Generate correct IIDs for parametrized interfaces #4
Description
For parametric interface types such as AsyncOperationCompletedHandler<TResult>, the SDK header files include definitions of all used specializations of the generic parameter, together with IIDs. These IIDs are deterministic and I was wondering where they are coming from, so I found this blog post, especially the section on "Generic Interfaces" is helpful. The key is the function RoGetParameterizedTypeInstanceIID.
I will probably add that metadata API to my winapi PR, but since the idea was to generate the bindings with some F# or C# program, it's not that important. Some comments also indicate that the API might only be usable from within a Windows Store App, so of course the best thing would be to know the algorithm used to generate those IIDs (see also the last paragraph of the blog post: The somewhat problematic thing about this is this might be difficult to include in a compiler, because the APIs are only available on Win8, so there's no way to generate the GUIDs from a older version of Windows. It'd be nice if Microsoft provided information on how those GUIDs are constructed so other tools that run on other Windows platforms can cross-build for Win8.)