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 = 0,      /* 侦听 socket 句柄    */
            acpt_soc = 0;

    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 = 0;
    int addr_len = sizeof(struct sockaddr_in);
    char recv_buf[ECHO_BUF_SIZE];

    if (argc == 2)
        port = atoi(argv[1]);

    WSAStartup(MAKEWORD(2,0), &wsa_data);/* 初始化 WinSock资源 */
    echo_soc = socket(AF_INET, SOCK_STREAM, 0); /* 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
", WSAGetLastError());
        closesocket(echo_soc);
        return -1;
    }
    
    listen(echo_soc, SOMAXCONN);

    printf("[Echo Server] is running ... ...
");
    while (1)
    {
        acpt_soc = accept(echo_soc, (struct sockaddr *)&clnt_addr, &addr_len);
        if (acpt_soc == INVALID_SOCKET)
        {
            printf("[Echo Server] accept error: %d
", WSAGetLastError());
            break;
        }

        result = recv(acpt_soc, recv_buf, ECHO_BUF_SIZE, 0);
        if (result > 0)
        {
            recv_buf[result] = 0;
            printf("[Echo Server] receives: "%s", from %s
", 
                   recv_buf, inet_ntoa(clnt_addr.sin_addr));

            result = send(acpt_soc, recv_buf, result, 0);
        }

        closesocket(acpt_soc);
    }

    closesocket(echo_soc);
    WSACleanup();

    return 0;
}

#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 = 0;      /* 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 = 0, send_len = 0;
    char *test_data = "Hello server!", recv_buf[ECHO_BUF_SIZE];

    WSAStartup(MAKEWORD(2,0), &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
");
        return -1;
    };

    echo_soc = socket(AF_INET, SOCK_STREAM, 0); /* 创建 socket */
    result = connect(echo_soc, (struct sockaddr *)&serv_addr, sizeof(serv_addr));

    if (result == 0) /* 连接成功 */
    {
        result = send(echo_soc, test_data, send_len, 0);
        result = recv(echo_soc, recv_buf, ECHO_BUF_SIZE, 0);
    }

    if (result > 0)
    {
        recv_buf[result] = 0;
        printf("[Echo Client] receives: "%s"
", recv_buf);
    }
    else
        printf("[Echo Client] error : %d.
", WSAGetLastError());

    getchar();
    closesocket(echo_soc);
    WSACleanup();

    return 0;
}