My question is directed towards developers who are familiar with COM. I am currently writing my college thesis which is partially about Microsoft COM.
Please support your answers with facts as much as possible! Thank you.
Yes.
COM is still core to the way Windows works. Wherever a C-style api won't suffice, COM is the next step to expose an object model. And yes, Store apps are COM servers.
COM is native code, it adds very little overhead and is usable from practically any language that was ported to Windows.
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It is not essential anymore to have to know COM to write programs that run on Windows. Lots of work was done to wrap it and make it friendlier. The language projections in Store language runtimes are notable, there are very few traces of the underlying COM code visible. Relegating it to a status that's comparable to learning assembly language programming.