On Thu, 23 Jul 2026 at 12:03, Tomasz Kaminski <[email protected]> wrote:
>
>
>
> On Thu, Jul 23, 2026 at 12:47 PM Jonathan Wakely <[email protected]> wrote:
>>
>> On Wed, 01 Jul 2026 at 14:33 +0200, Tomasz Kaminski wrote:
>> >On Wed, Jul 1, 2026 at 2:15 PM Anlai Lu <[email protected]> wrote:
>> >
>> >> Add __detail::__chrono_write which formats a chrono object into a
>> >> stack buffer via std::format_to_n with _S_empty_fs(), then writes
>> >> through __ostream_insert. A non-type template parameter _BufSize
>> >> (default 128) allows per-type buffer tuning. Each _BufSize is the
>> >> smallest power of two that accommodates the longest possible formatted
>> >> output for that type, including error cases. All chrono operator<<
>> >> overloads that previously used std::format, std::vformat, or
>> >> basic_stringstream now use this helper.
>> >>
>> >> libstdc++-v3/ChangeLog:
>> >>
>> >> * include/bits/chrono_io.h (__formatter_chrono::_S_empty_fs):
>> >> Make public.
>> >> (__detail::__chrono_write): New function template.
>> >> (operator<<): Use __chrono_write consistently for all chrono
>> >> types.
>> >>
>> >> Signed-off-by: Anlai Lu <[email protected]>
>> >> ---
>> >> libstdc++-v3/include/bits/chrono_io.h | 244 ++++++--------------------
>> >> 1 file changed, 52 insertions(+), 192 deletions(-)
>> >>
>> >LGTM. Thank you for working on this.
>> >
>> >>
>> >> diff --git a/libstdc++-v3/include/bits/chrono_io.h
>> >> b/libstdc++-v3/include/bits/chrono_io.h
>> >> index f8bb485d1..d3740a0e1 100644
>> >> --- a/libstdc++-v3/include/bits/chrono_io.h
>> >> +++ b/libstdc++-v3/include/bits/chrono_io.h
>> >> @@ -884,11 +884,13 @@ namespace __format
>> >> static constexpr const _CharT* _S_minus_empty_spec = _S_chars + 17;
>> >> static constexpr const _CharT* _S_empty_spec = _S_chars + 18;
>> >>
>> >> + public:
>> >> [[__gnu__::__always_inline__]]
>> >> static _Dynamic_format_string<_CharT>
>> >> _S_empty_fs()
>> >> { return _Dynamic_format_string<_CharT>(_S_empty_spec); }
>> >>
>> >> + protected:
>> >> static constexpr const _CharT* _S_weekdays[]
>> >> {
>> >> _GLIBCXX_WIDEN("Sunday"),
>> >> @@ -3607,6 +3609,30 @@ namespace __detail
>> >> }
>> >> }
>> >>
>> >> + // Format into a stack buffer via std::format_to_n with the empty
>> >> + // chrono-spec (_S_empty_fs), then write through __ostream_insert.
>> >> + // The empty spec lets each formatter use its __defSpec, producing
>> >> + // output equivalent to the corresponding operator<<.
>> >> + // _BufSize allows per-type tuning of the stack buffer size.
>> >> + template<size_t _BufSize = 128, typename _CharT, typename _Traits,
>> >>
>> >I am wondering about making buffer size explicit on each call, and
>> >removing the default. But I will handle that before committing, if Jonathan
>> >also like that direction.
>>
>> What would be the advantage of requiring it explicitly every time?
>
> You immediately see what buffer size is expected for each type of chrono
> object,
> and if we remove the default, it will force you to think of one instead of
> defaulting
> to 128.
I don't have any strong opinion on that. 128 characters is not a lot
of stack space to use (anybody formatting wide strings can probably
afford the 512 bytes it uses) so I think the default is OK. But if you
want to change it before pushing, that's fine.
>>
>>
>> >> + typename _Arg, typename... _OptLocale>
>> >> + inline basic_ostream<_CharT, _Traits>&
>> >> + __chrono_write(basic_ostream<_CharT, _Traits>& __os,
>> >> + const _Arg& __arg, const _OptLocale&... __loc)
>> >> + {
>> >> + static_assert(sizeof...(_OptLocale) <= 1);
>> >> + constexpr auto __fs
>> >> + = __format::__formatter_chrono<_CharT>::_S_empty_fs;
>> >>
>> >Nice trick for storing a function pointer. I really like it.
