WTS LastInputTime - c++

Question

i'm trying to retrive the difference between CurrentTime and LastInputTime and comparing it to another value. CurrentTime is updating correctly but LastInputTime is always a constant value, i dont know why sometimes is 0 , sometimes is other constant value . Any help ?
void localSessions()
{
while (TRUE)
{
cout << "Risky local logon sessions :" << endl;
DWORD pCount;
PWTS_SESSION_INFO pSessionsInfo=new WTS_SESSION_INFO[MAX_SESSIONS];
WTSEnumerateSessionsA(WTS_CURRENT_SERVER_HANDLE, 0, 1, &pSessionsInfo, &pCount);
DWORD bytes;
for (auto it = 0; it < pCount; it++)
{
WTSINFOEX* ptr;
if (pSessionsInfo[it].State == WTSActive)
{
INT ret = WTSQuerySessionInformationA(WTS_CURRENT_SERVER_HANDLE, pSessionsInfo[it].SessionId, WTSSessionInfoEx, (LPSTR*)&ptr, &bytes);
if (ret != 0)
{
INT ret = Gambit::OS::Environment::GetOSVersion();
INT unlocked = 0, unknown = 0;
LONGLONG last_input = ptr->Data.WTSInfoExLevel1.CurrentTime.QuadPart - ptr->Data.WTSInfoExLevel1.LastInputTime.QuadPart;
cout << last_input << endl;
HANDLE token;
WTSQueryUserToken(pSessionsInfo[it].SessionId, &token);
ImpersonateLoggedOnUser(token);
BOOL active;
SystemParametersInfo(SPI_GETSCREENSAVERRUNNING, 0, &active, 0);
RevertToSelf();
if (!(ret >= 16 && ret <= 19))
{
if ((ptr->Data.WTSInfoExLevel1.SessionFlags & WTS_SESSIONSTATE_UNLOCK) != 0)
{
unlocked = 1;
}
}
else if (ret >= 16 && ret <= 19)
{
if ((ptr->Data.WTSInfoExLevel1.SessionFlags & WTS_SESSIONSTATE_LOCK) != 0)
{
unlocked = 1;
}
}
if (unlocked == 1 && active == FALSE && last_input > 500000000000)
{
cout << "Winstation name : " << ptr->Data.WTSInfoExLevel1.WinStationName << endl;
cout << "UserName name : " << ptr->Data.WTSInfoExLevel1.UserName << endl;
cout << "Domain name : " << ptr->Data.WTSInfoExLevel1.DomainName << endl;
}
cout << endl;
}
}
}
cout << endl << endl;
Sleep(1000);
}
}

Answer 1

LastInputTime is zero for a local session.
For a remote session, when there is no user input after last query of LastInputTime, it will keep unchanged. If there is a user input (like mouse move etc), LastInputTime will update to new time.
If you want to monitor local session user input time you can use GetLastInputInfo instead.