Whether POSIX calls should be called system calls

Dan Bernstein brnstnd at kramden.acf.nyu.edu
Mon Oct 15 04:07:52 AEST 1990


I think of POSIX calls as system calls, even if they aren't implemented
inside the kernel. There's no way for a conforming program to tell
whether something's a kernel call or not; and POSIX calls feel like
system calls in every other way (they're guaranteed to be around and
work correctly, no matter what libraries you have).

Any differing opinions? Followups to comp.unix.misc.

In article <1990Oct14.122854.17433 at virtech.uucp> cpcahil at virtech.UUCP (Conor P. Cahill) writes:
> In article <21628:Oct1400:12:2990 at kramden.acf.nyu.edu> brnstnd at kramden.acf.nyu.edu (Dan Bernstein) writes:
> >and BSD
> >stat() might not be implemented inside the kernel either. (It can be
> >written in terms of lstat() and readlink(), for example.)
> Actually, to maintain binary compatibility with earlier code it has
> to be implemented in the kernel.

Grasping at straws. Binary compatibility is not a requirement for a UNIX
system. It's hardly even important for most people. I stand by my
statement.

---Dan



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