IOleParentUndoUnit::Close method (ocidl.h)

Article
07/27/2022

Closes the specified parent undo unit.

Syntax

HRESULT Close(
  [in] IOleParentUndoUnit *pPUU,
  [in] BOOL               fCommit
);

Parameters

[in] pPUU

An IOleParentUndoUnit pointer to the currently open parent unit to be closed.

[in] fCommit

Indicates whether to keep or discard the unit. If TRUE, the unit is kept in the collection. If FALSE, the unit is discarded. This parameter is used to allow the client to discard an undo unit under construction if an error or a cancellation occurs.

Return value

This method returns S_OK on success. Other possible return values include the following.

Return code	Description
S_FALSE	The parent undo unit did not have an open child and it was successfully closed.
E_INVALIDARG	If pPUU does not match the currently open parent undo unit, then implementations of this method should return E_INVALIDARG without changing any internal state unless the parent unit is blocked.

Remarks

A parent undo unit knows it is being closed when it returns S_FALSE from this method. At that time, it should terminate any communication with other objects which may be giving data to it through private interfaces.

Notes to Callers

An error return indicates a fatal error condition.

The parent unit or undo manager must accept the undo unit if fCommit is TRUE.

Notes to Implementers

To process a close request, a parent undo unit first checks to see if it has an open child unit. If it does not, it returns S_FALSE.

If it does have a child unit open, it calls the IOleParentUndoUnit::Close method on the child. If the child returns S_FALSE, then the parent undo unit verifies that pPUU points to the child unit, and closes that child undo unit. If the child returns S_OK then it handled the close internally and its parent should do nothing.

If the parent unit is blocked, it should check the pPUU parameter to determine the appropriate return code. If pPUU is pointing to itself, then it should return S_FALSE.

Otherwise, it should return S_OK; the fCommit parameter is ignored; and no action is taken.

If pPUU does not match the currently open parent undo unit, then implementations of this method should return E_INVALIDARG without changing any internal state. The only exception to this is if the unit is blocked.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	ocidl.h

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