Comment by sedatk
20 hours ago
No. On NT, kernel ABI isn't defined by the syscalls but NTDLL. Win32 and all other APIs are wrappers on top of NTDLL, not syscalls. Syscalls are how NTDLL implements kernel calls behind the scenes, it's an implementation detail. Original point of the thread was about Win32, UWP and other APIs that build a new layer on top of NTDLL.
I argue that NT doesn't break its kernel ABI.
NTDLL APIs are very stable[0] and you can even compile and run x86 programs targeting NT 3.1 Build 340[1] which will still work on win11.
[0] as long as you don't use APIs they decided to add and remove in a very short period (longer read: https://virtuallyfun.com/2009/09/28/microsoft-fortran-powers...)
[1] https://github.com/roytam1/ntldd/releases/tag/v250831
macOS and iOS too — syscalls aren’t stable at all, you’re expected to link through shared library interfaces.