Re: [PATCH] timeout: support sub-second timeouts on macOS

[Pádraig Brady]

On 09/11/2020 01:33, Jim Meyering wrote:
> On Sun, Nov 8, 2020 at 1:26 PM Pádraig Brady <P@draigbrady.com> wrote:
> > On 08/11/2020 18:52, Jim Meyering wrote:
> > > On Sat, Nov 7, 2020 at 2:08 PM Pádraig Brady <P@draigbrady.com> wrote:
> > > > * m4/jm-macros.m4: Check for setitimer.
> > > > * src/timeout.c: Use setitimer if timer_settime is not available.
> > > > * NEWS: Mention the improvement.
> > >
> > > Thanks!  The patch looks fine and I confirmed it works.
> > > I encountered a few hurdles to make everything build using Xcode-12.1:
> > > - I had brew's bison-2.3, but that didn't work (failed to create
> > > lib/parse-datetime.c). fixed by installing bison-3.7.3
> > > - compile error due to gnulib's lib/mgetgroups.c. I worked around it
> > > by adding a gross cast. I doubt that's proper, but I haven't dug
> > > enough to say more.
> > >
> > > diff --git a/lib/mgetgroups.c b/lib/mgetgroups.c
> > > index 3377d7bb2..a27da05e5 100644
> > > --- a/lib/mgetgroups.c
> > > +++ b/lib/mgetgroups.c
> > > @@ -93,7 +93,7 @@ mgetgroups (char const *username, gid_t gid, gid_t **groups)
> > >              int last_n_groups = max_n_groups;
> > >
> > >              /* getgrouplist updates max_n_groups to num required.  */
> > > -          ng = getgrouplist (username, gid, g, &max_n_groups);
> > > +          ng = getgrouplist (username, gid, (int *) g, &max_n_groups);
> > >
> > >              /* Some systems (like Darwin) have a bug where they
> > >                 never increase max_n_groups.  */
> > >
> > > - finally, I normally configure with --enable-gcc-warnings, but that
> > > evokes the attached errors, so I got past that by building with
> > > WERROR_CFLAGS=
> >
> > Thanks for all the checking.
> > I just used a dist tarball to check.
> >
> > Re getgrouplist, that was looked extensively at in:
> > https://bugs.gnu.org/20923
> > Is the __GNUC__ define used there different for your case?
>
> Yes, this version of xcode declares itself as GCC 4.2.1:
> [Two other solutions: use GCC or do not to use --enable-gcc-warnings]
>
> $ :|gcc -E -dD -|grep GNUC
> #define __GNUC__ 4
> #define __GNUC_MINOR__ 2
> #define __GNUC_PATCHLEVEL__ 1
> #define __GNUC_STDC_INLINE__ 1

The attached disables the mgetgroups warning for any __clang__.
Does that address the issue directly?

cheers,
Pádraig

mgetgroups-clang.diff
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