MFC 运行日志

void WriteLog(CString Msg)
{
CTime tm =CTime::GetCurrentTime();
CString str = tm.Format("%Y-%m-%d-%H-%M-%S");
CString sPage = str + "     "+Msg+"r"+"n";
CFile logfile (_T("C:\RunLog.log"), CFile::modeNoTruncate|CFile::modeReadWrite|CFile::modeCreate);
logfile.SeekToEnd();
logfile.Write(sPage,sPage.GetLength());
logfile.Flush();
logfile.Close();
}