[NFC][chrono][test] Fixes some tests on Windows.

[Mordante]

Summary

This updates the tests to match the actual output on Windows.
Note some tests still need more investigation.

[ldionne]

Nice, thanks!

libcxx/test/std/time/time.syn/formatter.hh_mm_ss.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
 
-// TODO FMT Investigate Windows issues.
-// UNSUPPORTED: msvc, target={{.+}}-windows-gnu
-
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
 // XFAIL: availability-fp_to_chars-missing
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
 // <chrono>

 #endif
            "%X='01:01:01'\t"
            "%EX='01:01:01'\t"
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(std::chrono::duration<double>(3661.123456)));
 
   // Use supplied locale (ja_JP). This locale has a different alternate.
-#if defined(__APPLE__) || defined(_AIX)
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("%H='00'\t"
            "%OH='00'\t"
            "%I='12'\t"
            "%OI='12'\t"
            "%M='00'\t"
            "%OM='00'\t"
            "%S='00'\t"
            "%OS='00'\t"
 #  if defined(__APPLE__)
            "%p='AM'\t"
 #  else
            "%p='午前'\t"
 #  endif
            "%R='00:00'\t"
            "%T='00:00:00'\t"
 #  if defined(__APPLE__)
            "%r='12:00:00 AM'\t"
            "%X='00時00分00秒'\t"
            "%EX='00時00分00秒'\t"
+#  elif defined(_WIN32)
+           "%r='0:00:00'\t"
+           "%X='0:00:00'\t"
+           "%EX='0:00:00'\t"
 #  else
            "%r='午前12:00:00'\t"
            "%X='00:00:00'\t"
            "%EX='00:00:00'\t"
 #  endif
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(0s));
#  else
            "%p='午後'\t"
 #  endif
            "%R='23:31'\t"
            "%T='23:31:30.123'\t"
 #  if defined(__APPLE__)
            "%r='11:31:30 PM'\t"
            "%X='23時31分30秒'\t"
            "%EX='23時31分30秒'\t"
+#  elif defined(_WIN32)
+           "%r='23:31:30'\t"
+           "%X='23:31:30'\t"
+           "%EX='23:31:30'\t"
 #  else
            "%r='午後11:31:30'\t"
            "%X='23:31:30'\t"
            "%EX='23:31:30'\t"
 #  endif
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(23h + 31min + 30s + 123ms));
#  else
            "%p='午前'\t"
 #  endif
            "%R='03:02'\t"
            "%T='03:02:01.123456789012'\t"
 #  if defined(__APPLE__)
            "%r='03:02:01 AM'\t"
            "%X='03時02分01秒'\t"
            "%EX='03時02分01秒'\t"
+#  elif defined(_WIN32)
+           "%r='3:02:01'\t"
+           "%X='3:02:01'\t"
+           "%EX='3:02:01'\t"
 #  else
            "%r='午前03:02:01'\t"
            "%X='03:02:01'\t"
            "%EX='03:02:01'\t"
 #  endif
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(-(3h + 2min + 1s + std::chrono::duration<std::int64_t, std::pico>(123456789012))));
#  else
            "%p='午前'\t"
 #  endif
            "%R='01:01'\t"
            "%T='01:01:01'\t"
 #  if defined(__APPLE__)
            "%r='01:01:01 AM'\t"
            "%X='01時01分01秒'\t"
            "%EX='01時01分01秒'\t"
+#  elif defined(_WIN32)
+           "%r='1:01:01'\t"
+           "%X='1:01:01'\t"
+           "%EX='1:01:01'\t"
 #  else
            "%r='午前01:01:01'\t"
            "%X='01:01:01'\t"
            "%EX='01:01:01'\t"
 #  endif
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(std::chrono::duration<double>(3661.123456)));
-#else  // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("%H='00'\t"
            "%OH='〇'\t"
            "%I='12'\t"
            "%OI='十二'\t"
            "%M='00'\t"
            "%OM='〇'\t"
            "%S='00'\t"
check(loc,
            "%R='01:01'\t"
            "%T='01:01:01'\t"
            "%r='午前01時01分01秒'\t"
            "%X='01時01分01秒'\t"
            "%EX='01時01分01秒'\t"
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(std::chrono::duration<double>(3661.123456)));
-#endif // defined(__APPLE__) || defined(_AIX)
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
 
