C语言 linux环境基于socket的简易即时通信程序

转载请注明出处：http://www.cnblogs.com/kevince/p/3891033.html      ——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

 /*头文件，client和server编译时都需要使用*/
 #include <unistd.h>
 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <string.h>
 #include <pthread.h>
 #include <stdlib.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>

 #define MSGLEN 1000
 #define IPLEN 15

 typedef int SOCKET;

server.c:

 /*server*/

 #include "head.h"

 char msg_recv[MSGLEN], msg_send[MSGLEN];
 SOCKET server_sockfd, client_sockfd;

 void *thread_function(void *argv) /*线程函数*/
 {
     while(){
         gets(msg_send);
         write(client_sockfd, msg_send, MSGLEN);
     }
     pthread_exit(NULL);
 }

 int main(int arg, char *argv[])
 {
     int server_len, client_len;
     struct sockaddr_in server_address;
     struct sockaddr_in client_address;
     int port;
     int res;

     pthread_t a_thread;
     void *thread_result;

     if (arg != ){
         printf("server --portnum\n");
         exit(EXIT_FAILURE);
     }

     sscanf(argv[], "%d", &port); /*读入端口*/

     server_sockfd = socket(AF_INET, SOCK_STREAM, );
     server_address.sin_family = AF_INET;
     server_address.sin_addr.s_addr = inet_addr("127.0.0.1");
     server_address.sin_port = htons(port);

     server_len = sizeof(server_address);
     bind(server_sockfd, (struct sockaddr *)&server_address, server_len); /*绑定端口并监听*/
     listen(server_sockfd, );
     printf("listen...\n");

     client_len = sizeof(client_address);
     client_sockfd = accept(server_sockfd, (struct sockaddr *)&client_address, &client_len);
     printf("connection success!\n");

     res = pthread_create(&a_thread, NULL, thread_function, NULL); /*启动线程函数*/
     if (res != ){
         perror("Thread creation failed");
         exit(EXIT_FAILURE);
     }

     while(read(client_sockfd, msg_recv, MSGLEN)){
         printf("msg from client: %s\n", msg_recv);
     }
     close(client_sockfd);
     exit(EXIT_SUCCESS);
 }

client.c:

 /*client*/

 #include "head.h"

 char msg_recv[MSGLEN],msg_send[MSGLEN];
 SOCKET sockfd;

 void *thread_function(void *argv) /*线程函数*/
 {
     while(){
         gets(msg_send);
         write(sockfd, msg_send, MSGLEN);
     }
     pthread_exit(NULL);
 }

 int main(int arg, char *argv[])
 {
     struct sockaddr_in address;
     int len;
     int res;
     int port;
     char ip[IPLEN];

     void *thread_result;
     pthread_t a_thread;

     sockfd = socket(AF_INET, SOCK_STREAM, );

     if (arg != ){
         printf("client --ipaddress --portnum\n");
         exit(EXIT_FAILURE);
     }

     sscanf(argv[], "%s", ip);
     sscanf(argv[], "%d", &port); /*读取ip与端口*/

     address.sin_family = AF_INET;
     address.sin_addr.s_addr = inet_addr(ip);
     address.sin_port = htons(port);

     len = sizeof(address);
     res = connect(sockfd, (struct sockaddr *)&address, len);
     if (res == -){
         perror("connect failed! ");
         exit(EXIT_FAILURE);
     }
     printf("connection success!\n");

     res = pthread_create(&a_thread, NULL, thread_function, NULL); /*启动线程函数*/
     if (res != ){
         perror("Thread creation failed");
         exit(EXIT_FAILURE);
     }

     while(read(sockfd, msg_recv, MSGLEN)){
         printf("msg from server: %s\n", msg_recv);
     }
     res = pthread_join(a_thread, &thread_result);
     if (res != ){
         perror("joined failed");
         exit(EXIT_FAILURE);
     }
     exit(EXIT_SUCCESS);
 }

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 -lpthread

gcc -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。