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[000]socket通信--server和client实现的简单例子

在C语言中就学过scanf和printf,其实理解socket就跟这两个输入输出差不多,只不过是信息的传输而已。

1.TCP服务器端(server)的默认函数调用顺序:

按照上述的调用顺序,我们可以来写个最简单的"hello world" server程序。

 1 #include<stdio.h> 2 #include<stdlib.h> 3 #include<string.h> 4 #include<unistd.h> 5 #include<arpa/inet.h> 6 #include<sys/socket.h> 7  8 void error_handling(char* message); 9 10 void error_handling(char* message) {11     fputs(message, stderr);12     fputc(\n, stderr);13     exit(1);14 }15 16 int main(int argc, char **argv)17 {18     int serv_sock;19      int clnt_sock;20    21     //设置一个server地址serv_addr,client地址clnt_addr22     struct sockaddr_in serv_addr;23     struct sockaddr_in clnt_addr;24     socklen_t clnt_addr_size = sizeof(clnt_addr);25 26     memset(&serv_addr, 0, sizeof(serv_addr));27     memset(&serv_addr, 0, sizeof(serv_addr));28     char message[] = "Hello world";29 30     if (argc != 2) {31         printf("Usage : %s <port>\n", argv[0]);32         exit(1);33     }34 35     //创建用于internet的流协议(TCP)socket36     serv_sock = socket(PF_INET, SOCK_STREAM, 0);37     if (serv_sock == -1) {38         error_handling("socket() error");39     }40  41     serv_addr.sin_family = AF_INET;42     serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);43     serv_addr.sin_port = htons(atoi(argv[1]));44 45     //把socket和socket地址结构联系起来46     if( bind(serv_sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr)) == -1) {47         error_handling("bind() error");48     }49 50     //server_socket用于监听51     if ( listen(serv_sock, 5) == -1) {52         error_handling("lisen() error");53     }54 55     // 受理连接请求56     clnt_sock = accept(serv_sock,(struct sockaddr*)&clnt_addr,&clnt_addr_size);57     if ( clnt_sock == -1) {58         error_handling("accept() error");59     }60 61     write(clnt_sock, message, sizeof(message));62     close(clnt_sock);63     close(serv_sock);64 65     return 0;66 }

2.与server端相对应的是客户端,其调用顺序为:

相对应的“hello world”client端程序就为:

 1 hello_client.c 2 ------ 3 #include<stdio.h> 4 #include<stdlib.h> 5 #include<string.h> 6 #include<unistd.h> 7 #include<arpa/inet.h> 8 #include<sys/socket.h> 9 10 void error_handling(char* message);11 12 void error_handling(char* message) {13     fputs(message, stderr);14     fputc(\n, stderr);15     exit(1);16 }17 18 int main(int argc, char **argv) {19     int sock;20     struct sockaddr_in serv_addr;21     char message[30];22     int str_len;23     memset(&serv_addr, 0, sizeof(serv_addr));24 25     if (argc != 3)26     {27         printf("Usage: /%s <IP> <Port>\n",argv[0]);28         exit(1);29     }30 31     //创建用于internet的流协议(TCP)socket32     sock = socket(PF_INET, SOCK_STREAM, 0);33     if (sock == -1) {34         error_handling("socket() error");35     }36 37     //设置一个socket地址结构client_addr,代表客户机internet地址, 端口38     serv_addr.sin_family = AF_INET;39     serv_addr.sin_addr.s_addr = inet_addr(argv[1]);40     serv_addr.sin_port = htons(atoi(argv[2]));41 42     //把socket和socket地址结构联系起来43     if( connect(sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr)) == -1) {44         error_handling("connect() error");45     }46 47     str_len = read(sock, message, sizeof(message) - 1);48     if (str_len == -1) {49         error_handling("read() error");50     }51 52     printf("Message from server : %s \n", message);53     close(sock);54     return 0;55 }

开始运行服务器端:

#gcc hello_server.c -o hserver #./hserver 9010......开始挂起

开始运行客户端:

#gcc hello_client.c -o hclient #./hclient 127.0.0.1 9010Message from server: Hello world

 

[000]socket通信--server和client实现的简单例子