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_invalid_values() {
   using namespace std::literals::chrono_literals;
 

libcxx/test/std/time/time.syn/formatter.day.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
 
-// TODO FMT Investigate Windows issues.
-// UNSUPPORTED: msvc, target={{.+}}-windows-gnu
-
 // TODO FMT This test should not require std::to_chars(floating-point)
 // XFAIL: availability-fp_to_chars-missing
 
+// TODO FMT Investigate Windows issues.
+// XFAIL: msvc
+
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
 // <chrono>
 
 // template<class charT> struct formatter<chrono::day, charT>;
 
 #include <chrono>
static void test_valid_values() {
 
   constexpr std::basic_string_view<CharT> fmt  = SV("{:%%d='%d'%t%%Od='%Od'%t%%e='%e'%t%%Oe='%Oe'%n}");
   constexpr std::basic_string_view<CharT> lfmt = SV("{:L%%d='%d'%t%%Od='%Od'%t%%e='%e'%t%%Oe='%Oe'%n}");
 
   const std::locale loc(LOCALE_ja_JP_UTF_8);
   std::locale::global(std::locale(LOCALE_fr_FR_UTF_8));
 
   // Non localized output using C-locale
+#if defined(_WIN32)
+  check(SV("%d=''\t%Od=''\t%e=''\t%Oe=''\n"), fmt, 0d);
+#else
   check(SV("%d='00'\t%Od='00'\t%e=' 0'\t%Oe=' 0'\n"), fmt, 0d);
+#endif
   check(SV("%d='01'\t%Od='01'\t%e=' 1'\t%Oe=' 1'\n"), fmt, 1d);
   check(SV("%d='31'\t%Od='31'\t%e='31'\t%Oe='31'\n"), fmt, 31d);
-#if defined(_AIX)
+#if defined(_WIN32)
+  check(SV("%d=''\t%Od=''\t%e=''\t%Oe=''\n"), fmt, 0d);
+#elif defined(_AIX)
   check(SV("%d='55'\t%Od='55'\t%e='55'\t%Oe='55'\n"), fmt, 255d);
 #else
   check(SV("%d='255'\t%Od='255'\t%e='255'\t%Oe='255'\n"), fmt, 255d);
 #endif
 
   // Use the global locale (fr_FR)
+#if defined(_WIN32)
+  check(SV("%d=''\t%Od=''\t%e=''\t%Oe=''\n"), lfmt, 0d);
+#else
   check(SV("%d='00'\t%Od='00'\t%e=' 0'\t%Oe=' 0'\n"), lfmt, 0d);
+#endif
   check(SV("%d='01'\t%Od='01'\t%e=' 1'\t%Oe=' 1'\n"), lfmt, 1d);
   check(SV("%d='31'\t%Od='31'\t%e='31'\t%Oe='31'\n"), lfmt, 31d);
-#if defined(_AIX)
+#if defined(_WIN32)
+  check(SV("%d=''\t%Od=''\t%e=''\t%Oe=''\n"), lfmt, 255d);
+#elif defined(_AIX)
   check(SV("%d='55'\t%Od='55'\t%e='55'\t%Oe='55'\n"), lfmt, 255d);
 #else
   check(SV("%d='255'\t%Od='255'\t%e='255'\t%Oe='255'\n"), lfmt, 255d);
 #endif
 
   // Use supplied locale (ja_JP). This locale has a different alternate on some platforms.
-#if defined(__APPLE__) || defined(_AIX)
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
+#  if defined(_WIN32)
+  check(loc, SV("%d=''\t%Od=''\t%e=''\t%Oe=''\n"), lfmt, 0d);
+#  else
   check(loc, SV("%d='00'\t%Od='00'\t%e=' 0'\t%Oe=' 0'\n"), lfmt, 0d);
+#  endif
   check(loc, SV("%d='01'\t%Od='01'\t%e=' 1'\t%Oe=' 1'\n"), lfmt, 1d);
   check(loc, SV("%d='31'\t%Od='31'\t%e='31'\t%Oe='31'\n"), lfmt, 31d);
-#  if defined(_AIX)
+#  if defined(_WIN32)
+  check(SV("%d=''\t%Od=''\t%e=''\t%Oe=''\n"), fmt, 255d);
+#  elif defined(_AIX)
   check(SV("%d='55'\t%Od='55'\t%e='55'\t%Oe='55'\n"), fmt, 255d);
 #  else
   check(SV("%d='255'\t%Od='255'\t%e='255'\t%Oe='255'\n"), fmt, 255d);
 #  endif
-#else  // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc, SV("%d='00'\t%Od='〇'\t%e=' 0'\t%Oe='〇'\n"), lfmt, 0d);
   check(loc, SV("%d='01'\t%Od='一'\t%e=' 1'\t%Oe='一'\n"), lfmt, 1d);
   check(loc, SV("%d='31'\t%Od='三十一'\t%e='31'\t%Oe='三十一'\n"), lfmt, 31d);
   check(loc, SV("%d='255'\t%Od='255'\t%e='255'\t%Oe='255'\n"), lfmt, 255d);
-#endif // defined(__APPLE__) || defined(_AIX)
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
 