>>
>> We could just make _S_empty_spec public, and then use that instead of
>> _S_empty_fs(), right?
>
> Passing char const*, trigger format_string constructor from that, that will
> perform
> a compile time check for the format string. That will increase compile time
> for no
> good reason.
Oh yes, of course.
>
>>
>>
>> That seems simpler to me.
>>
>> constexpr auto __fs = __format::__formatter_chrono<_CharT>::_S_empty_spec;
>>
>> and then just use __fs instead of __fs()
>
> We could do that if we then use vformat, and
> make_format_args/make_wformat_args,
> to avoid compile-time checks.
We could change std::format to std::vformat, but there's no std:vformat_to_n.
So the patch is OK as-is. Could you push it please?
If you want to remove the =128 default that's OK, your call.
>>
>>
>> >> + constexpr size_t __bufsize = _BufSize;
>> >> + _CharT __buf[__bufsize];
>> >> + auto __res = std::format_to_n(__buf, __bufsize, __loc...,
>> >> + __fs(), __arg);
>> >> + if (static_cast<size_t>(__res.size) <= __bufsize) [[likely]]
>> >> + return std::__ostream_insert(__os, __buf, __res.size);
>> >> + auto __s = std::format(__loc..., __fs(), __arg);
>> >> + return std::__ostream_insert(__os, __s.data(), __s.size());
>> >> + }
>> >> +
>> >> } // namespace __detail
>> >> /// @endcond
>> >>
>> >> @@ -3629,14 +3655,7 @@ namespace __detail
>> >> inline basic_ostream<_CharT, _Traits>&
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os, const day& __d)
>> >> {
>> >> - using _Ctx = __format::__format_context<_CharT>;
>> >> - using _Str = basic_string_view<_CharT>;
>> >> - _Str __s = _GLIBCXX_WIDEN("{:02d} is not a valid day");
>> >> - if (__d.ok())
>> >> - __s = __s.substr(0, 6);
>> >> - auto __u = (unsigned)__d;
>> >> - __os << std::vformat(__s, make_format_args<_Ctx>(__u));
>> >> - return __os;
>> >> + return __detail::__chrono_write<32>(__os, __d);
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits,
>> >> @@ -3657,18 +3676,7 @@ namespace __detail
>> >> inline basic_ostream<_CharT, _Traits>&
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os, const month& __m)
>> >> {
>> >> - using _Ctx = __format::__format_context<_CharT>;
>> >> - using _Str = basic_string_view<_CharT>;
>> >> - _Str __s = _GLIBCXX_WIDEN("{:L%b}{} is not a valid month");
>> >> - if (__m.ok())
>> >> - __os << std::vformat(__os.getloc(), __s.substr(0, 6),
>> >> - make_format_args<_Ctx>(__m));
>> >> - else
>> >> - {
>> >> - auto __u = (unsigned)__m;
>> >> - __os << std::vformat(__s.substr(6),
>> >> make_format_args<_Ctx>(__u));
>> >> - }
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __m, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits,
>> >> @@ -3689,18 +3697,7 @@ namespace __detail
>> >> inline basic_ostream<_CharT, _Traits>&
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os, const year& __y)
>> >> {
>> >> - using _Ctx = __format::__format_context<_CharT>;
>> >> - using _Str = basic_string_view<_CharT>;
>> >> - _Str __s = _GLIBCXX_WIDEN("-{:04d} is not a valid year");
>> >> - if (__y.ok())
>> >> - __s = __s.substr(0, 7);
>> >> - int __i = (int)__y;
>> >> - if (__i >= 0) [[likely]]
>> >> - __s.remove_prefix(1);
>> >> - else
>> >> - __i = -__i;
>> >> - __os << std::vformat(__s, make_format_args<_Ctx>(__i));
>> >> - return __os;
>> >> + return __detail::__chrono_write<32>(__os, __y);
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits,
>> >> @@ -3721,18 +3718,7 @@ namespace __detail
>> >> inline basic_ostream<_CharT, _Traits>&
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os, const weekday& __wd)
>> >> {
>> >> - using _Ctx = __format::__format_context<_CharT>;
>> >> - using _Str = basic_string_view<_CharT>;
>> >> - _Str __s = _GLIBCXX_WIDEN("{:L%a}{} is not a valid weekday");
>> >> - if (__wd.ok())
>> >> - __os << std::vformat(__os.getloc(), __s.substr(0, 6),
>> >> - make_format_args<_Ctx>(__wd));
>> >> - else
>> >> - {
>> >> - auto __c = __wd.c_encoding();
>> >> - __os << std::vformat(__s.substr(6),
>> >> make_format_args<_Ctx>(__c));
>> >> - }
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __wd, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits,
>> >> @@ -3754,23 +3740,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const weekday_indexed& __wdi)
>> >> {
>> >> - // The standard says to format wdi.weekday() and wdi.index() using
>> >> - // either "{:L}[{}]" or "{:L}[{} is not a valid index]". The {:L}
>> >> spec
>> >> - // means to format the weekday using ostringstream, so just do
>> >> that.
