One of mingw{,-w64}'s major contributions is a gcc-compatible replacement set of headers and import libraries, instead of using the Windows SDK or MSVC versions

One of mingw{,-w64}'s major contributions is a gcc-compatible replacement set of headers and import libraries, instead of using the Windows SDK or MSVC versions. These work great most of the time, but if you start hooking deeply into windows, you realise they are a little bit outdated or incompatible. e.g. I get a lot of errors like #warning COM interfaces layout in this header has not been verified. #warning COM interfaces with incorrect layout may not work at all. #pragma message: Interface Ifoo has unverified layout. in COM code, and some ATL things it is unable to build at all.