Re: Cygwin sysconf.cc

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Mar  2 12:45, Brian Inglis wrote:
> On 2022-03-02 01:25, Corinna Vinschen wrote:
> > Hi Brian,
> > 
> > On Mar  1 13:20, Brian Inglis wrote:
> > > Interested in a patch for sysconf.cc to return:
> > > 
> > >       _SC_TZNAME_MAX => TZNAME_MAX and
> > > _SC_MONOTONIC_CLOCK => _POSIX_MONOTONIC_CLOCK?
> > 
> > not sure I understand the question.  Both are already implemented.
> > 
> >    $ getconf -a | egrep '(TZNAME_MAX|MONOTONIC_CLOCK)'
> >    _POSIX_TZNAME_MAX                   6
> >    TZNAME_MAX                          undefined
> >    _POSIX_MONOTONIC_CLOCK              200809
> 
> Sorry, must have been looking at very *OLD* version online, as
> _SC_CLOCK_SELECTION and _SC_MONOTONIC_CLOCK were not defined.
> 
> Why did you not define _SC_TZNAME_MAX => _POSIX_TZNAME_MAX when you tweaked
> it?

Because it's wrong.  _POSIX_TZNAME_MAX is just a minimum value required
by POSIX, not the correct value to return for TZNAME_MAX.

> My rereading of the man and POSIX pages leads me to believe that for all
> known values of _SC_... the entries now showing {nsup, {c:0}} should be
> {cons, {c:-1L}} supported but undefined, and only out of range values for
> the parameter should be treated as {nsup, {c:-1L}}?

These are really not undefined, but not supported on Cygwin.  That's
why they return with EINVAL.  I see what you mean, though, let me think
about it.

while looking into this I see at least one obvious bug.  While adding
POSIX per-process timers in 2019 I added a valid DELAYTIMER_MAX value,
but I neglected to add this to sysconf.  I'm going to fix this.


Corinna