COM objects must be unique throughout the world

The whole world? Come on! This may seem like an exaggeration at first, but consider the Internet to be a worldwide network. Even if you're working on a single computer, COM must handle the possibility. Uniqueness is the issue. In C++ all classes are handled unequivocally by thecompiler. The compiler can see the class definition for every class used in a program and match up all references to it to make sure they conform to the class exactly. The compiler can also guarantee that there is only one class of a given name. In COM there must be a good way to get a similarly unequivocal match. COM must guarantee that there will only be one object of a given name even though the number of objects available on a worldwide network is huge. This problem is solved by creating a concept called a GUID.