> Works nicely on Linux where the syscall interface is explicitly stable, but on many (most?) other platforms this is not the case.

There is a footnote on this saying as much:

> 3. Where “syscall” means “the lowest level primitive available”. On Linux, it’s always actual syscalls. On Windows, that’s usually NT. On macOS, it’s usually the syscall-wrapper subset of libc because you’re forced to link libc and it’s not quite as open as Linux (although there is a rich “undocumented” set of APIs and syscalls that are very interesting).