How do you access function definitions like Intellisense does?

I need to get C++ definitions programmatically for windows api functions. An example: If I need the definition for CloseHandle I want:

BOOL WINAPI CloseHandle(
  _In_ HANDLE hObject
);

I currently have a way to do this but it is not efficient. The current way I do this programmatically is by parsing a Bing search, retrieving the msdn page containing the function definition and extracting it. When I have to do a couple hundred to a couple thousand requests, it gets quite time consuming.

I asked on here because I figured someone has worked with intellisense or object browser while creating an extension. A solution using C# or .NET would be preferred, I just need pointed in the right direction. Thanks!!