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

 1 /*头文件，client和server编译时都需要使用*/
 2 #include <unistd.h>
 3 #include <stdio.h>
 4 #include <sys/types.h>
 5 #include <sys/socket.h>
 6 #include <string.h>
 7 #include <pthread.h>
 8 #include <stdlib.h>
 9 #include <netinet/in.h>
10 #include <arpa/inet.h>
11 
12 #define MSGLEN 1000
13 #define IPLEN 15
14 
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 -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。