GNU/Linux isn't the only system out there, POSIX last update was in 2024 (when C requirement got upgraded to C17), and yes some parts of it are outdated in modern platforms, especially Apple, Google, Microsoft OSes and Cloud infrastructure.

Still, who supports POSIX is expected to have a C compiler available if applying for the OpenGroup stamp.

> GNU/Linux isn't the only system out there, [...]

Yes? I'm especially keen on the project to make just 'Linux' without any Gnu components. Jokes aside, yes, other operating systems exist.

> [...] and yes some parts of it are outdated in modern platforms, especially Apple, Google, Microsoft OSes and Cloud infrastructure.

Well, also on modern hardware in general. POSIX's idea about storage abstractions don't gel well with modern hardware. Well, not just modern hardware: atime has been cast aside since time immemorial. But lots of the other ideas are also dropping by the wayside.

In practice, we get something like 'POSIX-y' or 'close-enough-to-POSIX', which doesn't get a stamp from OpenGroup. I think Linux largely falls in that boat.

But regardless of that distinction, a C compiler is very much part of the informal 'close-enough-to-POSIX' class.

It's a bit of a shame that Unix has retarded operating system research for so long. Fortunately, the proliferation of virtual machines and hypervisors have re-invigorated the field. Just pretend that your hypervisor is your nano-kernel and your VMs are your processes. No need to run a full on Linux kernel in your VM, you can just have enough code running for your webserver or database etc, no general kernel needed. See eg https://mirage.io/