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test() {
   using namespace std::literals::chrono_literals;
 

libcxx/test/std/time/time.syn/formatter.duration.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
 
-// TODO FMT Investigate Windows issues.
-// UNSUPPORTED: msvc, target={{.+}}-windows-gnu
-
 // XFAIL: availability-fp_to_chars-missing
 
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
 // <chrono>
 
 //  template<class Rep, class Period, class charT>

 #if defined(_AIX)
            "%p='AM'\t"
 #else
            "%p=''\t"
 #endif
            "%R='00:00'\t"
            "%T='00:00:00'\t"
 #ifdef _WIN32
-           "%r='12:00:00'\t"
+           "%r='00:00:00'\t"
 #elif defined(_AIX)
            "%r='12:00:00 AM'\t"
 #elif defined(__APPLE__)
            "%r=''\t"
 #else
            "%r='12:00:00 '\t"
 #endif
            "%X='00:00:00'\t"

 #if defined(_AIX)
            "%p='PM'\t"
 #else
            "%p=''\t"
 #endif
            "%R='12:00'\t"
            "%T='12:00:00'\t"
 #ifdef _WIN32
-           "%r='00:00:00'\t"
+           "%r='12:00:00'\t"
 #elif defined(_AIX)
            "%r='12:00:00 PM'\t"
 #elif defined(__APPLE__)
            "%r=''\t"
 #else
            "%r='12:00:00 '\t"
 #endif
            "%X='12:00:00'\t"
#else
            "%p=''\t"
 #endif
            "%R='23:59'\t"
            "%T='23:59:59'\t"
 #if defined(_AIX)
            "%r='11:59:59 PM'\t"
 #elif defined(__APPLE__)
            "%r=''\t"
+#elif defined(_WIN32)
+           "%r='23:59:59'\t"
 #else
            "%r='11:59:59 '\t"
 #endif
            "%X='23:59:59'\t"
            "%EX='23:59:59'\t"
            "%j='0'\t"
            "%Q='86399'\t"
            "%q='s'\t"

 #if defined(_AIX)
            "%p='AM'\t"
 #else
            "%p=''\t"
 #endif
            "%R='00:00'\t"
            "%T='00:00:00'\t"
 #ifdef _WIN32
-           "%r='12:00:00'\t"
+           "%r='00:00:00'\t"
 #elif defined(_AIX)
            "%r='12:00:00 AM'\t"
 #elif defined(__APPLE__)
            "%r=''\t"
+#elif defined(_WIN32)
+           "%r='12:00:00'\t"
 #else
            "%r='12:00:00 '\t"
 #endif
            "%X='00:00:00'\t"
            "%EX='00:00:00'\t"
            "%j='7'\t"
            "%Q='7'\t"
            "%q='d'\t"
            "\n"),
         lfmt,
         std::chrono::duration<int, std::ratio<86400>>(7));
 
