Opens the specified registry key.

LONG RegOpenKeyEx(
    HKEY hKey,
    LPCTSTR lpSubKey,
    DWORD ulOptions,
    REGSAM samDesired,
    PHKEY phkResult
);

Parameters

hKey

Handle to a currently open key or any of these predefined reserved handle values:

HKEY_CLASSES_ROOT HKEY_CURRENT_CONFIG HKEY_CURRENT_USER HKEY_LOCAL_MACHINE HKEY_USERS HKEY_PERFORMANCE_DATA

lpSubKey

Pointer to a null-terminated string that contains the name of the subkey to open. If this parameter is NULL or a pointer to an empty string, the call opens a new handle to the key identified by the hKey parameter. In this case, the call does not close the handles previously opened.

ulOptions

Reserved; must be zero.

samDesired

Specifies an access mask that describes the desired security access for the new key. This parameter can be a combination of the following values:

KEY_ALL_ACCESS	Combination of KEY_QUERY_VALUE, KEY_ENUMERATE_SUB_KEYS, KEY_NOTIFY, KEY_CREATE_SUB_KEY, KEY_CREATE_LINK, and KEY_SET_VALUE access.
KEY_CREATE_LINK	Permission to create a symbolic link.
KEY_CREATE_SUB_KEY	Permission to create subkeys.
KEY_ENUMERATE_SUB_KEYS	Permission to enumerate subkeys.
KEY_EXECUTE	Permission for read access.
KEY_NOTIFY	Permission for change notification.
KEY_QUERY_VALUE	Permission to query subkey data.
KEY_READ	Combination of KEY_QUERY_VALUE, KEY_ENUMERATE_SUB_KEYS, and KEY_NOTIFY access.
KEY_SET_VALUE	Permission to set subkey data.
KEY_WRITE	Combination of KEY_SET_VALUE and KEY_CREATE_SUB_KEY access.

phkResult

Pointer to a variable that receives a handle to the opened key. When you no longer need the returned handle, call RegCloseKey to close it.

Remarks

Unlike RegCreateKeyEx, RegOpenKeyEx does not create the specified key if the key does not exist in the registry.

Return Values

ERROR_SUCCESS

Success.

A nonzero status code defined in RTWIN32.H.

Failure. For extended error information, see GetLastError

Requirements

Note

This function operates in the real-time portion of your application.

See Also

RegCloseKey, RegCreateKeyEx, RegDeleteKey, iwin32 API, iwin32 Overview