可以在同一台电脑上运行，在一个终端上运行服务器端，在一个终端上运行客户端。
服务器端的IP地址要和本地的IP相同，并分配端口号，，客户端的默认设置为本地，端口号自动分配。
服务器端：
#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>#define MAXBUF 1024int main(int argc, char *argv[]){int pid;int sockfd, new_fd;socklen_t len;struct sockaddr_in my_addr, their_addr;unsigned int myport, lisnum;char buf[MAXBUF + 1];if (argv[2])myport = atoi(argv[2]);elsemyport = 7575;if (argv[3])lisnum = atoi(argv[3]);elselisnum = 5;if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){perror("socket");exit(EXIT_FAILURE);}bzero(&my_addr, sizeof(my_addr));my_addr.sin_family = AF_INET;my_addr.sin_port = htons(myport);if (argv[1])my_addr.sin_addr.s_addr = inet_addr(argv[1]);elsemy_addr.sin_addr.s_addr = INADDR_ANY;if (bind(sockfd, (struct sockaddr *) &my_addr, sizeof(struct sockaddr))== -1){perror("bind");exit(EXIT_FAILURE);}if (listen(sockfd,lisnum ) == -1){perror("listen");exit(EXIT_FAILURE);}printf("wait for connect\n");len = sizeof(struct sockaddr);if ((new_fd =accept(sockfd, (struct sockaddr *) &their_addr,&len)) == -1){perror("accept");exit(EXIT_FAILURE);}elseprintf("server: got connection from %s, port %d, socket %d\n",inet_ntoa(their_addr.sin_addr),ntohs(their_addr.sin_port), new_fd);if(-1==(pid=fork())){perror("fork");exit(EXIT_FAILURE);}else if( pid == 0){while (1) {bzero(buf, MAXBUF + 1);printf("input the message to send:");fgets(buf, MAXBUF, stdin);if (!strncasecmp(buf, "quit", 4)){printf("i will close the connect!\n");break;}len = send(new_fd, buf, strlen(buf) – 1, 0);if (len < 0){printf("message'%s' send failure!errno code is %d,errno message is '%s'\n",buf, errno, strerror(errno));break;}}}else {while(1){bzero(buf, MAXBUF + 1);len = recv(new_fd, buf, MAXBUF, 0);if (len > 0)printf("message recv successful :'%s',%dByte recv\n",buf, len);else if (len < 0){printf("recv failure!errno code is %d,errno message is '%s'\n",errno, strerror(errno));break;}else{printf("the other one close quit\n");break;}}}close(new_fd);close(sockfd);return 0;}
客户端：
#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>#define MAXBUF 1024int main(int argc, char **argv){int sockfd, len;struct sockaddr_in dest;char buffer[MAXBUF + 1];if (argc != 3){printf(" error format,it must be:\n\t\t%s IP port\n",argv[0]);exit(EXIT_FAILURE);}if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {perror("Socket");exit(errno);}printf("socket created\n");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);}if (connect(sockfd, (struct sockaddr *) &dest, sizeof(dest))==-1){perror("Connect ");exit(errno);}printf("server connected\n");pid_t pid;if(-1==(pid=fork())){perror("fork");exit(EXIT_FAILURE);}else if (pid==0){while (1) {bzero(buffer, MAXBUF + 1);len = recv(sockfd, buffer, MAXBUF, 0);if (len > 0)printf("recv successful:'%s',%d byte recv\n",buffer, len);else if(len < 0){perror("recv");break;}else{printf("the other one close ,quit\n");break;}}}else{while (1) {bzero(buffer, MAXBUF + 1);printf("pls send message to send:");fgets(buffer, MAXBUF, stdin);if (!strncasecmp(buffer, "quit", 4)){printf(" i will quit!\n");break;}len = send(sockfd, buffer, strlen(buffer) – 1, 0);if (len < 0){perror("send");break;}}}close(sockfd);return 0;}
服务器端执行 ： ./s 192.168.142.132 7575 5
客户端执行： ./c 192.168.142.132 7575
其中，192.168.142.132是本机的IP地址.
服务器端信息：
root@jieniyimiao-virtual-machine:/home/jieniyimiao/c_code/linux/ch13/sock_tcp_p_p_chat# ./s 192.168.142.132 7575 5wait for connectserver: got connection from 192.168.142.132, port 44698, socket 4input the message to send:jieniyimiapinput the message to send:dddddddddddddddddddddddddddinput the message to send:ddddddddddddddddddddddddddddinput the message to send:aaaaaaaaaaaaaaaaaaaaaainput the message to send:aaaaaaaaaaaaaaaaaaaaaaaainput the message to send:message recv successful :’dddddddddddddddddd’,18Byte recvmessage recv successful :’ddddddddddddddddd’,17Byte recvmessage recv successful :’ddddddddddddddddd’,17Byte recvmessage recv successful :’dddddddddddddd’,14Byte recvmessage recv successful :’ddddddddddddddd’,15Byte recvmessage recv successful :’ddddddddddddddddd’,17Byte recvmessage recv successful :’dddddddddddddd’,14Byte recvquiti will close the connect!
客户端略：
用NETSTAT查看信息如下：
# netstat |grep 192.168.142.132
来说是非者，便是是非人。