   // Use supplied locale (ja_JP). This locale has a different alternate.
-#if defined(__APPLE__) || defined(_AIX)
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("%H='00'\t"
            "%OH='00'\t"
            "%I='12'\t"
            "%OI='12'\t"
            "%M='00'\t"
            "%OM='00'\t"
            "%S='00'\t"
            "%OS='00'\t"
 #  if defined(__APPLE__)
            "%p='AM'\t"
 #  else
            "%p='午前'\t"
 #  endif
            "%R='00:00'\t"
            "%T='00:00:00'\t"
 #  if defined(__APPLE__)
            "%r='12:00:00 AM'\t"
            "%X='00時00分00秒'\t"
            "%EX='00時00分00秒'\t"
+#  elif defined(_WIN32)
+           "%r='0:00:00'\t"
+           "%X='0:00:00'\t"
+           "%EX='0:00:00'\t"
 #  else
            "%r='午前12:00:00'\t"
            "%X='00:00:00'\t"
            "%EX='00:00:00'\t"
 #  endif
            "%j='0'\t"
            "%Q='0'\t"
            "%q='s'\t"
#  else
            "%p='午前'\t"
 #  endif
            "%R='11:59'\t"
            "%T='11:59:59'\t"
 #  if defined(__APPLE__)
            "%r='11:59:59 AM'\t"
            "%X='11時59分59秒'\t"
            "%EX='11時59分59秒'\t"
+#  elif defined(_WIN32)
+           "%r='11:59:59'\t"
+           "%X='11:59:59'\t"
+           "%EX='11:59:59'\t"
 #  else
            "%r='午前11:59:59'\t"
            "%X='11:59:59'\t"
            "%EX='11:59:59'\t"
 #  endif
            "%j='0'\t"
            "%Q='43199'\t"
            "%q='s'\t"

 #  endif
            "%R='12:00'\t"
            "%T='12:00:00'\t"
 #  if defined(__APPLE__)
            "%r='12:00:00 PM'\t"
            "%X='12時00分00秒'\t"
            "%EX='12時00分00秒'\t"
 #  else
+#    ifdef _WIN32
+           "%r='12:00:00'\t"
+#    else
            "%r='午後12:00:00'\t"
+#    endif
            "%X='12:00:00'\t"
            "%EX='12:00:00'\t"
 #  endif
            "%j='0'\t"
            "%Q='12'\t"
            "%q='h'\t"
            "\n"),
         lfmt,

 #  endif
            "%R='23:59'\t"
            "%T='23:59:59'\t"
 #  if defined(__APPLE__)
            "%r='11:59:59 PM'\t"
            "%X='23時59分59秒'\t"
            "%EX='23時59分59秒'\t"
 #  else
+#    ifdef _WIN32
+           "%r='23:59:59'\t"
+#    else
            "%r='午後11:59:59'\t"
+#    endif
            "%X='23:59:59'\t"
            "%EX='23:59:59'\t"
 #  endif
            "%j='0'\t"
            "%Q='86399'\t"
            "%q='s'\t"
            "\n"),
         lfmt,
#  else
            "%p='午前'\t"
 #  endif
            "%R='00:00'\t"
            "%T='00:00:00'\t"
 #  if defined(__APPLE__)
            "%r='12:00:00 AM'\t"
            "%X='00時00分00秒'\t"
            "%EX='00時00分00秒'\t"
+#  elif defined(_WIN32)
+           "%r='0:00:00'\t"
+           "%X='0:00:00'\t"
+           "%EX='0:00:00'\t"
 #  else
            "%r='午前12:00:00'\t"
            "%X='00:00:00'\t"
            "%EX='00:00:00'\t"
 #  endif
            "%j='7'\t"
            "%Q='7'\t"
            "%q='d'\t"
            "\n"),
         lfmt,
         std::chrono::duration<int, std::ratio<86400>>(7));
-#else // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("%H='00'\t"
            "%OH='〇'\t"
            "%I='12'\t"
            "%OI='十二'\t"
            "%M='00'\t"
            "%OM='〇'\t"
            "%S='00'\t"
check(loc,
            "%X='00時00分00秒'\t"
            "%EX='00時00分00秒'\t"
            "%j='7'\t"
            "%Q='7'\t"
            "%q='d'\t"
            "\n"),
         lfmt,
         std::chrono::duration<int, std::ratio<86400>>(7));
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
 
-#endif // defined(__APPLE__) || defined(_AIX)
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_valid_negative_integral_values() {
   // [time.format]/4 The result of formatting a std::chrono::duration instance
   // holding a negative value, or an hh_mm_ss object h for which
   // h.is_negative() is true, is equivalent to the output of the corresponding
#else
            "%p=''\t"
 #endif
            "%R='23:59'\t"
            "%T='23:59:59'\t"
 #if defined(_AIX)
            "%r='11:59:59 PM'\t"
 #elif defined(__APPLE__)
            "%r=''\t"
+#elif defined(_WIN32)
+           "%r='23:59:59'\t"
 #else
            "%r='11:59:59 '\t"
 #endif
            "%X='23:59:59'\t"
            "%EX='23:59:59'\t"
            "%j='0'\t"
            "%Q='86399'\t"
            "%q='s'\t"
            "\n"),
         lfmt,
         -(23h + 59min + 59s));
 
