windows获取网络时间，同步系统时间方法

/*可用的时间服务器 "time-a.timefreq.bldrdoc.gov" "time-b.timefreq.bldrdoc.gov" "time-c.timefreq.bldrdoc.gov" "utcnist.colorado.edu" "time-nw.nist.gov" "nist1.nyc.certifiedtime.com" "nist1.dc.certifiedtime.com" "nist1.sjc.certifiedtime.com" "nist1.datum.com" "ntp2.cmc.ec.gc.ca" "ntps1-0.uni-erlangen.de" "ntps1-1.uni-erlangen.de" "ntps1-2.uni-erlangen.de" "ntps1-0.cs.tu-berlin.de" "time.ien.it" "ptbtime1.ptb.de" "ptbtime2.ptb.de" */ // strServer：时间服务器网址； 37：端口号 BOOL GetInternetTime(CTime* pTime, CString strServer =_T("utcnist.colorado.edu"), int nPort=37); //同步系统时钟 BOOL SyncSystemClock(CTime tmServer); BOOL CSyncTime::GetInternetTime(CTime* pTime, CString strServer, int nPort) { CSocket sockClient; sockClient.Create(); //创建socket ///获取当前系统时间 time_t tstart; time(&tstart); BOOL bRet = sockClient.Connect((LPCTSTR)strServer, nPort); // strServer：时间服务器网址； 37：端口号 if (!bRet) { return bRet; } DWORD dwTime = 0; //用来存放服务器传来的标准时间数据 unsigned char nTime[8]; //临时接收数据 memset(nTime, 0, sizeof(nTime)); sockClient.Receive(nTime, sizeof(nTime)); //接收服务器发送来得4个字节的数据 sockClient.Close(); //关闭socket dwTime += nTime[0] << 24; //整合数据 dwTime += nTime[1] << 16; dwTime += nTime[2] << 8; dwTime += nTime[3]; if(0 == dwTime) { return FALSE; } //服务器传来的数据是自从1900年以来的秒数 //取得 1900~1970 的时间差(以秒数计算) ，放在dwSpan里面 COleDateTime t00( 1900, 1, 1, 0, 0, 0 ); // 1900.1.1 00:00:00 COleDateTime t70( 1970, 1, 1, 0, 0, 0 ); // 1970.1.1 00:00:00 COleDateTimeSpan ts70to00 = t70 - t00; DWORD dwSpan = (DWORD)ts70to00.GetTotalSeconds(); ASSERT( dwSpan == 2208988800L ); ///获取当前系统时间 time_t tstop; time(&tstop); ///计算延迟时间 m_dwDely = tstop - tstart; //把时间变为基于1970年的，便于用CTime处理 dwTime -= dwSpan; //考虑网络延迟因素 dwTime += m_dwDely; //构造当前时间的CTime对象 CTime timeNow = (CTime)dwTime; *pTime = timeNow; return TRUE; } BOOL SyncSystemClock(CTime tmServer) { //如果是在XP下，则先提升进程的权限 OSVERSIONINFO osv; osv.dwOSVersionInfoSize=sizeof OSVERSIONINFO; GetVersionEx(&osv); if(osv.dwPlatformId==VER_PLATFORM_WIN32_NT) { HANDLE hToken; TOKEN_PRIVILEGES tkp; // Get a token for this process. if (!OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hToken)) return( FALSE ); // Get the LUID for the shutdown privilege. LookupPrivilegeValue(NULL, SE_SYSTEMTIME_NAME, &tkp.Privileges[0].Luid); tkp.PrivilegeCount = 1; // one privilege to set tkp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED; // Get the shutdown privilege for this process. AdjustTokenPrivileges(hToken, FALSE, &tkp, 0, (PTOKEN_PRIVILEGES)NULL, 0); if (GetLastError() != ERROR_SUCCESS) return FALSE; } //设置系统时间 SYSTEMTIME systm; systm.wYear = tmServer.GetYear(); systm.wMonth = tmServer.GetMonth(); systm.wDay = tmServer.GetDay(); systm.wHour = tmServer.GetHour(); systm.wMinute = tmServer.GetMinute(); systm.wSecond = tmServer.GetSecond(); systm.wMilliseconds = 0; if(0 != ::SetLocalTime(&systm)) { return TRUE; } else { return FALSE; } }

上面的代码在VC6上使用没有问题，在vs2005上使用时发现了GetTotalSeconds()有溢出现象

所以代码修改如下:

 

BOOL CSyncTimeDlg::GetInternetTime(CTime* pTime, CString strServer) { CSocket sockClient; sockClient.Create(); //创建socket time_t tstart; time(&tstart); //for debug m_info += "Connect server: " + strServer + ".../r/n"; UpdateData(FALSE); //for debug BOOL bRet = sockClient.Connect((LPCTSTR)strServer, 37); // strServer：时间服务器网址； 37：端口号 DWORD dwTime = 0; //用来存放服务器传来的标准时间数据 unsigned char nTime[8]; //临时接收数据 memset(nTime, 0, sizeof(nTime)); sockClient.Receive(nTime, sizeof(nTime)); //接收服务器发送来得4个字节的数据 sockClient.Close(); //关闭socket //for debug m_info += "Connect shut down./r/n"; UpdateData(FALSE); //for debug dwTime += nTime[0] << 24; //整合数据 dwTime += nTime[1] << 16; dwTime += nTime[2] << 8; dwTime += nTime[3]; if(0 == dwTime) return FALSE; //for debug CString strSec(""); strSec.Format("Receive value : %u/r/n", dwTime); m_info += strSec; UpdateData(FALSE); //for debug //服务器传来的数据是自从1900年以来的秒数 //取得 1900~1970 的时间差(以秒数计算) ，放在dwSpan里面 COleDateTime t00( 1900, 1, 1, 0, 0, 0 ); // 1900.1.1 00:00:00 COleDateTime t70( 1970, 1, 1, 0, 0, 0 ); // 1970.1.1 00:00:00 COleDateTimeSpan ts70to00 = t70 - t00; DWORD dwSpan = ts70to00.m_span*24*60*60; ASSERT( dwSpan == 2208988800L ); ///获取当前系统时间 time_t tstop; time(&tstop); ///计算延迟时间 dwDely = tstop - tstart; //把时间变为基于1970年的，便于用CTime处理 dwTime -= dwSpan; //考虑网络延迟因素 dwTime += dwDely; //构造当前时间的CTime对象 CTime timeNow = (CTime)dwTime; //for debug m_info += timeNow.Format("%Y.%m.%d %H:%M:%S /r/n"); UpdateData(FALSE); //for debug *pTime = timeNow; return TRUE; }