On Thu, Apr 2, 2020 at 1:19 PM Michael Kerrisk (man-pages) <mtk.manpages@xxxxxxxxx> wrote: > > There is documentation in: > > - include/linux/posix-clock.h > > - Documentation/driver-api/ptp.rst (explicitly states that EOPNOTSUPP > > should be returned) > > (Is this a reference to the tack that I tweaked your patch to change > EOPNOTSUPP to ENOTSUP?) Oh not at all, I hadn't noticed your patch. I just wrote that sentence to point to ptp.rst as a spec of sorts for that particular behavior addressed by this patch. I never know which one to use of EOPNOTSUPP or ENOTSUP since they have the same value (in userspace) but POSIX.1 says they shouldn't. I suppose for man2 it makes sense to pick one, whereas man3p has to make the distinction. For what it's worth, man2/ has 29 mentions of EOPNOTSUPP (value of 95 on x86) and 8 mentions of ENOTSUP (with a value 524). In the kernel sources, it's 6324 vs 1512. But note that in kernel code, EOPNOTSUPP has a value of 95 (on x86 anyway, it is arch dependent), whereas ENOTSUP is 524. Glibc is the one that defines ENOTSUP to EOPNOTSUPP. So if we had to pick one for man2/ (and man7), I'd argue for EOPNOTSUPP, for consistency with kernel code, now that I look at it in more details. > > - include/uapi/linux/ptp_clock.h > > ... it's a bit of a stretch to call any of those documentation, since > they don't really describe the concept of a dynamic POSIX clock > device. > > > > > (IEEE 1588 PTP is the canonical user of these dynamic clock devices) > > > > Would you want to refer to any of these from the man page? > > See above. I would be happy to add a 2 or 3 sentence note to the page > that briefly describes the concept of a POSIX clock. Would you be able > to come up with something? I'll try, but I've never used them, so I'm not convinced I can capture the concept clearly. Thanks, Eric
