**RegQueryValueEx retrieves the type and data of a specified value associated with an open registry key.**
### Parameters
- **hKey**
A handle to an open registry key, or one of the following predefined reserved handle values:
- HKEY_CLASSES_ROOT
- HKEY_CURRENT_CONFIG
- HKEY_CURRENT_USER
- HKEY_LOCAL_MACHINE
- HKEY_USERS
- Windows NT: HKEY_PERFORMANCE_DATA
- Windows 95 and Windows 98: HKEY_DYN_DATA
- **lpValueName**
A pointer to a null-terminated string that specifies the name of the value to query.
If lpValueName is NULL or an empty string (" "), this function retrieves the type and data of the unnamed or default value for the key.