> On other systems, trying to invoke the system calls manually and bypassing the C wrapper opens you up into undefined behavior
It opens you up to a bit more of behavior changing in the future, but just a tiny bit more. No need to make a big deal out of it. It's a very normal thing in software. Nobody is going to promise you a perfect stable interface to rely on forever, not even Linux. But syscalls are actually pretty easy to keep up with, they change slowly, and it's easy to detect kernel version and choose appropriate wrappers to use with very little extra code.
OS X problem is its own thing. Apple making breaking changes is not a new thing. I use an Apple laptop super rarely and still got fed up with breaking changes, even not upgrading past 13.6 at the moment.
Can any of the downvoters explain disagreement? I actually maintain a small Go library of syscall wrappers for Linux and BSDs and don't get why people are spreading FUD about it, as if it's a minefield. It's not, it's a non issue at all even for someone working independently on it. I find it even easier than dealing with all the libc crap on those systems.
Windows syscall numbers change with every service pack release (see https://j00ru.vexillium.org/syscalls/nt/64/ for an incomplete table), and the interfaces themselves are not guaranteed to be stable in any way. ntdll is the only reasonable way to make syscalls on Windows. Trying to build your own syscall code on Windows is fragile and unmaintainable.
Linux maintains stable syscall interfaces. BSDs don't guarantee it, but generally don't change much. But macOS and Windows can and will change their interfaces.
It opens you up to a bit more of behavior changing in the future, but just a tiny bit more. No need to make a big deal out of it. It's a very normal thing in software. Nobody is going to promise you a perfect stable interface to rely on forever, not even Linux. But syscalls are actually pretty easy to keep up with, they change slowly, and it's easy to detect kernel version and choose appropriate wrappers to use with very little extra code.
OS X problem is its own thing. Apple making breaking changes is not a new thing. I use an Apple laptop super rarely and still got fed up with breaking changes, even not upgrading past 13.6 at the moment.