Different return values for RegDBKeyExist on 64-bit machines

[mrohit]

Hi,

I am having issues with RegDBKeyExist function on a 64-bit OS.
I have the following scenario:
Installed a 32-bit application ABC on 64-bit machine. So the registry looks like
HKLM\SOFTWARE\Wow6432Node\ABC.

I want to check existence of ABC on 64-bit machine and i execute RegDBKeyExist (HKLM\SOFTWARE\Wow6432Node\ABC).

Prior to this i am also setting
REGDB_OPTIONS = REGDB_OPTIONS | REGDB_OPTION_WOW64_64KEY;
RegDBSetDefaultRoot ( HKEY_LOCAL_MACHINE );

On,
1. Windows Server SP2 machine it returns value < 0,
2. Windows Server 2008 R2 machine it returns 1.

Has anybody encountered similar kind of issue?
Is this due to the windows operating system or due to IS2010?

Any update/information would be helpful.

Thank You
Rohit

[joshstechnij]

This is an issue with the registry support on the operating system. RegDBKeyExist calls the RegOpenKeyEx API and verifies the return value was ERROR_SUCCESS. If it was, 1 is returned by RegDBKeyExist, otherwise, -1 is returned.

Using the following code in a test C++ project:

HKEY hKey;
UINT uiRes;

uiRes = RegOpenKeyEx(HKEY_LOCAL_MACHINE, _T("Software\\Wow6432Node\\Test"), REG_OPTION_NON_VOLATILE, KEY_ALL_ACCESS | KEY_WOW64_64KEY, &hKey);
printf("Opening Software\\Wow6432Node\\Test, WOW64_64KEY, result %d\n", uiRes);

yields the following output on a Windows 2008 machine even when the key exists:

Opening Software\Wow6432Node\Test, WOW64_64KEY, result 2

A result value of 2 is ERROR_FILE_NOT_FOUND, indicating the key was not found.

The same code returns 0 (ERROR_SUCCESS) on Windows 7 and 2008 R2, indicating a change in the operating system registry support.

Since this code is checking for a 32-bit key, it is recommended that 64-bit registry access not be enabled when checking for such a key.