Identifying and Registering an Object Class
A major strength of COM is the use of globally unique identifiers to essentially name each object class that exists, not only on the local computer but universally across all computers and all platforms. The algorithm that guarantees this is encompassed in the COM Library function CoCreateGuid, as described in Chapter 3. An object implementor must obtain a GUID to assign to the object server as its CLSID for each implemented class.