转载请注明出处： ——By Kevince
最近在看linux网络编程相关，现学现卖，就写了一个简易的C/S即时通信程序，代码如下：
head.h
1 /*头文件，client和server编译时都需要使用*/ 2 #include3 #include 4 #include 5 #include 6 #include 7 #include 8 #include 9 #include 10 #include 11 12 #define MSGLEN 100013 #define IPLEN 1514 15 typedef int SOCKET;
server.c:
1 /*server*/ 2 3 #include "head.h" 4 5 char msg_recv[MSGLEN], msg_send[MSGLEN]; 6 SOCKET server_sockfd, client_sockfd; 7 8 void *thread_function(void *argv) /*线程函数*/ 9 {10 while(1){11 gets(msg_send);12 write(client_sockfd, msg_send, MSGLEN);13 }14 pthread_exit(NULL);15 }16 17 int main(int arg, char *argv[])18 {19 int server_len, client_len;20 struct sockaddr_in server_address;21 struct sockaddr_in client_address;22 int port;23 int res;24 25 pthread_t a_thread;26 void *thread_result;27 28 if (arg != 2){29 printf("server --portnum\n");30 exit(EXIT_FAILURE);31 }32 33 sscanf(argv[1], "%d", &port); /*读入端口*/34 35 server_sockfd = socket(AF_INET, SOCK_STREAM, 0);36 server_address.sin_family = AF_INET;37 server_address.sin_addr.s_addr = inet_addr("127.0.0.1");38 server_address.sin_port = htons(port);39 40 server_len = sizeof(server_address);41 bind(server_sockfd, (struct sockaddr *)&server_address, server_len); /*绑定端口并监听*/42 listen(server_sockfd, 10);43 printf("listen...\n");44 45 client_len = sizeof(client_address);46 client_sockfd = accept(server_sockfd, (struct sockaddr *)&client_address, &client_len);47 printf("connection success!\n");48 49 res = pthread_create(&a_thread, NULL, thread_function, NULL); /*启动线程函数*/50 if (res != 0){51 perror("Thread creation failed");52 exit(EXIT_FAILURE);53 }54 55 while(read(client_sockfd, msg_recv, MSGLEN)){56 printf("msg from client: %s\n", msg_recv);57 }58 close(client_sockfd);59 exit(EXIT_SUCCESS);60 }
client.c:
1 /*client*/ 2 3 #include "head.h" 4 5 char msg_recv[MSGLEN],msg_send[MSGLEN]; 6 SOCKET sockfd; 7 8 void *thread_function(void *argv) /*线程函数*/ 9 {10 while(1){11 gets(msg_send);12 write(sockfd, msg_send, MSGLEN);13 }14 pthread_exit(NULL);15 }16 17 int main(int arg, char *argv[])18 {19 struct sockaddr_in address;20 int len;21 int res;22 int port;23 char ip[IPLEN];24 25 void *thread_result;26 pthread_t a_thread;27 28 sockfd = socket(AF_INET, SOCK_STREAM, 0);29 30 if (arg != 3){31 printf("client --ipaddress --portnum\n");32 exit(EXIT_FAILURE);33 }34 35 sscanf(argv[1], "%s", ip);36 sscanf(argv[2], "%d", &port); /*读取ip与端口*/37 38 address.sin_family = AF_INET;39 address.sin_addr.s_addr = inet_addr(ip);40 address.sin_port = htons(port);41 42 len = sizeof(address);43 res = connect(sockfd, (struct sockaddr *)&address, len);44 if (res == -1){45 perror("connect failed! ");46 exit(EXIT_FAILURE);47 }48 printf("connection success!\n");49 50 res = pthread_create(&a_thread, NULL, thread_function, NULL); /*启动线程函数*/51 if (res != 0){52 perror("Thread creation failed");53 exit(EXIT_FAILURE);54 }55 56 while(read(sockfd, msg_recv, MSGLEN)){57 printf("msg from server: %s\n", msg_recv);58 }59 res = pthread_join(a_thread, &thread_result);60 if (res != 0){61 perror("joined failed");62 exit(EXIT_FAILURE);63 }64 exit(EXIT_SUCCESS);65 }
由于使用了线程，所以要链接正确的线程库，所以编译命令如下：
gcc -D_REENTRANT -I/usr/include/nptl server.c -o server -L/usr/lib/nptl -lpthreadgcc -D_REENTRANT -I/usr/include/nptl client.c -o client -L/usr/lib/nptl -lpthread
如果你的系统默认使用的就是NPTL线程库，那么编译时就无需加上-I和-L选项
运行时输入的命令规则是：
./server --portnum #即server后面要加上需要绑定的端口号。./client --ip --portnum #即client后面要加上服务器的IP地址以及端口号。
不积跬步无以至千里，虽然这两个程序很简单，但作为我的第一个linux环境下基于socket的通信程序，也很有纪念意义。