On Thu, Jun 26, 2025 at 2:09 PM Jonathan Wakely <[email protected]> wrote:
> On 26/06/25 11:39 +0200, Tomasz Kamiński wrote:
> >This patch extract calls to _M_locale_fmt and construction of the struct
> tm,
> >from the functions dedicated to each specifier, to main format loop in
> >_M_format_to functions. This removes duplicated code repeated for
> specifiers.
>
> Great, this is exactly what I wanted to do. Removing all the branches
> to call _M_locale_fmt from each of the _M_xxx member functions makes
> them smaller and potentially faster.
>
> >To allow _M_locale_fmt to only be called if localized formatting is
> enabled
> >('L' is present in chrono-format-spec), we provide a implementations for
> >locale specific specifiers (%c, %r, %x, %X) that produces the same result
> >as locale::classic():
> > * %c is implemented as separate _M_c method
> > * %r is implemented as separate _M_r method
> > * %x is implemented together with %D, as they provide same behavior,
> > * %X is implemented together with %R as _M_R_X, as both of them do not
> include
> > subseconds.
>
> Nice.
>
> >The handling of subseconds was also extracted to _M_subsecs function that
> is
> >used by _M_S and _M_T specifier. The _M_T is now implemented in terms of
> >_M_R_X (printing time without subseconds) and _M_subs.
> >
> >The __mod responsible for triggering localized formatting was removed from
> >method handling most of specifiers, except:
> > * _M_S (for %S) for which it determines if subseconds should be included,
> > * _M_z (for %z) for which it determines if ':' is used as separator.
> >
> > PR libstdc++/110739
> >
> >libstdc++-v3/ChangeLog:
> >
> > * include/bits/chrono_io.h (__formatter_chrono::_M_use_locale_fmt):
> > Define.
> > (__formatter_chrono::_M_locale_fmt): Moved to front of the class.
> > (__formatter_chrono::_M_format_to): Construct and initialize
> > struct tm and call _M_locale_fmt if needed.
> > (__formatter_chrono::_M_c_r_x_X): Split into separate methods.
> > (__formatter_chrono::_M_c, __formatter_chrono::_M_r): Define.
> > (__formatter_chrono::_M_D): Renamed to _M_D_x.
> > (__formatter_chrono::_M_D_x): Renamed from _M_D.
> > (__formatter_chrono::_M_R_T): Split into _M_R_X and _M_T.
> > (__formatter_chrono::_M_R_X): Extracted from _M_R_T.
> > (__formatter_chrono::_M_T): Define in terms of _M_R_X and
> _M_subsecs.
> > (__formatter_chrono::_M_subsecs): Extracted from _M_S.
> > (__formatter_chrono::_M_S): Replaced __mod with __subs argument,
> > removed _M_locale_fmt call, and delegate to _M_subsecs.
> > (__formatter_chrono::_M_C_y_Y, __formatter_chrono::_M_d_e)
> > (__formatter_chrono::_M_H_I, __formatter_chrono::_M_m)
> > (__formatter_chrono::_M_u_w, __formatter_chrono::_M_U_V_W): Remove
> > __mod argument and call to _M_locale_fmt.
> >---
> > libstdc++-v3/include/bits/chrono_io.h | 340 +++++++++++++-------------
> > 1 file changed, 172 insertions(+), 168 deletions(-)
> >
> >diff --git a/libstdc++-v3/include/bits/chrono_io.h
> b/libstdc++-v3/include/bits/chrono_io.h
> >index 35e95906e6a..d451bde722d 100644
> >--- a/libstdc++-v3/include/bits/chrono_io.h
> >+++ b/libstdc++-v3/include/bits/chrono_io.h
> >@@ -906,6 +906,40 @@ namespace __format
> > return __format::__write(std::move(__out), __s);
> > }
> >
> >+ [[__gnu__::__always_inline__]]
> >+ static bool
> >+ _S_localized_spec(_CharT __conv, _CharT __mod)
> >+ {
> >+ switch (__conv)
> >+ {
> >+ case 'c':
> >+ case 'r':
> >+ case 'x':
> >+ case 'X':
> >+ return true;
> >+ case 'z':
> >+ return false;
> >+ default:
> >+ return (bool)__mod;
> >+ };
> >+ }
> >+
> >+ // Use the formatting locale's std::time_put facet to produce
> >+ // a locale-specific representation.
