https://gcc.gnu.org/g:bf0465b3e2c3142957444f46b9a3cd3719c8299f
commit r15-11263-gbf0465b3e2c3142957444f46b9a3cd3719c8299f Author: XU Kailiang <[email protected]> Date: Wed Jul 2 15:10:29 2025 +0800 libstdc++: Format chrono %a/%A/%b/%B/%p using locale's time_put [PR117214] C++ formatting locale could have a custom time_put that performs differently from the C locale, so do not use __timepunct directly. This patch for gcc-15 was originally submitted for trunk, but then got rebased and committed as r16-2063-g8ad5968a8dcb47. For the gcc-15 backport we need to go back to the original v1 patch. libstdc++-v3/ChangeLog: PR libstdc++/117214 * include/bits/chrono_io.h (__formatter_chrono::_M_a_A) (__formatter_chrono::_M_b_B, __formatter_chrono::_M_p): Use _M_locale_fmt to format %a/%A/%b/%B/%p. * testsuite/std/time/format/pr117214_custom_timeput.cc: New test. Signed-off-by: XU Kailiang <[email protected]> Reviewed-by: Jonathan Wakely <[email protected]> Diff: --- libstdc++-v3/include/bits/chrono_io.h | 37 +++++++++------------- .../std/time/format/pr117214_custom_timeput.cc | 36 +++++++++++++++++++++ 2 files changed, 51 insertions(+), 22 deletions(-) diff --git a/libstdc++-v3/include/bits/chrono_io.h b/libstdc++-v3/include/bits/chrono_io.h index 243d3ff8026d..d84c6690f01c 100644 --- a/libstdc++-v3/include/bits/chrono_io.h +++ b/libstdc++-v3/include/bits/chrono_io.h @@ -843,14 +843,10 @@ namespace __format __throw_format_error("format error: invalid weekday"); locale __loc = _M_locale(__ctx); - const auto& __tp = use_facet<__timepunct<_CharT>>(__loc); - const _CharT* __days[7]; - if (__full) - __tp._M_days(__days); - else - __tp._M_days_abbreviated(__days); - __string_view __str(__days[__wd.c_encoding()]); - return _M_write(std::move(__out), __loc, __str); + struct tm __tm{}; + __tm.tm_wday = __wd.c_encoding(); + return _M_locale_fmt(std::move(__out), __loc, __tm, + __full ? 'A' : 'a', 0); } template<typename _Tp, typename _FormatContext> @@ -864,14 +860,10 @@ namespace __format if (!__m.ok()) __throw_format_error("format error: invalid month"); locale __loc = _M_locale(__ctx); - const auto& __tp = use_facet<__timepunct<_CharT>>(__loc); - const _CharT* __months[12]; - if (__full) - __tp._M_months(__months); - else - __tp._M_months_abbreviated(__months); - __string_view __str(__months[(unsigned)__m - 1]); - return _M_write(std::move(__out), __loc, __str); + struct tm __tm{}; + __tm.tm_mon = (unsigned)__m - 1; + return _M_locale_fmt(std::move(__out), __loc, __tm, + __full ? 'B' : 'b', 0); } template<typename _Tp, typename _FormatContext> @@ -1196,13 +1188,14 @@ namespace __format _FormatContext& __ctx) const { // %p The locale's equivalent of the AM/PM designations. - auto __hms = _S_hms(__t); + auto __hi = _S_hms(__t).hours().count(); + if (__hi >= 24) [[unlikely]] + __hi %= 24; + locale __loc = _M_locale(__ctx); - const auto& __tp = use_facet<__timepunct<_CharT>>(__loc); - const _CharT* __ampm[2]; - __tp._M_am_pm(__ampm); - return _M_write(std::move(__out), __loc, - __ampm[__hms.hours().count() >= 12]); + struct tm __tm{}; + __tm.tm_hour = __hi; + return _M_locale_fmt(std::move(__out), __loc, __tm, 'p', 0); } template<typename _Tp, typename _FormatContext> diff --git a/libstdc++-v3/testsuite/std/time/format/pr117214_custom_timeput.cc b/libstdc++-v3/testsuite/std/time/format/pr117214_custom_timeput.cc new file mode 100644 index 000000000000..8c9f3d29bc6a --- /dev/null +++ b/libstdc++-v3/testsuite/std/time/format/pr117214_custom_timeput.cc @@ -0,0 +1,36 @@ +// { dg-do run { target c++20 } } + +#include <chrono> +#include <format> +#include <locale> +#include <testsuite_hooks.h> + +struct custom_time_put : 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 + { + using Base = std::time_put<char>; + + switch (format) { + case 'a': case 'A': case 'b': case 'B': case 'p': + *out++ = '['; + *out++ = format; + *out++ = ']'; + } + return Base::do_put(out, io, fill, t, format, modifier); + } +}; + +int main() +{ + using namespace std::chrono; + std::locale loc(std::locale::classic(), new custom_time_put); +#define test(t, fmt, exp) VERIFY( std::format(loc, fmt, t) == exp ) + test(Monday, "{:L%a}", "[a]Mon"); + test(Monday, "{:L%A}", "[A]Monday"); + test(January, "{:L%b}", "[b]Jan"); + test(January, "{:L%B}", "[B]January"); + test(1h, "{:L%p}", "[p]AM"); +}