   // Use supplied locale (ja_JP). This locale has a different alternate.
-#if defined(__APPLE__) || defined(_AIX)
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("-%H='23'\t"
            "%OH='23'\t"
            "%I='11'\t"
            "%OI='11'\t"
            "%M='59'\t"
            "%OM='59'\t"
            "%S='59'\t"
            "%OS='59'\t"
 #  if defined(__APPLE__)
            "%p='PM'\t"
 #  else
            "%p='午後'\t"
 #  endif
            "%R='23:59'\t"
            "%T='23:59:59'\t"
 #  if defined(__APPLE__)
            "%r='11:59:59 PM'\t"
            "%X='23時59分59秒'\t"
            "%EX='23時59分59秒'\t"
+#  elif defined(_WIN32)
+           "%r='23:59:59'\t"
+           "%X='23:59:59'\t"
+           "%EX='23:59:59'\t"
 #  else
            "%r='午後11:59:59'\t"
            "%X='23:59:59'\t"
            "%EX='23:59:59'\t"
 #  endif
            "%j='0'\t"
            "%Q='86399'\t"
            "%q='s'\t"
            "\n"),
         lfmt,
         -(23h + 59min + 59s));
-#else  // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("-%H='23'\t"
            "%OH='二十三'\t"
            "%I='11'\t"
            "%OI='十一'\t"
            "%M='59'\t"
            "%OM='五十九'\t"
            "%S='59'\t"
            "%OS='五十九'\t"
            "%p='午後'\t"
            "%R='23:59'\t"
            "%T='23:59:59'\t"
            "%r='午後11時59分59秒'\t"
            "%X='23時59分59秒'\t"
            "%EX='23時59分59秒'\t"
            "%j='0'\t"
            "%Q='86399'\t"
            "%q='s'\t"
            "\n"),
         lfmt,
         -(23h + 59min + 59s));
-#endif // defined(__APPLE__) || defined(_AIX)
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_valid_fractional_values() {
   using namespace std::literals::chrono_literals;
 
   const std::locale loc(LOCALE_ja_JP_UTF_8);
static void test_valid_fractional_values() {
   check(loc, SV("00.01"), SV("{:L%S}"), std::chrono::duration<int, std::centi>(1));
   check(loc, SV("00.1"), SV("{:L%S}"), std::chrono::duration<int, std::deci>(1));
   check(loc, SV("01.1"), SV("{:L%S}"), std::chrono::duration<int, std::deci>(11));
 
   check(loc, SV("00.001"), SV("{:L%S}"), std::chrono::duration<float, std::milli>(1.123456789));
   check(loc, SV("00.011"), SV("{:L%S}"), std::chrono::duration<double, std::milli>(11.123456789));
   check(loc, SV("01"), SV("{:L%S}"), std::chrono::duration<long double>(61.123456789));
 
-#if defined(__APPLE__) || defined(_AIX)
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(SV("00.000000001"), SV("{:%OS}"), 1ns);
   check(SV("00.000000501"), SV("{:%OS}"), 501ns);
   check(SV("00.000001000"), SV("{:%OS}"), 1000ns);
   check(SV("00.000000000001"), SV("{:%OS}"), std::chrono::duration<int, std::pico>(1));
   check(SV("00.000000000000001"), SV("{:%OS}"), std::chrono::duration<int, std::femto>(1));
   check(SV("00.000000000000000001"), SV("{:%OS}"), std::chrono::duration<int, std::atto>(1));
 
   check(SV("00.001"), SV("{:%OS}"), 1ms);
   check(SV("00.01"), SV("{:%OS}"), std::chrono::duration<int, std::centi>(1));
   check(SV("00.1"), SV("{:%OS}"), std::chrono::duration<int, std::deci>(1));
   check(SV("01.1"), SV("{:%OS}"), std::chrono::duration<int, std::deci>(11));
 
