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最近在看linux網絡編程相關，現學現賣，就寫了一個簡易的C/S即時通信程序，代碼如下：

head.h

 1 /*頭文件，client和server編譯時都需要使用*/ 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 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) /*線程函數*/ 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); /*讀入端口*/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); /*綁定端口并監聽*/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); /*啟動線程函數*/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) /*線程函數*/ 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); /*讀取ip與端口*/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); /*啟動線程函數*/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 }

由于使用了線程，所以要鏈接正確的線程庫，所以編譯命令如下：

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

如果你的系統默認使用的就是NPTL線程庫，那么編譯時就無需加上-I和-L選項

運行時輸入的命令規則是：

./server --portnum  #即server后面要加上需要綁定的端口號。./client --ip --portnum  #即client后面要加上服務器的IP地址以及端口號。

不積跬步無以至千里，雖然這兩個程序很簡單，但作為我的第一個linux環境下基于socket的通信程序，也很有紀念意義。