Share via

IUnknown for MAPI (Compact 7)

  • Article

3/12/2014

The IUnknown interface for the Messaging Application Programming Interface (CE MAPI) manages the existence of a CE MAPI object through its own version of the AddRef, Release, and QueryInterface methods.

Methods in Vtable Order

IUnknown methods Description

MAPI IUnknown::QueryInterface

Returns a pointer to a specified interface.

MAPI IUnknown::AddRef

Increments the reference count for an interface on an object.

MAPI IUnknown::Release

Decrements the reference count for the calling interface on an object.

Remarks

All CE MAPI interfaces use COM, and therefore inherit IUnknown. However, to conserve memory on devices, the QueryInterface method of many CE MAPI interfaces returns an error indicating that the method is not implemented (E_NOTIMPL).

The AddRef and Release methods are always implemented on CE MAPI interfaces.

Requirements

Header

unknwn.h

See Also

Reference

MAPI Interfaces
IUnknown