> >+ template<typename _Iter>
> >+ _Iter
> >+ _M_locale_fmt(_Iter __out, const locale& __loc, const struct tm&
> __tm,
> >+ 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)
> >+ __out = _M_write(std::move(__out), __loc, __os.view());
> >+ return __out;
> >+ }
> >+
> > template<typename _Out, typename _FormatContext>
> > _Out
> > _M_format_to(const _ChronoData<_CharT>& __t, _Out __out,
> >@@ -923,6 +957,36 @@ namespace __format
> > return std::move(__out);
> > };
> >
> >+ struct tm __tm{};
> >+ bool __use_locale_fmt = false;
> >+ if (_M_spec._M_localized && _M_spec._M_locale_specific)
> >+ if (__fc.locale() != locale::classic())
> >+ {
> >+ __use_locale_fmt = true;
> >+
> >+ __tm.tm_year = (int)__t._M_year - 1900;
> >+ __tm.tm_yday = __t._M_day_of_year.count();
> >+ __tm.tm_mon = (unsigned)__t._M_month - 1;
> >+ __tm.tm_mday = (unsigned)__t._M_day;
> >+ __tm.tm_wday = __t._M_weekday.c_encoding();
> >+ __tm.tm_hour = __t._M_hours.count();
> >+ __tm.tm_min = __t._M_minutes.count();
> >+ __tm.tm_sec = __t._M_seconds.count();
> >+
> >+ // Some locales use %Z in their %c format but we don't
> want strftime
> >+ // to use the system's local time zone (from
> /etc/localtime or $TZ)
> >+ // as the output for %Z. Setting tm_isdst to -1 says there
> is no
> >+ // time zone info available for the time in __tm.
> >+ __tm.tm_isdst = -1;
> >+
> >+#ifdef _GLIBCXX_USE_STRUCT_TM_TM_ZONE
> >+ // POSIX.1-2024 adds tm.tm_zone which will be used for %Z.
> >+ // BSD has had tm_zone since 1987 but as char* so cast
> away const.
> >+ if (__t._M_zone_cstr)
> >+ __tm.tm_zone = const_cast<char*>(__t._M_zone_cstr);
> >+#endif
> >+ }
> >+
> > // Characters to output for "%n", "%t" and "%%" specifiers.
> > constexpr const _CharT* __literals = _GLIBCXX_WIDEN("\n\t%");
> >
> >@@ -932,7 +996,10 @@ namespace __format
> > do
> > {
> > _CharT __c = *__first++;
> >- switch (__c)
> >+ if (__use_locale_fmt && _S_localized_spec(__c, __mod))
> [[unlikely]]
> >+ __out = _M_locale_fmt(std::move(__out), __fc.locale(),
> >+ __tm, __c, __mod);
> >+ else switch (__c)
> > {
> > // %\0 is extension for handling weekday index
> > case '\0':
> >@@ -948,22 +1015,20 @@ namespace __format
> > __out = _M_b_B(__t._M_month, std::move(__out), __fc, __c
> == 'B');
> > break;
> > case 'c':
> >- case 'r':
> >- case 'x':
> >- case 'X':
> >- __out = _M_c_r_x_X(__t, std::move(__out), __fc, __c,
> __mod);
> >+ __out = _M_c(__t, std::move(__out), __fc);
> > break;
> > case 'C':
> > case 'y':
> > case 'Y':
> >- __out = _M_C_y_Y(__t._M_year, std::move(__out), __fc,
> __c, __mod);
> >+ __out = _M_C_y_Y(__t._M_year, std::move(__out), __fc,
> __c);
> > break;
> > case 'd':
> > case 'e':
> >- __out = _M_d_e(__t._M_day, std::move(__out), __fc, __c,
> __mod == 'O');
> >+ __out = _M_d_e(__t._M_day, std::move(__out), __fc, __c);
> > break;
> > case 'D':
> >- __out = _M_D(__t, std::move(__out), __fc);
> >+ case 'x':
> >+ __out = _M_D_x(__t, std::move(__out), __fc);
> > break;
> > case 'F':
