Given a COM DLL, extract all classes CLSID and corresponding interface name

Question

My question is similar to Getting CLSID for a DLL file?, I think.

I have a directory with some DLLs, each one implementing one or more COM interfaces. I would like to ge

Answer 1

Few caveats to Ben Voigt's answer: not every COM DLL has a typelib. In your case, it seems, it does; but that's not a requirement. The only rock-solid requirement is that the DLL exports the function DllGetClassObject(), where you pass a CLSID and get back an object factory.

You could load the library and call DllGetClassObject for every registered CLSID on the system (scan the registry under HKCR\CLSID for the list of those). The ones where you get a valid object back are the ones that the DLL supports. Now, in theory, it's not even a requirement that the CLSIDs the DLL supports are registered; I can envision a DLL that implements private object classes that only the intended client knows about and no one else should. But this is a very, very exotic scenario; for one thing, the regular COM mechanism of looking up the DLL path by the CLSID will break for those. The client would have to load the DLL directly.

You could also scan the registry for the CLSID's where the DLL under consideration is registered as InprocServer32; this, again, will break in case of private classes. You can do a registry search in regedit, search in data. Also, you'd have to deal with filename case issues, short vs. long names, hardlinks, environment variable substitution and so on. So I would not recommend it.

EDIT: just thought of another way. Download Regmon, run it, and call regsvr32 on the DLL. Then watch what CLSID's are touched.