Analysis of information sources in references of the Wikipedia article "Universally unique identifier" in English language version.
You reference an interface at run time with a globally unique interface identifier (IID). This IID, which is a specific instance of a globally unique identifier (GUID) supported by COM, allows a client to ask an object precisely whether it supports the semantics of the interface, without unnecessary overhead and without the confusion that could arise in a system from having multiple versions of the same interface with the same name.
A listing of the CATIDs and the human-readable names is stored in a well-known location in the registry.
