Winsock 入门 Echo 示例

 #include <stdio.h>
 #include <winsock2.h> 
 
 #pragma comment(lib, "ws2_32") /* WinSock 使用的库函数 */
 
 #define ECHO_DEF_PORT     7 /* 侦听的缺省端口 */
 #define ECHO_BUF_SIZE   256 /* 缓冲区的大小   */
 
 int main(int argc, char **argv)
 {
     WSADATA wsa_data;
     SOCKET  echo_soc = ,      /* 侦听 socket 句柄    */
             acpt_soc = ;
 
     struct sockaddr_in serv_addr,   /* socket的本地地址 */
                        clnt_addr;   /* socket的远端地址 */
     unsigned short port = ECHO_DEF_PORT;
     int result = ;
     int addr_len = sizeof(struct sockaddr_in);
     char recv_buf[ECHO_BUF_SIZE];
 
     if (argc == )
         port = atoi(argv[]);
 
     WSAStartup(MAKEWORD(,), &wsa_data);/* 初始化 WinSock资源 */
     echo_soc = socket(AF_INET, SOCK_STREAM, ); /* 创建 socket */
 
     /* socket 的本地地址 */
     serv_addr.sin_family = AF_INET;
     serv_addr.sin_port = htons(port);
     serv_addr.sin_addr.s_addr = INADDR_ANY;
 
     result = bind(echo_soc, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
     if (result == SOCKET_ERROR)
     {
         printf("[Echo Server] bind error: %d\n", WSAGetLastError());
         closesocket(echo_soc);
         return -;
     }
 
     listen(echo_soc, SOMAXCONN);
 
     printf("[Echo Server] is running ... ...\n");
     while ()
     {
         acpt_soc = accept(echo_soc, (struct sockaddr *)&clnt_addr, &addr_len);
         if (acpt_soc == INVALID_SOCKET)
         {
             printf("[Echo Server] accept error: %d\n", WSAGetLastError());
             break;
         }
 
         result = recv(acpt_soc, recv_buf, ECHO_BUF_SIZE, );
         if (result > )
         {
             recv_buf[result] = ;
             printf("[Echo Server] receives: \"%s\", from %s\r\n",
                    recv_buf, inet_ntoa(clnt_addr.sin_addr));
 
             result = send(acpt_soc, recv_buf, result, );
         }
 
         closesocket(acpt_soc);
     }
 
     closesocket(echo_soc);
     WSACleanup();
 
     return ;
 }

 #include <stdio.h>
 #include <winsock2.h>
 
 #pragma comment(lib, "ws2_32") /* WinSock 使用的库函数    */
 
 #define ECHO_DEF_PORT     7 /* 连接的缺省端口 */
 #define ECHO_BUF_SIZE   256 /* 缓冲区的大小      */
 #define ECHO_DEF_ADD "127.0.0.1"/*连接的默认服务器为本机*/
 
 int main(int argc, char **argv)
 {
     WSADATA wsa_data;
     SOCKET echo_soc = ;      /* socket 句柄 */
     struct sockaddr_in serv_addr;   /* 服务器地址 */
     unsigned short port = ECHO_DEF_PORT;
     char *conAdd=ECHO_DEF_ADD;
     int result = , send_len = ;
     char *test_data = "Hello server!", recv_buf[ECHO_BUF_SIZE];
 
     WSAStartup(MAKEWORD(,), &wsa_data);/* 初始化 WinSock资源 */
     send_len = strlen(test_data);
 
     /* 服务器地址 */
     serv_addr.sin_family = AF_INET;
     serv_addr.sin_port = htons(port);
     serv_addr.sin_addr.s_addr = inet_addr(conAdd);
 
     if (serv_addr.sin_addr.s_addr == INADDR_NONE)
     {
         printf("[ECHO] invalid address\n");
         return -;
     };
 
     echo_soc = socket(AF_INET, SOCK_STREAM, ); /* 创建 socket */
     result = connect(echo_soc, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
 
     if (result == ) /* 连接成功 */
     {
         result = send(echo_soc, test_data, send_len, );
         result = recv(echo_soc, recv_buf, ECHO_BUF_SIZE, );
     }
 
     if (result > )
     {
         recv_buf[result] = ;
         printf("[Echo Client] receives: \"%s\"\r\n", recv_buf);
     }
     else
         printf("[Echo Client] error : %d.\r\n", WSAGetLastError());
 
     getchar();
     closesocket(echo_soc);
     WSACleanup();
 
     return ;
 }