is adding new private symbols to libc frowned upon?

[Kyle Evans]

On Sat, Dec 22, 2018 at 12:42 AM Konstantin Belousov
<kostikbel at gmail.com> wrote:
>
> On Sat, Dec 22, 2018 at 04:38:52AM +0300, Yuri Pankov wrote:
> > Essentially, I need the __collate_equiv_value symbol to be visible to
> > libregex for the changes in https://reviews.freebsd.org/D18531.  Is the
> > following change OK (it works, at least), or should try to avoid that?
> >
> > --- a/lib/libc/locale/Symbol.map
> > +++ b/lib/libc/locale/Symbol.map
> > @@ -212,6 +212,7 @@ FBSD_1.3 {
> >  FBSDprivate_1.0 {
> >         _PathLocale;
> >         __detect_path_locale;
> > +       __collate_equiv_value;
> >         __collate_load_error;
> >         __collate_range_cmp;
> >  };
> >
> Then libregex must always match the installed libc.
>
> I looked at the the libregex/Makefile and my question is, what is the
> difference between exports from libc/regex vs. libregex.  Can libregex
> become ELF filter for libc ?
>

libregex is going to be getting more complicated [1] after a couple
more exp-runs. I can possibly re-work it to make a filter work
(perhaps?), but I'm not sure how badly that will impact the
performance of libc regex.

[1] https://reviews.freebsd.org/D12935