Winsock.简单UDP

PS：vs2017 编译C++代码 支持 XP：项目属性-->链接器-->系统-->需要的最小版本--> 输入 "5.1"

1、ZC：测试：c向s 发送长度为0的数据，是可行的。（1）用s和c都在本机 测试，OK （2）用 冬的HP笔记本 和 我的联想小新笔记本 测试，OK

2、测试代码：

// SampleUDP_01.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#define _CRT_SECURE_NO_WARNINGS
#define _WINSOCK_DEPRECATED_NO_WARNINGS

#include <iostream>

int main1();
int main2();

int main(int _argc, char** _argv)
{
    std::cout << "Hello World!\n"; 

    if (_argc <= )
    {
        printf("Command line no parameter .");
        return ;
    }

    printf("%s\n", _argv[]);
    if (_argv[][] == 's')
        main1();
    else if (_argv[][] == 'c')
        main2();
    else
        printf("Unknown command line parameter : %s\n", _argv[]);

    return ;
}

#include <stdio.h>
#include <winsock2.h>
#pragma comment(lib, "ws2_32.lib")
#define PORT 8888

int main1()
{
    WSADATA wsaData;
    int Ret = WSAStartup(MAKEWORD(, ), &wsaData);
    printf("Server!\n");
    if (Ret != )
    {
        printf("无法初始化winsock.\n");
        WSACleanup();
}
    else {

        //    printf("初始化winsock成功\n");
    }

    if (LOBYTE(wsaData.wVersion) !=  ||
        HIBYTE(wsaData.wVersion) != )
    {
        WSACleanup();
        return ;
    }

    SOCKET socket = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
    sockaddr_in addr;
    addr.sin_addr.S_un.S_addr = INADDR_ANY;
    addr.sin_family = AF_INET;
    addr.sin_port = ntohs(PORT);

    if (socket == INVALID_SOCKET)
    {
        printf("socket Error!");
    }
    int rs = bind(socket, (sockaddr*)&addr, sizeof(addr));

    if (rs != )
    {
        printf("bind failed!");
        return ;
    }
    char buf[] = "\0";
    char temp[] = "\0";
    sockaddr_in addrcl;
    int len = sizeof(sockaddr);

    while () {

        int iRecv = recvfrom(socket, buf, sizeof(buf), , (sockaddr*)&addrcl, &len);//用新建的地址结构保存客户端的信息 

        if (iRecv == )
        {
            printf("recvfrom len : %d\n", iRecv);
            break;
        }

        sprintf(temp, "%s:%s", inet_ntoa(addrcl.sin_addr), buf);
        sendto(socket, temp, strlen(temp) + , , (sockaddr*)&addrcl, sizeof(addr));
        if (strcmp(buf, "srvexit") == )
        {
            break;
        }
        printf("%s", buf);
    }
    closesocket(socket);

    WSACleanup();
    printf("exit\n");
    return ;
}

#include <WinSock2.h>
#include <stdio.h>
#define PORT 8888
int main2()
{
    WSADATA wsaData;
    int Ret = WSAStartup(MAKEWORD(, ), &wsaData);
    printf("Client..!\n");
    if (Ret != )
    {
        printf("无法初始化winsock.\n");
        WSACleanup();
    }
    else {

        //    printf("初始化winsock成功\n");
    }

    SOCKET socketc = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
    sockaddr_in addr;
    //addr.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
    addr.sin_addr.S_un.S_addr = inet_addr("192.168.2.102");
    addr.sin_family = AF_INET;
    addr.sin_port = ntohs(PORT);

    if (socketc == INVALID_SOCKET)
    {
        printf("socket Error!");
    }

    int len = sizeof(sockaddr);

    while ()//client
    {
        char buf[] = "\0";
        char rbuf[] = "\0";
        printf("\n:");
        scanf("%s", &buf);
        //sendto(socketc, buf, strlen(buf) + 1, 0, (SOCKADDR*)&addr, len);//用回原来的地址结构
        sendto(socketc, buf, , , (SOCKADDR*)&addr, len);//用回原来的地址结构
        break;

        recvfrom(socketc, rbuf, sizeof(rbuf), , (SOCKADDR*)&addr, &len);
        if (strcmp(rbuf, "exit") == )
        {
            break;
        }
        printf("%s", rbuf);

    }

    closesocket(socketc);
    WSACleanup();
    printf("end\n");
    return ;
}

3、vs2017 编译C++代码 支持 XP

　　

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