINE];

    socklen_t client;

    listenFd = socket(AF_INET, SOCK_STREAM, );

    if(listenFd < ){

        perror("socket error");

        exit();

    }

    bzero(&serAddr, sizeof(serAddr));

    serAddr.sin_family = AF_INET;

    serAddr.sin_addr.s_addr = htonl(INADDR_ANY);

    serAddr.sin_port = htons(PORT);

    if(bind(listenFd, (struct sockaddr*)&serAddr, sizeof(serAddr)) < ) {

        perror("bind error");

        exit();

    };

    if(listen(listenFd, LISTENQ) < ) {

        perror("listen error");

        exit();

    };

        printf("data");

    while(true) {

        client = sizeof(cliAddr);

        connFd = accept(listenFd, (struct sockaddr*)&cliAddr, &client);

        if(connFd < ) {

            perror("accept error");

            exit();

        }

        childPid =fork();

        if(childPid == ) {

            close(listenFd);

            char buf[MAX_LINE];

            while(read(connFd, buf, MAX_LINE) > ) {

                printf("data is %s", buf);

                memset(buf,  ,sizeof(buf));

            };

        }

    }

    close(listenFd);

    return ;

}

　　客户端代码：

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/socket.h>

#include <sys/types.h>

#include <unistd.h>

#include <errno.h>

#include <netinet/in.h>

#include <netdb.h>

#include <arpa/inet.h>

const int MAX_LINE = ;

const int PORT = ;

const int BACKLOG = ;

const int LISTENQ = ;

const int MAX_CONNECT = ;

int main(int argc , char **argv) {

    int sockFd;

    struct sockaddr_in serAddr;

    if( argc != ) {

        perror("args error");

        exit();

    }

    sockFd = socket(AF_INET, SOCK_STREAM, );

    if(sockFd < ) {

        perror("socket error");

        exit();

    }

    bzero(&serAddr, sizeof(serAddr));

    serAddr.sin_family = AF_INET;

    serAddr.sin_port = htons(PORT);

    printf("%s",argv[]);

    //serAddr.sin_addr.s_addr = inet_addr(argv[1]);

    if(inet_pton(AF_INET , argv[] , &serAddr.sin_addr) < )

    {

        printf("inet_pton error for %s\n",argv[]);

        exit();

    }

    if(connect(sockFd, (struct sockaddr*)&serAddr, sizeof(serAddr)) < ) {

        perror("connect error");

        exit();

    };

    char sendLine[MAX_LINE];

    while(fgets(sendLine, MAX_LINE, stdin)!=NULL) {

        write(sockFd, sendLine, strlen(sendLine));

    }

    close(sockFd);

    return ;

}

　　socket服务端：

#include <stdio.h>

#include <stdlib.h>

#include <sys/socket.h>

#include <sys/types.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <string.h>

#define QUEUE 10

#define SIZE 256

int main() {

    //sock fd

    int fd;

    struct sockaddr_in saddr, caddr;

    fd = socket(AF_INET, SOCK_STREAM, );

    if( fd< ){

        perror("socket error");

        exit();

    }

    bzero(&saddr , sizeof(saddr));

    bzero(&caddr , sizeof(caddr));

    saddr.sin_family = AF_INET;

    saddr.sin_port = htons();

    saddr.sin_addr.s_addr = htonl(INADDR_ANY);

    //bind

    int bfd = bind(fd, (struct sockaddr *)&saddr, sizeof(saddr));

    if( bfd< ){

        perror("bind error");

        exit();

    }

    //listen

    int lfd = listen(fd, QUEUE);

    if( lfd< ){

        perror("listen error");

        exit();

    }

    //accept

    socklen_t len = sizeof(caddr);

    int conn = accept(fd, (struct sockaddr *)&caddr, &len);

    if(conn < ){

        perror("conn error");

        exit();

    }

    char buf[SIZE];

    while(read(conn, buf, SIZE) > ) {

        //read

        printf("%s", buf);

        bzero(buf, SIZE);

    }

    close(fd);

    return ;

}

　　socket客户端：

#include <stdio.h>

#include <stdlib.h>

#include <sys/socket.h>

#include <sys/types.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <netdb.h>

#include <string.h>

#define SIZE 256

int main() {

    int fd;

    fd = socket(AF_INET, SOCK_STREAM, );

    struct sockaddr_in saddr;

    bzero(&saddr, sizeof(saddr));

    saddr.sin_family = AF_INET;

    saddr.sin_port = htons();

    saddr.sin_addr.s_addr = inet_addr("127.0.0.1");

    int conn;

    conn = connect(fd, (struct sockaddr*)&saddr, sizeof(saddr));

    if( conn< ) {

        perror("error");

        exit();

    }

    char buf[SIZE];

    while(fgets(buf, SIZE, stdin)!=NULL) {

        printf("%s", buf);

        write(fd, buf, SIZE);

        bzero(buf, SIZE);

    }

    return ;

}

　　参考

　　c++中Socket通信函数之select ： http://blog.csdn.net/piaojun_pj/article/details/5991968/

　　EOF

作者： NONO
出处：http://www.cnblogs.com/diligenceday/

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微信：18101055830

05-11 22:23
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