Linux is an unusual platform in that it allows you to call into it via assembly. Most other platforms require you to go through libc to do so. It's not really in Rust's hands.
This is not unusual at all. Windows allowed it for years before Linux came along. It was also true of some other *nix systems - IIRC, Ultrix (DEC) allowed this, and so did Dynix (Sequent).
*BSD allows it too, or used as of 2022.
What is unusual about Linux is that it guarantees a syscall ABI, meaning that if you follow it, you can make a system call "portably" across "any" version of Linux.
Sure, I’m speaking about platforms that are relevant today, not historical ones. Windows, MacOS, {Free,Open,Net}BSD, Solaris, illumos, none of these do.
It's quite easy to find out the actual situation on this since Go decided to do it their way. Last I checked, OpenBSD is the only OS where they go through libc, but I haven't really kept up.
Yep, in 2022 it finally started using libc on *BSD too.
But ... there's a difference between being able to do direct syscalls via asm, and them being portable across kernel versions, which is what this subthread was about.
Granted, most people want version portability, but still on a technical level, it's not the same thing.
No, my comment was about what APIs a platform considers to be their stable, external API. That you can technically call them anyway (except for ones like OpenBSD that actively check and prevent you) doesn't mean you're not doing something unsupported.