>> >> - basic_stringstream<_CharT> __os2;
>> >> - __os2.imbue(__os.getloc());
>> >> - __os2 << __wdi.weekday();
>> >> - const auto __i = __wdi.index();
>> >> - basic_string_view<_CharT> __s
>> >> - = _GLIBCXX_WIDEN("[ is not a valid index]");
>> >> - __os2 << __s[0];
>> >> - __os2 << std::format(_GLIBCXX_WIDEN("{}"), __i);
>> >> - if (__i >= 1 && __i <= 5)
>> >> - __os2 << __s.back();
>> >> - else
>> >> - __os2 << __s.substr(1);
>> >> - __os << __os2.view();
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __wdi, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits>
>> >> @@ -3778,29 +3748,14 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const weekday_last& __wdl)
>> >> {
>> >> - // As above, just write straight to a stringstream, as if by
>> >> "{:L}[last]"
>> >> - basic_stringstream<_CharT> __os2;
>> >> - __os2.imbue(__os.getloc());
>> >> - __os2 << __wdl.weekday() << _GLIBCXX_WIDEN("[last]");
>> >> - __os << __os2.view();
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __wdl, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits>
>> >> inline basic_ostream<_CharT, _Traits>&
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os, const month_day&
>> >> __md)
>> >> {
>> >> - // As above, just write straight to a stringstream, as if by
>> >> "{:L}/{}"
>> >> - basic_stringstream<_CharT> __os2;
>> >> - __os2.imbue(__os.getloc());
>> >> - __os2 << __md.month();
>> >> - if constexpr (is_same_v<_CharT, char>)
>> >> - __os2 << '/';
>> >> - else
>> >> - __os2 << L'/';
>> >> - __os2 << __md.day();
>> >> - __os << __os2.view();
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __md, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits,
>> >> @@ -3824,12 +3779,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const month_day_last& __mdl)
>> >> {
>> >> - // As above, just write straight to a stringstream, as if by
>> >> "{:L}/last"
>> >> - basic_stringstream<_CharT> __os2;
>> >> - __os2.imbue(__os.getloc());
>> >> - __os2 << __mdl.month() << _GLIBCXX_WIDEN("/last");
>> >> - __os << __os2.view();
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __mdl, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits>
>> >> @@ -3837,17 +3787,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const month_weekday& __mwd)
>> >> {
>> >> - // As above, just write straight to a stringstream, as if by
>> >> "{:L}/{:L}"
>> >> - basic_stringstream<_CharT> __os2;
>> >> - __os2.imbue(__os.getloc());
>> >> - __os2 << __mwd.month();
>> >> - if constexpr (is_same_v<_CharT, char>)
>> >> - __os2 << '/';
>> >> - else
>> >> - __os2 << L'/';
>> >> - __os2 << __mwd.weekday_indexed();
>> >> - __os << __os2.view();
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __mwd, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits>
>> >> @@ -3855,34 +3795,14 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const month_weekday_last& __mwdl)
>> >> {
>> >> - // As above, just write straight to a stringstream, as if by
>> >> "{:L}/{:L}"
>> >> - basic_stringstream<_CharT> __os2;
>> >> - __os2.imbue(__os.getloc());
>> >> - __os2 << __mwdl.month();
>> >> - if constexpr (is_same_v<_CharT, char>)
>> >> - __os2 << '/';
>> >> - else
>> >> - __os2 << L'/';
>> >> - __os2 << __mwdl.weekday_last();
>> >> - __os << __os2.view();
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __mwdl, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits>
>> >> inline basic_ostream<_CharT, _Traits>&
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os, const year_month&
>> >> __ym)
>> >> {
>> >> - // As above, just write straight to a stringstream, as if by
>> >> "{}/{:L}"
>> >> - basic_stringstream<_CharT> __os2;