> > __out = _M_F(__t, std::move(__out), __fc);
> >@@ -974,16 +1039,16 @@ namespace __format
> > break;
> > case 'H':
> > case 'I':
> >- __out = _M_H_I(__t._M_hours, __print_sign(), __fc, __c,
> __mod == 'O');
> >+ __out = _M_H_I(__t._M_hours, __print_sign(), __fc, __c);
> > break;
> > case 'j':
> > __out = _M_j(__t, __print_sign(), __fc);
> > break;
> > case 'm':
> >- __out = _M_m(__t._M_month, std::move(__out), __fc, __mod
> == 'O');
> >+ __out = _M_m(__t._M_month, std::move(__out), __fc);
> > break;
> > case 'M':
> >- __out = _M_M(__t._M_minutes, __print_sign(), __fc, __mod
> == 'O');
> >+ __out = _M_M(__t._M_minutes, __print_sign(), __fc);
> > break;
> > case 'p':
> > __out = _M_p(__t._M_hours, std::move(__out), __fc);
> >@@ -994,22 +1059,28 @@ namespace __format
> > case 'Q':
> > __out = _M_Q(__t, __print_sign(), __fc);
> > break;
> >+ case 'r':
> >+ __out = _M_r(__t, __print_sign(), __fc);
> >+ break;
> > case 'R':
> >+ case 'X':
> >+ __out = _M_R_X(__t, __print_sign(), __fc, __c != 'R');
> >+ break;
> > case 'T':
> >- __out = _M_R_T(__t, __print_sign(), __fc, __c == 'T');
> >+ __out = _M_T(__t, __print_sign(), __fc);
> > break;
> >+
> > case 'S':
> >- __out = _M_S(__t, __print_sign(), __fc, __mod == 'O');
> >+ __out = _M_S(__t, __print_sign(), __fc, __mod != 'O');
> > break;
> > case 'u':
> > case 'w':
> >- __out = _M_u_w(__t._M_weekday, std::move(__out), __fc,
> __c, __mod == 'O');
> >+ __out = _M_u_w(__t._M_weekday, std::move(__out), __fc,
> __c);
> > break;
> > case 'U':
> > case 'V':
> > case 'W':
> >- __out = _M_U_V_W(__t, std::move(__out), __fc, __c,
> >- __mod == 'O');
> >+ __out = _M_U_V_W(__t, std::move(__out), __fc, __c);
> > break;
> > case 'z':
> > __out = _M_z(__t._M_zone_offset, std::move(__out), __fc,
> (bool)__mod);
> >@@ -1132,50 +1203,27 @@ namespace __format
> >
> > template<typename _FormatContext>
> > typename _FormatContext::iterator
> >- _M_c_r_x_X(const _ChronoData<_CharT>& __t, typename
> _FormatContext::iterator __out,
> >- _FormatContext& __ctx, _CharT __conv, _CharT __mod)
> const
> >+ _M_c(const _ChronoData<_CharT>& __t, typename
> _FormatContext::iterator __out,
> >+ _FormatContext& __ctx) const
> > {
> >- // %c Locale's date and time representation.
> >- // %Ec Locale's alternate date and time representation.
> >- // %r Locale's 12-hour clock time.
> >- // %x Locale's date rep
> >- // %Ex Locale's alternative date representation.
> >- // %X Locale's time rep
> >- // %EX Locale's alternative time representation.
> >-
> >- using namespace chrono;
> >- struct tm __tm{};
> >-
> >- // Some locales use %Z in their %c format but we don't want
> strftime
> >- // to use the system's local time zone (from /etc/localtime or
> $TZ)
> >- // as the output for %Z. Setting tm_isdst to -1 says there is no
> >- // time zone info available for the time in __tm.
> >- __tm.tm_isdst = -1;
> >-
> >-#ifdef _GLIBCXX_USE_STRUCT_TM_TM_ZONE
> >- // POSIX.1-2024 adds tm.tm_zone which will be used for %Z.
