Update document for OpenKeyEx

Author: aisk

Doc/library/winreg.rst

@@ -299,8 +299,8 @@ This module offers the following functions:
    .. audit-event:: winreg.LoadKey key,sub_key,file_name winreg.LoadKey
 
 
-.. function:: OpenKey(key, sub_key, reserved=0, access=KEY_READ)
-              OpenKeyEx(key, sub_key, reserved=0, access=KEY_READ)
+.. function:: OpenKey(key, sub_key, reserved=0, access=KEY_READ, options=0)
+              OpenKeyEx(key, sub_key, reserved=0, access=KEY_READ, options=0)
 
    Opens the specified key, returning a :ref:`handle object <handle-object>`.
 
@@ -309,12 +309,20 @@ This module offers the following functions:
 
    *sub_key* is a string that identifies the sub_key to open.
 
-   *reserved* is a reserved integer, and must be zero.  The default is zero.
+   *reserved* is a reserved integer and should be zero.
+   If it is not zero, it will be treated as the options parameter.
+   You should use the *options* parameter directly instead,
+   this parameter is only included for compatibility reasons.
+   The default value is zero.
 
    *access* is an integer that specifies an access mask that describes the desired
    security access for the key.  Default is :const:`KEY_READ`.  See :ref:`Access
    Rights <access-rights>` for other allowed values.
 
+   *options* specifies the option to apply when opening the key.
+   Can be zero or one of the predefined
+   :ref:`REG_OPTION_* constants <hkey-constants>`.
+
    The result is a new handle to the specified key.
 
    If the function fails, :exc:`OSError` is raised.

PC/winreg.c

@@ -1411,7 +1411,9 @@ winreg.OpenKey -> HKEY
     sub_key: Py_UNICODE(accept={str, NoneType})
         A string that identifies the sub_key to open.
     reserved: int = 0
-        A reserved integer that must be zero.  Default is zero.
+        A reserved integer that be should zero.  If it is not zero,
+        it will be used as the options parameter for compatibility reasons.
+        Default is zero.
     access: REGSAM(c_default='KEY_READ') = winreg.KEY_READ
         An integer that specifies an access mask that describes the desired
         security access for the key.  Default is KEY_READ.