>> >> - __os2.imbue(__os.getloc());
>> >> - __os2 << __ym.year();
>> >> - if constexpr (is_same_v<_CharT, char>)
>> >> - __os2 << '/';
>> >> - else
>> >> - __os2 << L'/';
>> >> - __os2 << __ym.month();
>> >> - __os << __os2.view();
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __ym, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits,
>> >> @@ -3906,12 +3826,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const year_month_day& __ymd)
>> >> {
>> >> - using _Ctx = __format::__format_context<_CharT>;
>> >> - using _Str = basic_string_view<_CharT>;
>> >> - _Str __s = _GLIBCXX_WIDEN("{:%F} is not a valid date");
>> >> - __os << std::vformat(__ymd.ok() ? __s.substr(0, 5) : __s,
>> >> - make_format_args<_Ctx>(__ymd));
>> >> - return __os;
>> >> + return __detail::__chrono_write<64>(__os, __ymd);
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits,
>> >> @@ -3936,17 +3851,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const year_month_day_last& __ymdl)
>> >> {
>> >> - // As above, just write straight to a stringstream, as if by
>> >> "{}/{:L}"
>> >> - basic_stringstream<_CharT> __os2;
>> >> - __os2.imbue(__os.getloc());
>> >> - __os2 << __ymdl.year();
>> >> - if constexpr (is_same_v<_CharT, char>)
>> >> - __os2 << '/';
>> >> - else
>> >> - __os2 << L'/';
>> >> - __os2 << __ymdl.month_day_last();
>> >> - __os << __os2.view();
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __ymdl, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits>
>> >> @@ -3954,19 +3859,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const year_month_weekday& __ymwd)
>> >> {
>> >> - // As above, just write straight to a stringstream, as if by
>> >> - // "{}/{:L}/{:L}"
>> >> - basic_stringstream<_CharT> __os2;
>> >> - __os2.imbue(__os.getloc());
>> >> - _CharT __slash;
>> >> - if constexpr (is_same_v<_CharT, char>)
>> >> - __slash = '/';
>> >> - else
>> >> - __slash = L'/';
>> >> - __os2 << __ymwd.year() << __slash << __ymwd.month() << __slash
>> >> - << __ymwd.weekday_indexed();
>> >> - __os << __os2.view();
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __ymwd, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits>
>> >> @@ -3974,19 +3867,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const year_month_weekday_last& __ymwdl)
>> >> {
>> >> - // As above, just write straight to a stringstream, as if by
>> >> - // "{}/{:L}/{:L}"
>> >> - basic_stringstream<_CharT> __os2;
>> >> - __os2.imbue(__os.getloc());
>> >> - _CharT __slash;
>> >> - if constexpr (is_same_v<_CharT, char>)
>> >> - __slash = '/';
>> >> - else
>> >> - __slash = L'/';
>> >> - __os2 << __ymwdl.year() << __slash << __ymwdl.month() << __slash
>> >> - << __ymwdl.weekday_last();
>> >> - __os << __os2.view();
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __ymwdl, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits, typename _Duration>
>> >> @@ -3994,7 +3875,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const hh_mm_ss<_Duration>& __hms)
>> >> {
>> >> - return __os << format(__os.getloc(), _GLIBCXX_WIDEN("{:L%T}"),
>> >> __hms);
>> >> + return __detail::__chrono_write<64>(__os, __hms, __os.getloc());
>> >> }
>> >>
>> >> #if _GLIBCXX_USE_CXX11_ABI || ! _GLIBCXX_USE_DUAL_ABI
>> >> @@ -4003,7 +3884,7 @@ namespace __detail
>> >> basic_ostream<_CharT, _Traits>&
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os, const sys_info& __i)
>> >> {
>> >> - return __os << std::format(__os.getloc(), _GLIBCXX_WIDEN("{}"),
>> >> __i);
>> >> + return __detail::__chrono_write(__os, __i, __os.getloc());
>> >> }
>> >>
>> >> /// Writes a local_info object to an ostream in an unspecified format.