> >- // BSD has had tm_zone since 1987 but as char* so cast away
> const.
> >- if (__t._M_zone_cstr)
> >- __tm.tm_zone = const_cast<char*>(__t._M_zone_cstr);
> >-#endif
> >-
> >- __tm.tm_year = (int)__t._M_year - 1900;
> >- __tm.tm_yday = __t._M_day_of_year.count();
> >- __tm.tm_mon = (unsigned)__t._M_month - 1;
> >- __tm.tm_mday = (unsigned)__t._M_day;
> >- __tm.tm_wday = __t._M_weekday.c_encoding();
> >- __tm.tm_hour = __t._M_hours.count();
> >- __tm.tm_min = __t._M_minutes.count();
> >- __tm.tm_sec = __t._M_seconds.count();
> >-
> >- return _M_locale_fmt(std::move(__out), _M_locale(__ctx), __tm,
> >- __conv, __mod);
> >+ // %c Locale's date and time representation, for C-locale: %a
> %b %e %T %Y
> >+ // %Ec Locale's alternate date and time representation, for
> C-locale same as above
> >+
> >+ __out = _M_a_A(__t._M_weekday, std::move(__out), __ctx, false);
> >+ *__out = _S_space;
> >+ __out = _M_b_B(__t._M_month, std::move(++__out), __ctx, false);
> >+ *__out = _S_space;
> >+ __out = _M_d_e(__t._M_day, std::move(++__out), __ctx, 'e');
> >+ *__out = _S_space;
> >+ __out = _M_R_X(__t, std::move(++__out), __ctx, true);
> >+ *__out = _S_space;
> >+ return _M_C_y_Y(__t._M_year, std::move(__out), __ctx, 'Y');
> > }
> >
> > template<typename _FormatContext>
> > typename _FormatContext::iterator
> > _M_C_y_Y(chrono::year __y, typename _FormatContext::iterator __out,
> >- _FormatContext& __ctx, _CharT __conv, _CharT __mod = 0)
> const
> >+ _FormatContext& __ctx, _CharT __conv) const
> > {
> > // %C Year divided by 100 using floored division.
> > // %EC Locale's alternative preresentation of the century (era
> name).
> >@@ -1185,15 +1233,6 @@ namespace __format
> > // %Y Year as a decimal number.
> > // %EY Locale's alternative full year representation.
> >
> >- if (__mod && _M_spec._M_localized) [[unlikely]]
> >- if (auto __loc = __ctx.locale(); __loc != locale::classic())
> >- {
> >- struct tm __tm{};
> >- __tm.tm_year = (int)__y - 1900;
> >- return _M_locale_fmt(std::move(__out), __loc, __tm,
> >- __conv, __mod);
> >- }
> >-
> > int __yi = (int)__y;
> > const bool __is_neg = __yi < 0;
> > __yi = __builtin_abs(__yi);
> >@@ -1235,9 +1274,13 @@ namespace __format
> >
> > template<typename _FormatContext>
> > typename _FormatContext::iterator
> >- _M_D(const _ChronoData<_CharT>& __t, typename
> _FormatContext::iterator __out,
> >- _FormatContext&) const
> >+ _M_D_x(const _ChronoData<_CharT>& __t, typename
> _FormatContext::iterator __out,
> >+ _FormatContext&) const
> > {
> >+ // %D Equivalent to %m/%d/%y
> >+ // %x Locale's date rep, for C-locale: %m/%d/%y
> >+ // %Ex Locale's alternative date representation, for C-locale
> same as above
> >+
> > auto __di = (unsigned)__t._M_day;
> > auto __mi = (unsigned)__t._M_month;
> > auto __yi = __builtin_abs((int)__t._M_year) % 100;
> >@@ -1267,7 +1310,7 @@ namespace __format
> > template<typename _FormatContext>
> > typename _FormatContext::iterator
> > _M_d_e(chrono::day __d, typename _FormatContext::iterator __out,
> >- _FormatContext& __ctx, _CharT __conv, bool __mod = false)
> const
> >+ _FormatContext& __ctx, _CharT __conv) const
> > {
> > // %d The day of month as a decimal number.
> > // %Od Locale's alternative representation.
