For C: both platform have been EXTREMELY compatible over the years. They probably both treat breakage as bug. This is a must given the fundamental APIs are defi

For C: both platform have been EXTREMELY compatible over the years. They probably both treat breakage as bug. This is a must given the fundamental APIs are defined in term of C headers, and must remain compatible. Even for C++: gcc has been mostly compatible, but not unreasonably so. MSVC was traditionally not at all, but has recently been for 2 or 3 major versions in a row. I think MSVC will eventually break it again though, but at least they break it way less often than before (and breaking can also have advantages).