Winsock编程基继承基础(网络对时程序)

#include <iostream>
#include <stdio.h>

#include "InitSock.h"

using namespace std;

void SetTimeFromTP(ULONG ulTime);

int main(void)
{
    CInitSock initSock;
    //创建套接字
    SOCKET s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (s == INVALID_SOCKET)
    {
        cout << "Failed socke()" << endl;
        return 0;
    }
    //创建套接字之后如果首先sendto可以不绑定
    //若首先recvfrom则需要绑定

    //填写远程地址信息
    sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_port = htons(37);
    addr.sin_addr.S_un.S_addr = inet_addr("129.6.15.28 "); //可在http://tf.nist.gov/service/time-servers.html得到IP

    //连接服务器
    if (connect(s, (sockaddr*)&addr, sizeof(addr)) == -1)
    {
        cout << "Failed connect()" << endl;
        return 0;
    }

    //等待接收时间协议返回的时间,学习Winsock I/O模型后最好使用异步I/O
    ULONG ulTime = 0;
    int nRecv = recv(s, (char*)&ulTime, sizeof(ulTime), 0);
    if (nRecv > 0)
    {
        ulTime = ntohl(ulTime);
        SetTimeFromTP(ulTime);
        cout << "成功与服务器时间同步" << endl;
        cout << "接收到的数据: " << ulTime << endl;
    }
    else
    {
        cout << "服务器不能确认当前时间" << endl;
    }

    closesocket(s);

    getchar();
    return 0;
}

void SetTimeFromTP(ULONG ulTime)
{
    //Windows文件时间是一个64位的值,是从1601年1月1日中午12:00到现在的时间间隔
    //单位是1/1000 0000秒即1000万分之1秒(100-nanosecond)
    FILETIME ft;
    SYSTEMTIME st;
    //首先将基准时间(1900.1.1.0.0.0.0)转换为windows文件时间
    st.wYear = 1900;
    st.wMonth = 1;
    st.wDay = 1;
    st.wHour = 0;
    st.wMinute = 0;
    st.wSecond = 0;
    st.wMilliseconds = 0;

    SystemTimeToFileTime(&st, &ft);
    //然后将Time Protocol使用基准时间加上已经逝去的时间即ulTime
    LONGLONG *pLLong = (LONGLONG*)&ft;
    //注意文件时间的单位
    *pLLong += (LONGLONG)10000000 * ulTime;
    //再将时间转换回来,更新系统时间
    FileTimeToSystemTime(&ft, &st);
    //SetSystemTime(&st);
    cout << st.wYear << "年"
        << st.wMonth << "月"
        << st.wDay << "日"
        << st.wHour + 8<< "时"    //...
        << st.wMinute << "分"
        << st.wSecond << "秒" << endl;

}

原文地址：https://www.cnblogs.com/chenxingyang/p/9748123.html