RegOpenKey info  Overview  Group

The RegOpenKey function opens the specified key. This function is provided for compatibility with Windows version 3.1. Win32-based applications should use the RegOpenKeyEx function.

LONG RegOpenKey(

HKEY hKey,	// handle of open key
LPCTSTR lpSubKey,	// address of name of subkey to open
PHKEY phkResult	// address of handle of open key
);

Parameters

hKey

Identifies a currently open key or any of the following predefined reserved handle values:

HKEY_CLASSES_ROOT
HKEY_CURRENT_CONFIG
HKEY_CURRENT_USER
HKEY_LOCAL_MACHINE
HKEY_USERS
Windows NT only: HKEY_PERFORMANCE_DATA 
Windows 95 only: HKEY_DYN_DATA 

The key opened by the RegOpenKey function is a subkey of the key identified by hKey.

lpSubKey

Points to a null-terminated string containing the name of the key to open. This key must be a subkey of the key identified by the hKey parameter. If this parameter is NULL or a pointer to an empty string, the function returns the same handle that was passed in.

phkResult

Points to a variable that receives the handle of the opened key.

Return Values

If the function succeeds, the return value is ERROR_SUCCESS.

If the function fails, the return value is a nonzero error code defined in WINERROR.H. You can use the FormatMessage function with the FORMAT_MESSAGE_FROM_SYSTEM flag to get a generic description of the error.

Remarks

The RegOpenKey function uses the default security access mask to open a key. If opening the key requires a different mask, the function fails, returning ERROR_ACCESS_DENIED. An application should use the RegOpenKeyEx function to specify an access mask in this situation.

Unlike the RegCreateKey function, RegOpenKey does not create the specified key if the key does not exist in the database.

See Also

RegCloseKey, RegCreateKey, RegCreateKeyEx, RegDeleteKey, RegOpenKeyEx