Returns state information about the innermost open parent undo unit.
HRESULT GetOpenParentState(
DWORD* pdwState //Pointer to state information
);
If there is an open parent unit, this method calls IOleParentUnit::GetParentState.
If the undo manager is disabled, it should fill the pdwState parameter with UAS_BLOCKED and return S_OK.
When checking for a normal state, use the UAS_MASK value to mask unused bits in the pdwState parameter to this method for future compatibility. For example:
Windows NT: Use version 4.0 or later. New for OC96.
Windows: Use Windows 95 or later. New for OC96.
Windows CE: Unsupported.
Header: Declared in ocidl.h.