   check(SV("00.001"), SV("{:%OS}"), std::chrono::duration<float, std::milli>(1.123456789));
   check(SV("00.011"), SV("{:%OS}"), std::chrono::duration<double, std::milli>(11.123456789));
   check(SV("01"), SV("{:%OS}"), std::chrono::duration<long double>(61.123456789));
-#else  // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc, SV("〇.000000001"), SV("{:L%OS}"), 1ns);
   check(loc, SV("〇.000000501"), SV("{:L%OS}"), 501ns);
   check(loc, SV("〇.000001000"), SV("{:L%OS}"), 1000ns);
   check(loc, SV("〇.000000000001"), SV("{:L%OS}"), std::chrono::duration<int, std::pico>(1));
   check(loc, SV("〇.000000000000001"), SV("{:L%OS}"), std::chrono::duration<int, std::femto>(1));
   check(loc, SV("〇.000000000000000001"), SV("{:L%OS}"), std::chrono::duration<int, std::atto>(1));
 
   check(loc, SV("〇.001"), SV("{:L%OS}"), 1ms);
   check(loc, SV("〇.01"), SV("{:L%OS}"), std::chrono::duration<int, std::centi>(1));
   check(loc, SV("〇.1"), SV("{:L%OS}"), std::chrono::duration<int, std::deci>(1));
   check(loc, SV("一.1"), SV("{:L%OS}"), std::chrono::duration<int, std::deci>(11));
 
   check(loc, SV("〇.001"), SV("{:L%OS}"), std::chrono::duration<float, std::milli>(1.123456789));
   check(loc, SV("〇.011"), SV("{:L%OS}"), std::chrono::duration<double, std::milli>(11.123456789));
   check(loc, SV("一"), SV("{:L%OS}"), std::chrono::duration<long double>(61.123456789));
-#endif // defined(__APPLE__) || defined(_AIX)
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
 
   check(loc, SV("01:05:06.000000001"), SV("{:L%T}"), 1h + 5min + 6s + 1ns);
   check(loc, SV("01:05:06.000000501"), SV("{:L%T}"), 1h + 5min + 6s + 501ns);
   check(loc, SV("01:05:06.000001000"), SV("{:L%T}"), 1h + 5min + 6s + 1000ns);
 
   check(loc, SV("01:05:06.001"), SV("{:L%T}"), 1h + 5min + 6s + 1ms);
   check(loc, SV("01:05:06.01"), SV("{:L%T}"), 1h + 5min + 6s + std::chrono::duration<int, std::centi>(1));
   check(loc, SV("01:05:06.1"), SV("{:L%T}"), 1h + 5min + 6s + std::chrono::duration<int, std::deci>(1));

libcxx/test/std/time/time.syn/formatter.file_time.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
 
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
 // TODO FMT This test should not require std::to_chars(floating-point)
 // XFAIL: availability-fp_to_chars-missing
 
-// TODO FMT Investigate Windows issues.
-// UNSUPPORTED: msvc, target={{.+}}-windows-gnu
-
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
 // <chrono>
 //
 // template<class charT> struct formatter<chrono::file_time, charT>;
 
 #include <chrono>
check(loc,
         lfmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   check(loc,
         SV("%d='13'\t%Od='十三'\t%e='13'\t%Oe='十三'\n"),
         lfmt,
         file_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
 
-#endif                                 // _WIN32
+#endif // _WIN32
 
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_valid_values_weekday() {
   using namespace std::literals::chrono_literals;
 
static void test_valid_values_day_of_year() {
   check(SV("%j='001'\n"), fmt, file_seconds(0s));             // 00:00:00 UTC Thursday, 1 January 1970
   check(SV("%j='138'\n"), fmt, file_seconds(2'000'000'000s)); // 03:33:20 UTC on Wednesday, 18 May 2033
 
   // Use the global locale (fr_FR)
   check(SV("%j='001'\n"), lfmt, file_seconds(0s));             // 00:00:00 UTC Thursday, 1 January 1970
   check(SV("%j='138'\n"), lfmt, file_seconds(2'000'000'000s)); // 03:33:20 UTC on Wednesday, 18 May 2033
 
   // Use supplied locale (ja_JP). This locale has a different alternate.
-  check(loc, SV("%j='001'\n"), lfmt, file_seconds(0s));             // 00:00:00 UTC Thursday, 1 January 1970
+  check(loc, SV("%j='001'\n"), lfmt, file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   check(loc, SV("%j='138'\n"), lfmt, file_seconds(2'000'000'000s)); // 03:33:20 UTC on Wednesday, 18 May 2033
 
