RegOpenKeyEx info Overview Group

The RegOpenKeyEx function opens the specified key.

LONG RegOpenKeyEx(

HKEY hKey,

// handle of open key

LPCTSTR lpSubKey,

// address of name of subkey to open

DWORD ulOptions,

// reserved

REGSAM samDesired,

// security access mask

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

lpSubKey

Points to a null-terminated string containing the name of the subkey to open. If this parameter is NULL or a pointer to an empty string, the function will open a new handle of the key identified by the hKey parameter. In this case, the function will 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:

Value	Meaning
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

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

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

HKEY hKey,	// handle of open key
LPCTSTR lpSubKey,	// address of name of subkey to open
DWORD ulOptions,	// reserved
REGSAM samDesired,	// security access mask
PHKEY phkResult	// address of handle of open key
);

RegOpenKeyEx info Overview Group

Parameters

Return Values

Remarks

See Also