Before 2000, I have been using ANSI C for Windows programming. Later I changed to C++ and MFC, then to Delphi, and nowadays I prefer C#, but I'm curious if it is still possible to use plain C to access every API of the modern editions of Windows.
For example, even COM/OLE objects can be dealt with from C.
The Windows APIs list is described here.
Most of the APIs are C-based (structures and functions). However, few are C++ based (classes):