Windows standard C and C++ ABI is stable since 2017. So the last 3 releases of the Visual C Compiler and C runtime hasn't changed the ABI. However Windows also

Windows standard C and C++ ABI is stable since 2017. So the last 3 releases of the Visual C Compiler and C runtime hasn't changed the ABI. However Windows also has a lower level system API / ABI i.e. Win32 that's always stable all the way to Win 95. WinSXS sometimes helps for certain legacy apps too. This allows apps using different C libraries to work together. Win32 contains everything about the OS interface. Creating windows, drawing things, basic text, allocating pages from the OS, querying users, getting info about files is all stable. Win32 is the lower level of the C library. There is also a better separation of the functions in different DLLs. Win32 has multiple DLLs that has different jobs and they are mostly orthogonal. Kernel32 contains core almost system call stuff. Shell32 contains interactions with the OS shell i.e. creating windows, message boxes, triggering different UIs. The surrounding libraries like DirectX / DirectPlay / DirectWrite that are also used by the games are also part of the system libs starting from 7. They are also stable. On Linux world there is no separation of the system level libraries and normal user libraries. Glibc is just another library that one depends on. It contains the entire lower level interface to kernel, all the network stuff and POSIX user access stuff. It also contains a component that has no job in a C library: the dynamic executable loader. Unlike Windows on the Unix systems the C library is at the lowest level and Glibc being the default libc for Linux and making itself the default provider of the dynamic executable loader makes writing stable ABI almost impossible. Since other libraries depend on Glibc and executables depend on Glibc's dynamic loader everything is affected by the domino effect.