Windows not automatically detecting registry changes

[Phobic]

I have an app that disables some of the log on features, like HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\DisableTaskMgr, and the registry will see the changes, but Windows won't acknowledge the changes until my app closes. However, if I make the changes directly into the registry editor, Windows will acknowledge the changes. What's the deal? Is this atleast supposed to happen, because if so I don't think it will hurt the functionality of my app; I just don't want to have to worry about differences between different systems.

I'm using Windows XP by the way, and this app is designed for XP.

[sunburnt]

make sure you're closing the registry key!

[Phobic]

Hah, thanks for that thought, but I've already looked into that. Same problem.

[crptcblade]

Why not post some code up and we'll have a look see.

[Phobic]

Registry Code:

BOOL SaveDWORD (HKEY lpszKey, LPCTSTR lpszSubkey, LPCTSTR lpszValueName, DWORD dwValue)
{
    //Registry Key Handle
    HKEY    CurKey;

    BOOL    fRes=FALSE;

    if (lpszSubkey != NULL && lpszValueName != NULL)
    {
        if (strlen(lpszSubkey) > 0 && strlen(lpszValueName) > 0)
        {
            if (RegOpenKey(lpszKey, lpszSubkey, &CurKey) == ERROR_SUCCESS)
            {
                if (RegSetValueEx(CurKey, lpszValueName, 0, REG_DWORD, (PBYTE)&dwValue, sizeof(DWORD)) == ERROR_SUCCESS)
                    fRes = TRUE;
            }
            else
            {
                // Create new key
                if (RegCreateKey(lpszKey, lpszSubkey, &CurKey) == ERROR_SUCCESS)
                {
                    if (RegSetValueEx(CurKey, lpszValueName, 0, REG_DWORD, (PBYTE)&dwValue, sizeof(DWORD)) == ERROR_SUCCESS)
                        fRes = TRUE;
                }
            }
        }
    }
    RegCloseKey (CurKey);
    return fRes;
} 

Program close code:

PostQuitMessage(0); 

Registry settings being modified:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\DisableChangePassword
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\DisableLockWorkstation
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\DisableTaskMgr
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\NoLogoff

To reiterate: I know the save code works because the registry values do change; the issue is that Windows (XP) doesn't aknowledge the changes with the login screen until my app closes.

As bad as it may look, I'm not trying to write a virus or anything Another question that goes with this, how do I determine the logged on user's permissions (login name, administrative account or limited acount, registry permissions)? Thanks.

[wey97]

RegOpenKey, RegCreateKey, and RegSetValue are 16-bit
Windows and should not be used anymore.

RegOpenKeyEx, RegCreateKeyEx, and RegSetValueEx should be used.

BOOL SaveDWORD(HKEY hKey, LPCTSTR lpSubKey, LPCTSTR lpValueName, DWORD dwValue)
{

	HKEY	hCurKey;
	BOOL	bRet = FALSE;

	if (lpSubKey != NULL && lpValueName != NULL)
	{
		if (strlen(lpSubKey) > 0 && strlen(lpValueName) > 0)
		{
			if (RegOpenKeyEx(hKey, lpSubKey, 0, KEY_SET_VALUE, &hCurKey) == ERROR_SUCCESS)
			{
				if (RegSetValueEx(hCurKey, lpValueName, 0, REG_DWORD, 
					(LPBYTE)&dwValue, sizeof(DWORD)) == ERROR_SUCCESS)
				{
					bRet = TRUE;
				}
			}
			else
			{
				if (RegCreateKeyEx(hKey, lpSubKey, 0, NULL, REG_OPTION_NON_VOLATILE,
					KEY_SET_VALUE, NULL, &hCurKey, NULL) == ERROR_SUCCESS)
				{
					if (RegSetValueEx(hCurKey, lpValueName, 0, REG_DWORD, 
						(LPBYTE)&dwValue, sizeof(DWORD)) == ERROR_SUCCESS)
					{
						bRet = TRUE;
					}
				}
			}
		}
	}
	
	RegCloseKey(hCurKey);
	
	return bRet;
}