The IUnknown class is the abstract class that all COM objects implement and all other ActiveX interfaces inherit.
You can create neither transient nor persistent instances of the IUnknown class.
For details about:
ActiveX interfaces, see "ActiveXInterface Class", earlier in this chapter
IDispatch subclass, see "IDispatch Class", earlier in this chapter
ActiveX automation servers, see "ActiveXAutomation Class", earlier in this chapter
ActiveX controls, see "
Importing ActiveX type libraries, see "