C++ 从 64 位应用程序读取 SOFTWARE\WOW6432 中的注册表项

Question

I've got some 32-bit C++ code to read a Key/Value pair from the Registry as follows:

    // Get a handle to the required key
    HKEY    hKey;
    if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, "Software\\MyKey", 0, KEY_READ, &hKey) == ERROR_SUCCESS)
    {
        // Look up the value for the key
        bOK = (RegQueryValueEx(hKey, szKey, NULL, NULL, (PBYTE)szValue, &dwMax) == ERROR_SUCCESS);
        
        // Release the handle
        RegCloseKey(hKey);
    }

As it's a 32-bit app it reads from SOFTWARE\WOW6432Node\MyKey

This was working fine until I ported the app to 64-bit, so it now reads from SOFTWARE\MyKey.

My installer won't let me put entries into both the 32-bit and 64-bit parts of the Registry, so I need the 64-bit app to go on getting its data from WOW6432Node.

Does anyone know how to do this?

Many thanks Tony Reynolds

Answer 1

As documented under 32-bit and 64-bit Application Data in the Registry :

The KEY_WOW64_64KEY and KEY_WOW64_32KEY flags enable explicit access to the 64-bit registry view and the 32-bit view, respectively. For more information, see Accessing an Alternate Registry View .

The latter link explains that

These flags can be specified in the samDesire d parameter of the following registry functions:

• RegCreateKeyEx
• RegDeleteKeyEx
• RegOpenKeyEx

The following code accomplishes what you are asking for:

// Get a handle to the required key
HKEY    hKey;
if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, "Software\\MyKey", 0, KEY_READ | KEY_WOW64_32KEY, &hKey) == ERROR_SUCCESS)
{
    // ...
}