COM

As a side note, once interfaces are defined they should be fixed unless you are willing to re-compile all clients also. So if you want to alter the interface you should re-compile your client too. If you don't want to re-compile the client, then implement a new interface and have calls to your old interface redirect or forward to the method on the new interface. The redundant methods will just remain there, you can have them return errors if you want to indicate they shouldn't be called. Any new client, or client you don't mind re-compiling, will reference your new interface. This way all old and new clients still see the interfaces they were compiled against. You might be able to configure the interface forwarding for you automatically using the registry, it's been a while and back in the day interface forwarding was handled by the compiled and COM registration tools.

Bump .. Any thoughts on this anyone ?

I meant COM doesn't work easily side-by-side in the .net sense, but yes you can use the sxs framework to make side by side com assemblies. However re-reading the original question I think he was talking about registration free COM manifest files over standard registry-based registration. https://msdn.microsoft.com/en-us/library/fh1h056h(v=vs.110).aspx[^] But I think that only applies to .net clients, not the likes of VB.

You don't need to use side x side. The type library can be loaded as a file and the information you need extracted programmatically. But it won't be much fun. I would suggest that consider other ways to do this. I'm not sure whether the documentation is still around. MS want to discourage COM so I wouldn't be surprised if it had disappeared.

You don't need to call CoInitialize() again. You will need to check to see if the MFC interfaces are dual or not. If they are you can use then as if that are non-automation interfaces. I.e. just go obj->SomeMethod(); My guess is probably not, in which case you will have to use IDispatch->Invoke(...) which is a real pain. I'm sure you can find helper code out there on the Web.

If you have a C++ class class Z : public X, public Y { }; then you may be surprised to find that this is not a pointer to Y. Basic C++. But static_cast(this) is. You need a separate if(riid == IID_...){...} for each IID

Please do not use the forms for this sort of message, see http://www.codeproject.com/Messages/3122364/How-to-get-an-answer-to-your-question.aspx[^].

I faced the same error while accessing it from server. what i did is, changed the application pool identity in application pool on IIS. Identity should be the one which has administrator rights to use that application where it is installed. It worked fine after that. Hope it works for you too.

It's impossible to guess why that may be happening; maybe you should try re-installing the library. Alternatively, ask Nokia for assistance.