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_valid_values_week() {
#endif
            "%R='23:31'\t"
            "%T='23:31:30,123'\t"
 #ifdef _WIN32
            "%r='23:31:30'\t"
 #elif defined(_AIX)
            "%r='11:31:30 PM'\t"
 #elif defined(__APPLE__)
            "%r=''\t"
+#elif defined(_WIN32)
+           "%r='23:31:30 '\t"
 #else
            "%r='11:31:30 '\t"
 #endif
            "%X='23:31:30'\t"
            "%EX='23:31:30'\t"
            "\n"),
         lfmt,
         std::chrono::sys_time<std::chrono::milliseconds>(
             1'234'567'890'123ms)); // 23:31:30 UTC on Friday, 13 February 2009
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
-#if defined(__APPLE__) || defined(_AIX)
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("%H='00'\t"
            "%OH='00'\t"
            "%I='12'\t"
            "%OI='12'\t"
            "%M='00'\t"
            "%OM='00'\t"
            "%S='00'\t"
            "%OS='00'\t"
 #  if defined(__APPLE__)
            "%p='AM'\t"
 #  else
            "%p='午前'\t"
 #  endif
            "%R='00:00'\t"
            "%T='00:00:00'\t"
 #  if defined(__APPLE__)
            "%r='12:00:00 AM'\t"
            "%X='00時00分00秒'\t"
            "%EX='00時00分00秒'\t"
+#  elif defined(_WIN32)
+           "%r='0:00:00'\t"
+           "%X='0:00:00'\t"
+           "%EX='0:00:00'\t"
 #  else
            "%r='午前12:00:00'\t"
            "%X='00:00:00'\t"
            "%EX='00:00:00'\t"
 #  endif
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(0s));
#  else
            "%p='午後'\t"
 #  endif
            "%R='23:31'\t"
            "%T='23:31:30.123'\t"
 #  if defined(__APPLE__)
            "%r='11:31:30 PM'\t"
            "%X='23時31分30秒'\t"
            "%EX='23時31分30秒'\t"
+#  elif defined(_WIN32)
+           "%r='23:31:30'\t"
+           "%X='23:31:30'\t"
+           "%EX='23:31:30'\t"
 #  else
            "%r='午後11:31:30'\t"
            "%X='23:31:30'\t"
            "%EX='23:31:30'\t"
 #  endif
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(23h + 31min + 30s + 123ms));
-#else  // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("%H='00'\t"
            "%OH='〇'\t"
            "%I='12'\t"
            "%OI='十二'\t"
            "%M='00'\t"
            "%OM='〇'\t"
            "%S='00'\t"
check(loc,
            "%T='23:31:30.123'\t"
            "%r='午後11時31分30秒'\t"
            "%X='23時31分30秒'\t"
            "%EX='23時31分30秒'\t"
            "\n"),
         lfmt,
         std::chrono::sys_time<std::chrono::milliseconds>(
             1'234'567'890'123ms)); // 23:31:30 UTC on Friday, 13 February 2009
-#endif // defined(__APPLE__) || defined(_AIX)
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
 
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_valid_values_date_time() {
   using namespace std::literals::chrono_literals;
 