> >@@ -1276,15 +1319,6 @@ namespace __format
> >
> > unsigned __i = (unsigned)__d;
> >
> >- if (__mod && _M_spec._M_localized) [[unlikely]]
> >- if (auto __loc = __ctx.locale(); __loc != locale::classic())
> >- {
> >- struct tm __tm{};
> >- __tm.tm_mday = __i;
> >- return _M_locale_fmt(std::move(__out), __loc, __tm,
> >- (char)__conv, 'O');
> >- }
> >-
> > _CharT __buf[3];
> > auto __sv = _S_str_d2(__buf, __i);
> > if (__conv == _CharT('e') && __i < 10)
> >@@ -1360,7 +1394,7 @@ namespace __format
> > template<typename _FormatContext>
> > typename _FormatContext::iterator
> > _M_H_I(chrono::hours __h, typename _FormatContext::iterator __out,
> >- _FormatContext& __ctx, _CharT __conv, bool __mod = false)
> const
> >+ _FormatContext& __ctx, _CharT __conv) const
> > {
> > // %H The hour (24-hour clock) as a decimal number.
> > // %OH Locale's alternative representation.
> >@@ -1369,15 +1403,6 @@ namespace __format
> >
> > int __i = __h.count();
> >
> >- if (__mod && _M_spec._M_localized) [[unlikely]]
> >- if (auto __loc = __ctx.locale(); __loc != locale::classic())
> >- {
> >- struct tm __tm{};
> >- __tm.tm_hour = __i;
> >- return _M_locale_fmt(std::move(__out), __loc, __tm,
> >- (char)__conv, 'O');
> >- }
> >-
> > if (__conv == _CharT('I'))
> > {
> > __i %= 12;
> >@@ -1409,22 +1434,13 @@ namespace __format
> > template<typename _FormatContext>
> > typename _FormatContext::iterator
> > _M_m(chrono::month __m, typename _FormatContext::iterator __out,
> >- _FormatContext& __ctx, bool __mod) const
> >+ _FormatContext& __ctx) const
> > {
> > // %m month as a decimal number.
> > // %Om Locale's alternative representation.
> >
> > auto __i = (unsigned)__m;
> >
> >- if (__mod && _M_spec._M_localized) [[unlikely]] // %Om
> >- if (auto __loc = __ctx.locale(); __loc != locale::classic())
> >- {
> >- struct tm __tm{};
> >- __tm.tm_mon = __i - 1;
> >- return _M_locale_fmt(std::move(__out), __loc, __tm,
> >- 'm', 'O');
> >- }
> >-
> > _CharT __buf[3];
> > return __format::__write(std::move(__out), _S_str_d2(__buf,
> __i));
> > }
> >@@ -1432,22 +1448,12 @@ namespace __format
> > template<typename _FormatContext>
> > typename _FormatContext::iterator
> > _M_M(chrono::minutes __m, typename _FormatContext::iterator __out,
> >- _FormatContext& __ctx, bool __mod) const
> >+ _FormatContext& __ctx) const
> > {
> > // %M The minute as a decimal number.
> > // %OM Locale's alternative representation.
