When is registering a Type Library necessary?

Question

For example, if writing a shell extension, is it necessary to register the typelib with CComModule::RegisterServer (i.e., I'm wondering if calling it with FALSE will cause some issues).

Answer 1

In general, it's fine to say FALSE unless you need a typelib because someone is going to be calling your IDispatch implementation. For most shell extensions I don't think you need a typelib.

Answer 2

Sorry, misunderstood the question.

Answer 3

Hardly ever. In theory typelibs would be used by IDEs that wan't to display lists of properties and methods on an object. OleSpy++ or whatever the tool is called can use typelibs to generate quite a lot of important information about the ActiveX

In MSVC you can use #import on a ActiveX with embedded typelib and header files describing the interfaces and types will be automatically generated.

When dealing with well-known interfaces - published in the platform sdk - or if the header files are already supplied for C & C++ bindings, then typelibs are a tad useless.

Even when used from script languages, IDispatchEx now seems to be preferred as a discovery mechanism for the IDE or code to query an IDispatch supporting object at runtime for its methods.