| Platform SDK: MAPI |
The IID structure is a GUID structure used to describe an identifier for a MAPI interface.
An IID structure is used to uniquely identify a MAPI interface and to associate a particular interface with an object. For example, when a client calls IMAPISession::OpenEntry to open a folder, the client sets the lpInterface parameter to point to an IID representing the IMAPIFolder interface. MAPI defines the IMAPIFolder IID to be IID_IMAPIFolder. IID structures are also used to uniquely identify OLE interfaces.
All of the specific IID structures for the MAPI interfaces are defined in the MAPIGUID.H header file.