IMoniker::Inverse method (objidl.h)

Article
10/13/2021

Creates a moniker that is the inverse of this moniker. When composed to the right of this moniker or one of similar structure, the moniker will compose to nothing.

Syntax

HRESULT Inverse(
  [out] IMoniker **ppmk
);

Parameters

[out] ppmk

The address of an IMoniker pointer variable that receives the interface pointer to a moniker that is the inverse of this moniker. When successful, the implementation must call AddRef on the new inverse moniker. It is the caller's responsibility to call Release. If an error occurs, the implementation should set *ppmk to NULL.

Return value

This method can return the standard return values E_OUTOFMEMORY, as well as the following values.

Return code	Description
S_OK	The inverse moniker has been returned successfully.
MK_E_NOINVERSE	The moniker class does not have an inverse.

Remarks

The inverse of a moniker is analogous to the ".." directory in MS-DOS file systems; the ".." directory acts as the inverse to any other directory name, because appending ".." to a directory name results in an empty path. In the same way, the inverse of a moniker typically is also the inverse of all monikers in the same class. However, it is not necessarily the inverse of a moniker of a different class.

The inverse of a composite moniker is a composite consisting of the inverses of the components of the original moniker, arranged in reverse order. For example, if the inverse of A is Inv( A ) and the composite of A, B, and C is Comp( A, B, C ), then

Inv( Comp( A, B, C ) ) is equal to Comp( Inv( C ), Inv( B ), Inv( A ) ).

Not all monikers have inverses. Most monikers that are themselves inverses, such as anti-monikers, do not have inverses. Monikers that have no inverse cannot have relative monikers formed from inside the objects they identify to other objects outside.

Notes to Callers

An object that is using a moniker to locate another object usually does not know the class of the moniker it is using. To get the inverse of a moniker, you should always call IMoniker::Inverse rather than the CreateAntiMoniker function, because you cannot be certain that the moniker you're using considers an anti-moniker to be its inverse.

The Inverse method is also called by the implementation of the IMoniker::RelativePathTo method, to assist in constructing a relative moniker.

Notes to Implementers

If your monikers have no internal structure, you can call the CreateAntiMoniker function in to get an anti-moniker in your implementation of IMoniker::Inverse. In your implementation of IMoniker::ComposeWith, you need to check for the inverse you supply in the implementation of Inverse.

Implementation-specific Notes

Implementation	Notes
Anti-moniker	This method returns MK_E_NOINVERSE and sets *ppmk to NULL.
Class moniker	This method returns an anti-moniker (that is, the results of calling CreateAntiMoniker).
File moniker	This method returns an anti-moniker (that is, the results of calling CreateAntiMoniker).
Generic composite moniker	This method returns a composite moniker that consists of the inverses of each of the components of the original composite, stored in reverse order. For example, if the inverse of A is Inv( A ), the inverse of the composite of A, B, and C is Comp(Inv( C ), Inv( B ), Inv( A ) ).
Item moniker	This method returns an anti-moniker (that is, the results of calling CreateAntiMoniker).
OBJREF moniker	This method returns an anti-moniker (that is, the results of calling CreateAntiMoniker).
Pointer moniker	This method returns an anti-moniker (that is, the results of calling CreateAntiMoniker).
URL moniker	This method returns MK_E_NOINVERSE and sets *ppmk to NULL.

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	objidl.h