WIN网络编程-NetTime

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// NetTime.cpp文件

//通过internet从129.132.2.21中获取时间信息

#include "../common/InitSock.h"
#include <stdio.h>
CInitSock initSock;<wbr></wbr>

void SetTimeFromTP(ULONG ulTime)<wbr>//根据时间协议返回的时间设置系统时间<br>{<br><wbr>//Windows文件时间是一个64位的值，它是从1601年1月1日中午12:00到现在的时间间隔，<br><wbr>// 单位是1/1000 0000秒，即1000万分之1秒（100-nanosecond）<br><wbr>FILETIME ft;<br><wbr>SYSTEMTIME st;</wbr></wbr></wbr></wbr></wbr>

<wbr>//首先将基准时间（1900年1月1日0点0分0秒0毫秒）转化为Windows文件时间<wbr><br><wbr>st.wYear = 1900;<br><wbr>st.wMonth = 1;<br><wbr>st.wDay = 1;<br><wbr>st.wHour = 0;<br><wbr>st.wMinute = 0;<br><wbr>st.wSecond = 0;<br><wbr>st.wMilliseconds = 0;<br><wbr>SystemTimeToFileTime(&amp;st,&amp;ft);</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr>// 然后将TimeProtocol使用的基准时间加上以及逝去的时间，即ulTime<br><wbr>LONGLONG *pLLong = (LONGLONG*)&amp;ft;<br><wbr>// 注意，文件时间单位是1/10000000秒，即1000万分之1秒（100-nanosecond ）<br><wbr>*pLLong += (LONGLONG)10000000 * ulTime;</wbr></wbr></wbr></wbr>

<wbr>// 再将时间转化回来，更新系统时间<br><wbr>FileTimeToSystemTime(&amp;ft,&amp;st);<wbr><br><wbr>SetSystemTime(&amp;st);<br>}</wbr></wbr></wbr></wbr>

int main()
{
<wbr>SOCKET s = ::socket(AF_INET, SOCK_STREAM,IPPROTO_TCP);<br><wbr>if(s == INVALID_SOCKET)<br><wbr>{<br><wbr><wbr>printf(" Failed socket()\n");<br><wbr><wbr>return 0;<br><wbr>}</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr>// 填写远程地址信息，连接到时间服务器<br><wbr>sockaddr_in servAddr;<br><wbr>servAddr.sin_family = AF_INET;<br><wbr>servAddr.sin_port = htons(37);<br><wbr>//这里使用的时间服务器是129.132.2.21，更多地址请参考http://tf.nist.gov/service/its.htm<br><wbr>servAddr.sin_addr.S_un.S_addr =inet_addr("129.132.2.21");<br><wbr>if(::connect(s,(sockaddr*)&amp;servAddr, sizeof(servAddr)) ==-1)<br><wbr>{<br><wbr><wbr>printf(" Failed connect()\n");<br><wbr><wbr>return 0;<br><wbr>}<br><wbr><br><wbr>// 等待接收时间协议返回的时间。学习了WinsockI/O模型之后，最好使用异步I/O，以便设置超时<br><wbr>ULONG ulTime = 0;<br><wbr>int nRecv = ::recv(s,(char*)&amp;ulTime, sizeof(ulTime), 0);<br><wbr>if(nRecv &gt; 0)<br><wbr>{<br><wbr><wbr>ulTime = ntohl(ulTime);<br><wbr><wbr>SetTimeFromTP(ulTime);<br><wbr><wbr>printf("成功与时间服务器的时间同步！\n");<br><wbr>}<br><wbr>else<br><wbr>{<br><wbr><wbr>printf("时间服务器不能确定当前时间！\n");<br><wbr>}<br><wbr><br><wbr>::closesocket(s);<br><wbr>return 0;<br>}</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>