The system call numbers of all the unixlikes are bitwise packed into a single number. There is exactly one of those columns which is stable: the Linux one. Everything else is not part of the binary interface of their respective operating systems.
I've written about how Linux is special in this regard:
Program to the API rather than the ABI.
When we see benefits, we change the ABI
more often than the API.
I have altered the ABI.
Pray I do not alter it further.
-- Theo de Raadt
Case in point:
https://github.com/jart/cosmopolitan/blob/master/libc/sysv/s...
The system call numbers of all the unixlikes are bitwise packed into a single number. There is exactly one of those columns which is stable: the Linux one. Everything else is not part of the binary interface of their respective operating systems.
I've written about how Linux is special in this regard:
https://www.matheusmoreira.com/articles/linux-system-calls
It's a neat hack but I'm afraid it's in grave danger of falling victim to the Darth Vader of OS ABI stability.
https://lwn.net/Articles/806870/