> >
> > auto __i = __m.count();
> >-
> >- if (__mod && _M_spec._M_localized) [[unlikely]] // %OM
> >- if (auto __loc = __ctx.locale(); __loc != locale::classic())
> >- {
> >- struct tm __tm{};
> >- __tm.tm_min = __i;
> >- return _M_locale_fmt(std::move(__out), __loc, __tm,
> >- 'M', 'O');
> >- }
> >-
> > return __format::__write(std::move(__out), _S_two_digits(__i));
> > }
> >
> >@@ -1488,17 +1494,42 @@ namespace __format
> >
> > template<typename _FormatContext>
> > typename _FormatContext::iterator
> >- _M_R_T(const _ChronoData<_CharT>& __t, typename
> _FormatContext::iterator __out,
> >+ _M_r(const _ChronoData<_CharT>& __t, typename
> _FormatContext::iterator __out,
> >+ _FormatContext& __ctx) const
> >+ {
> >+ // %r Locale's 12-hour clock time, for C-locale: %I:%M:%S %p
> >+ auto __hi = __t._M_hours.count() % 12;
> >+ if (__hi == 0)
> >+ __hi = 12;
> >+
> >+ _CharT __buf[9];
> >+ __buf[2] = _S_colon;
> >+ __buf[5] = _S_colon;
> >+ __buf[8] = _S_space;
> >+ _S_fill_two_digits(__buf, __hi);
> >+ _S_fill_two_digits(__buf + 3, __t._M_minutes.count());
> >+ _S_fill_two_digits(__buf + 6, __t._M_seconds.count());
> >+
> >+ __string_view __sv(__buf, 9);
> >+ __out = __format::__write(std::move(__out), __sv);
> >+ return _M_p(__t._M_hours, std::move(__out), __ctx);
> >+ }
> >+
> >+ template<typename _FormatContext>
> >+ typename _FormatContext::iterator
> >+ _M_R_X(const _ChronoData<_CharT>& __t, typename
> _FormatContext::iterator __out,
> > _FormatContext& __ctx, bool __secs) const
> > {
> >- // %R Equivalent to %H:%M
> >- // %T Equivalent to %H:%M:%S
> >+ // %R Equivalent to %H:%M
> >+ // %X Locale's time rep, for C-locale: %H:%M:%S (without
> subseconds)
> >+ // %EX Locale's alternative time representation, for C-locale
> same as above
> >+
> > auto __hi = __t._M_hours.count();
> >
> >- _CharT __buf[6];
> >+ _CharT __buf[8];
> > __buf[2] = _S_colon;
> > __buf[5] = _S_colon;
> >- __string_view __sv(__buf, 5 + __secs);
> >+ __string_view __sv(__buf, 8);
> >
> > if (__hi >= 100) [[unlikely]]
> > {
> >@@ -1509,39 +1540,39 @@ namespace __format
> > _S_fill_two_digits(__buf, __hi);
> >
> > _S_fill_two_digits(__buf + 3, __t._M_minutes.count());
> >- __out = __format::__write(std::move(__out), __sv);
> > if (__secs)
> >- __out = _M_S(__t, std::move(__out), __ctx);
> >- return __out;
> >+ _S_fill_two_digits(__buf + 6, __t._M_seconds.count());
> >+ else
> >+ __sv.remove_suffix(3);
> >+
> >+ return __format::__write(std::move(__out), __sv);
> > }
> >
> > template<typename _FormatContext>
> > typename _FormatContext::iterator
> > _M_S(const _ChronoData<_CharT>& __t, typename
> _FormatContext::iterator __out,
> >- _FormatContext& __ctx, bool __mod = false) const
> >+ _FormatContext& __ctx, bool __subs = true) const
> > {
> >- // %S Seconds as a decimal number.
>
> Doesn't this function still handle %S formats? Should this comment be kept?
>
Yes, it gets called to handle '%S' in the big switch. It is no longer
called by _M_T, which calls _M_subsecs
directly.
>
> Apart from that, this patch looks great - OK for trunk (after the
> _ChronoData one, obviously).
>
>
> > // %OS The locale's alternative representation.