>> >> @@ -4011,20 +3892,7 @@ namespace __detail
>> >> basic_ostream<_CharT, _Traits>&
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os, const local_info&
>> >> __li)
>> >> {
>> >> - __os << __format::_Separators<_CharT>::_S_squares()[0];
>> >> - if (__li.result == local_info::unique)
>> >> - __os << __li.first;
>> >> - else
>> >> - {
>> >> - if (__li.result == local_info::nonexistent)
>> >> - __os << _GLIBCXX_WIDEN("nonexistent");
>> >> - else
>> >> - __os << _GLIBCXX_WIDEN("ambiguous");
>> >> - __os << _GLIBCXX_WIDEN(" local time between ") << __li.first;
>> >> - __os << _GLIBCXX_WIDEN(" and ") << __li.second;
>> >> - }
>> >> - __os << __format::_Separators<_CharT>::_S_squares()[1];
>> >> - return __os;
>> >> + return __detail::__chrono_write<256>(__os, __li);
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits, typename _Duration,
>> >> @@ -4033,8 +3901,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const zoned_time<_Duration, _TimeZonePtr>& __t)
>> >> {
>> >> - __os << format(__os.getloc(), _GLIBCXX_WIDEN("{:L%F %T %Z}"), __t);
>> >> - return __os;
>> >> + return __detail::__chrono_write(__os, __t, __os.getloc());
>> >> }
>> >> #endif
>> >>
>> >> @@ -4045,16 +3912,14 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const sys_time<_Duration>& __tp)
>> >> {
>> >> - __os << std::format(__os.getloc(), _GLIBCXX_WIDEN("{:L%F %T}"),
>> >> __tp);
>> >> - return __os;
>> >> + return __detail::__chrono_write<64>(__os, __tp, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits>
>> >> inline basic_ostream<_CharT, _Traits>&
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os, const sys_days&
>> >> __dp)
>> >> {
>> >> - __os << year_month_day{__dp};
>> >> - return __os;
>> >> + return __detail::__chrono_write<32>(__os, __dp);
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits, typename _Duration,
>> >> @@ -4090,8 +3955,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const utc_time<_Duration>& __t)
>> >> {
>> >> - __os << std::format(__os.getloc(), _GLIBCXX_WIDEN("{:L%F %T}"),
>> >> __t);
>> >> - return __os;
>> >> + return __detail::__chrono_write<64>(__os, __t, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits, typename _Duration,
>> >> @@ -4125,8 +3989,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const tai_time<_Duration>& __t)
>> >> {
>> >> - __os << std::format(__os.getloc(), _GLIBCXX_WIDEN("{:L%F %T}"),
>> >> __t);
>> >> - return __os;
>> >> + return __detail::__chrono_write<64>(__os, __t, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits, typename _Duration,
>> >> @@ -4164,8 +4027,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const gps_time<_Duration>& __t)
>> >> {
>> >> - __os << std::format(__os.getloc(), _GLIBCXX_WIDEN("{:L%F %T}"),
>> >> __t);
>> >> - return __os;
>> >> + return __detail::__chrono_write<64>(__os, __t, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits, typename _Duration,
>> >> @@ -4202,8 +4064,7 @@ namespace __detail
>> >> operator<<(basic_ostream<_CharT, _Traits>& __os,
>> >> const file_time<_Duration>& __t)
>> >> {
>> >> - __os << std::format(__os.getloc(), _GLIBCXX_WIDEN("{:L%F %T}"),
>> >> __t);
>> >> - return __os;
>> >> + return __detail::__chrono_write<64>(__os, __t, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits, typename _Duration,
>> >> @@ -4228,8 +4089,7 @@ namespace __detail
>> >> // 4257. Stream insertion for chrono::local_time should be
>> >> constrained
>> >> requires requires(const sys_time<_Duration>& __st) { __os << __st; }
>> >> {
>> >> - __os << sys_time<_Duration>{__lt.time_since_epoch()};
>> >> - return __os;
>> >> + return __detail::__chrono_write<64>(__os, __lt, __os.getloc());
>> >> }
>> >>
>> >> template<typename _CharT, typename _Traits, typename _Duration,
>> >> --
>> >> 2.34.1
>> >>
>> >>
>>
