On Thu, Mar 20, 2025 at 5:29 PM Jonathan Wakely <jwak...@redhat.com> wrote:
> On Thu, 20 Mar 2025 at 16:16, Jonathan Wakely <jwak...@redhat.com> wrote:
> >
> > When using std::time_put to format a chrono value, we should imbue the
> > formatting locale into the stream. This ensures that when
> > std::time_put::do_put uses a ctype or __timepunct facet from the locale,
> > it gets the correct facets.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/bits/chrono_io.h (__formatter_chrono::_M_locale_fmt):
> > Imbue locale into ostringstream.
> > * testsuite/std/time/format/localized.cc: Check that correct
> > locale is used for call to time_put::put.
> > ---
> >
> > Now with a test that shows the bug independent of the PR117214 patches
> > to use std::time_put for %c formats.
> >
> > Tested x86_64-linux.
> >
> > libstdc++-v3/include/bits/chrono_io.h | 1 +
> > .../testsuite/std/time/format/localized.cc | 30 +++++++++++++++++++
> > 2 files changed, 31 insertions(+)
> >
> > diff --git a/libstdc++-v3/include/bits/chrono_io.h
> b/libstdc++-v3/include/bits/chrono_io.h
> > index c16b555df29..55ebd4ee061 100644
> > --- a/libstdc++-v3/include/bits/chrono_io.h
> > +++ b/libstdc++-v3/include/bits/chrono_io.h
> > @@ -1697,6 +1697,7 @@ namespace __format
> > char __fmt, char __mod) const
> > {
> > basic_ostringstream<_CharT> __os;
> > + __os.imbue(__loc);
> > const auto& __tp = use_facet<time_put<_CharT>>(__loc);
> > __tp.put(__os, __os, _S_space, &__tm, __fmt, __mod);
> > if (__os)
> > diff --git a/libstdc++-v3/testsuite/std/time/format/localized.cc
> b/libstdc++-v3/testsuite/std/time/format/localized.cc
> > index 393d0d200e4..437a4a011b2 100644
> > --- a/libstdc++-v3/testsuite/std/time/format/localized.cc
> > +++ b/libstdc++-v3/testsuite/std/time/format/localized.cc
> > @@ -13,6 +13,7 @@
> >
> > #include <chrono>
> > #include <format>
> > +#include <locale>
> > #include <stdio.h>
> > #include <testsuite_hooks.h>
> >
> > @@ -81,6 +82,35 @@ test_en()
> > }
> > }
> >
> > +void
> > +test_locale_imbued()
> > +{
> > + // Custom time_put facet which returns %b string for %Om
> > + struct TimePut : std::time_put<char>
> > + {
> > + iter_type
> > + do_put(iter_type out, std::ios_base& io, char_type fill, const tm*
> t,
> > + char format, char modifier) const override
> > + {
> > + if (format == 'm' && modifier == 'O')
> > + format = 'b';
> > + return std::time_put<char>::do_put(out, io, fill, t, format, 0);
> > + }
> > + };
> > +
> > + auto m = std::chrono::March;
> > +
> > + std::locale fr(ISO_8859(1,fr_FR));
> > + std::locale fr2(fr, new TimePut);
> > + auto s1 = std::format(fr2, "{:L%Om}", m);
> > + VERIFY( s1 == std::format(fr, "{:L}", m) );
> > +
> > + std::locale es(ISO_8859(1,es_ES));
> > + std::locale es2(es, new TimePut);
> > + auto s2 = std::format(es2, "{:L%Om}", m);
> > + VERIFY( s2 == std::format(es, "{:L}", m) );
> > +}
> > +
> > int main()
> > {
> > test_ru();
>
> It would help if I added the new test_locale_imbued() function to main
> so that it actually runs.
>
LGTM with that addition.
>
> Luckily it passes when I do that.
>
>