> > auto __s = __t._M_seconds;
> >
> >- if (__mod && _M_spec._M_localized) [[unlikely]] // %OS
> >- if (auto __loc = __ctx.locale(); __loc != locale::classic())
> >- {
> >- struct tm __tm{};
> >- __tm.tm_sec = (int)__s.count();
> >- return _M_locale_fmt(std::move(__out), __loc, __tm,
> >- 'S', 'O');
> >- }
> >-
> > __out = __format::__write(std::move(__out),
> >- _S_two_digits(__s.count()));
> >+ _S_two_digits(__s.count()));
> >+ if (__subs)
> >+ __out = _M_subsecs(__t, std::move(__out), __ctx);
> >+ return __out;
> >+ }
> >
> >+ template<typename _FormatContext>
> >+ typename _FormatContext::iterator
> >+ _M_subsecs(const _ChronoData<_CharT>& __t,
> >+ typename _FormatContext::iterator __out,
> >+ _FormatContext& __ctx) const
> >+ {
> > unsigned __prec = _M_spec._M_prec_kind != _WP_none
> > ? _M_spec._M_get_precision(__ctx)
> > : _M_spec._M_prec;
> >-
> >- // %OS formats don't include subseconds
> >- if (__prec == 0 || __mod)
> >+ if (__prec == 0)
> > return __out;
> >
> > _CharT __dot = _S_dot;
> >@@ -1595,25 +1626,25 @@ namespace __format
> >
> > // %t handled in _M_format
> >
> >+ template<typename _FormatContext>
> >+ typename _FormatContext::iterator
> >+ _M_T(const _ChronoData<_CharT>& __t, typename
> _FormatContext::iterator __out,
> >+ _FormatContext& __ctx) const
> >+ {
> >+ // %T Equivalent to %H:%M:%S, with subseconds
> >+ __out = _M_R_X(__t, std::move(__out), __ctx, true);
> >+ return _M_subsecs(__t, std::move(__out), __ctx);
> >+ }
> >+
> > template<typename _FormatContext>
> > typename _FormatContext::iterator
> > _M_u_w(chrono::weekday __wd, typename _FormatContext::iterator
> __out,
> >- _FormatContext& __ctx, _CharT __conv, bool __mod = false)
> const
> >+ _FormatContext& __ctx, _CharT __conv) const
> > {
> > // %u ISO weekday as a decimal number (1-7), where Monday is 1.
> > // %Ou Locale's alternative numeric rep.
> > // %w Weekday as a decimal number (0-6), where Sunday is 0.
> > // %Ow Locale's alternative numeric rep.
> >-
> >- if (__mod && _M_spec._M_localized) [[unlikely]]
> >- if (auto __loc = __ctx.locale(); __loc != locale::classic())
> >- {
> >- struct tm __tm{};
> >- __tm.tm_wday = __wd.c_encoding();
> >- return _M_locale_fmt(std::move(__out), __loc, __tm,
> >- (char)__conv, 'O');
> >- }
> >-
> > unsigned __wdi = __conv == 'u' ? __wd.iso_encoding()
> > : __wd.c_encoding();
> > _CharT __buf[3];
> >@@ -1623,7 +1654,7 @@ namespace __format
> > template<typename _FormatContext>
> > typename _FormatContext::iterator
> > _M_U_V_W(const _ChronoData<_CharT>& __t, typename
> _FormatContext::iterator __out,
> >- _FormatContext& __ctx, _CharT __conv, bool __mod = false)
> const
> >+ _FormatContext& __ctx, _CharT __conv) const
> > {
> > // %U Week number of the year as a decimal number, from first
> Sunday.
> > // %OU Locale's alternative numeric rep.
> >@@ -1633,17 +1664,6 @@ namespace __format
> > // %OW Locale's alternative numeric rep.
> > using namespace chrono;
> >
> >- if (__mod && _M_spec._M_localized) [[unlikely]]
> >- if (auto __loc = __ctx.locale(); __loc != locale::classic())
> >- {
> >- struct tm __tm{};
> >- __tm.tm_year = (int)__t._M_year - 1900;
> >- __tm.tm_yday = __t._M_day_of_year.count();
> >- __tm.tm_wday = __t._M_weekday.c_encoding();
> >- return _M_locale_fmt(std::move(__out), __loc, __tm,
> >- (char)__conv, 'O');
> >- }
> >-
> > auto __d = __t._M_ldays;
> > local_days __first; // First day of week 1.
> > if (__conv == 'V') // W01 begins on Monday before first Thursday.
> >@@ -1755,22 +1775,6 @@ namespace __format
> > __buf[2] = _S_chars[__n % 10];
> > return __string_view(__buf.data(), 3);
> > }
> >-
> >- // Use the formatting locale's std::time_put facet to produce
> >- // a locale-specific representation.
> >- template<typename _Iter>
> >- _Iter
> >- _M_locale_fmt(_Iter __out, const locale& __loc, const struct tm&
> __tm,
> >- 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)
> >- __out = _M_write(std::move(__out), __loc, __os.view());
> >- return __out;
> >- }
> > };
> >
> > template<typename _CharT>
> >--
> >2.49.0
> >
> >
>
>