static void test_valid_values_date_time() {
   check(
 // https://sourceware.org/bugzilla/show_bug.cgi?id=24054
 #if defined(__GLIBC__) && __GLIBC__ <= 2 && __GLIBC_MINOR__ < 29
       SV("%c='jeu. 01 janv. 1970 00:00:00 GMT'\t%Ec='jeu. 01 janv. 1970 00:00:00 GMT'\n"),
 #elif defined(_AIX)
       SV("%c=' 1 janvier 1970 à 00:00:00 UTC'\t%Ec=' 1 janvier 1970 à 00:00:00 UTC'\n"),
 #elif defined(__APPLE__)
       SV("%c='Jeu  1 jan 00:00:00 1970'\t%Ec='Jeu  1 jan 00:00:00 1970'\n"),
+#elif defined(_WIN32)
+      SV("%c='01/01/1970 00:00:00'\t%Ec='01/01/1970 00:00:00'\n"),
 #else
       SV("%c='jeu. 01 janv. 1970 00:00:00'\t%Ec='jeu. 01 janv. 1970 00:00:00'\n"),
 #endif
       lfmt,
       file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   check(
 // https://sourceware.org/bugzilla/show_bug.cgi?id=24054
 #if defined(__GLIBC__) && __GLIBC__ <= 2 && __GLIBC_MINOR__ < 29
       SV("%c='ven. 13 févr. 2009 23:31:30 GMT'\t%Ec='ven. 13 févr. 2009 23:31:30 GMT'\n"),
 #elif defined(_AIX)
       SV("%c='13 février 2009 à 23:31:30 UTC'\t%Ec='13 février 2009 à 23:31:30 UTC'\n"),
 #elif defined(__APPLE__)
       SV("%c='Ven 13 fév 23:31:30 2009'\t%Ec='Ven 13 fév 23:31:30 2009'\n"),
+#elif defined(_WIN32)
+      SV("%c='13/02/2009 23:31:30'\t%Ec='13/02/2009 23:31:30'\n"),
 #else
       SV("%c='ven. 13 févr. 2009 23:31:30'\t%Ec='ven. 13 févr. 2009 23:31:30'\n"),
 #endif
       lfmt,
       file_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
 #if defined(__APPLE__)
#elif defined(_AIX)                    // __APPLE__
   check(loc,
         SV("%c='1970年01月 1日 00:00:00 UTC'\t%Ec='1970年01月 1日 00:00:00 UTC'\n"),
         lfmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
   check(loc,
         SV("%c='2009年02月13日 23:31:30 UTC'\t%Ec='2009年02月13日 23:31:30 UTC'\n"),
         lfmt,
         file_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
+#elif defined(_WIN32)                  // __APPLE__
+  check(loc,
+        SV("%c='1970/01/01 0:00:00'\t%Ec='1970/01/01 0:00:00'\n"),
+        lfmt,
+        std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
+  check(loc,
+        SV("%c='2009/02/13 23:31:30'\t%Ec='2009/02/13 23:31:30'\n"),
+        lfmt,
+        std::chrono::sys_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
 #else                                  // __APPLE__
   check(loc,
         SV("%c='1970年01月01日 00時00分00秒'\t%Ec='昭和45年01月01日 00時00分00秒'\n"),
         lfmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   check(loc,
         SV("%c='2009年02月13日 23時31分30秒'\t%Ec='平成21年02月13日 23時31分30秒'\n"),
check(SV("%z='UTC'\t%Ez='UTC'\t%Oz='UTC'\t%Z='UTC'\n"),
         lfmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
   check(loc,
         SV("%z='UTC'\t%Ez='UTC'\t%Oz='UTC'\t%Z='UTC'\n"),
         lfmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
+#  elif defined(_WIN32)    // defined(_AIX)
+  // Non localized output using C-locale
+  check(SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
+        fmt,
+        file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
+
+  // Use the global locale (fr_FR)
+  check(SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
+        lfmt,
+        file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
+
+  // Use supplied locale (ja_JP). This locale has a different alternate.a
+  check(loc,
+        SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
+        lfmt,
+        file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 #  else                    // defined(_AIX)
   // Non localized output using C-locale
   check(SV("%z='+0000'\t%Ez='+0000'\t%Oz='+0000'\t%Z='UTC'\n"),
         fmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use the global locale (fr_FR)
   check(SV("%z='+0000'\t%Ez='+0000'\t%Oz='+0000'\t%Z='UTC'\n"),
         lfmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
   check(loc,
         SV("%z='+0000'\t%Ez='+0000'\t%Oz='+〇'\t%Z='UTC'\n"),
         lfmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 #  endif                   // defined(_AIX)
   std::locale::global(std::locale::classic());
-#endif                     // !defined(__APPLE__)
+#endif // !defined(__APPLE__)
 }
 
 template <class CharT>
 static void test_valid_values() {
   test_valid_values_year<CharT>();
   test_valid_values_month<CharT>();
   test_valid_values_day<CharT>();
   test_valid_values_weekday<CharT>();

libcxx/test/std/time/time.syn/formatter.local_time.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
 
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
 // TODO FMT This test should not require std::to_chars(floating-point)
 // XFAIL: availability-fp_to_chars-missing
 
-// TODO FMT Investigate Windows issues.
-// UNSUPPORTED: msvc, target={{.+}}-windows-gnu
-
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
 // <chrono>
 //
 // template<class charT> struct formatter<chrono::day, charT>;
 
 #include <chrono>
check(loc,
         lfmt,
         std::chrono::local_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   check(loc,
         SV("%d='13'\t%Od='十三'\t%e='13'\t%Oe='十三'\n"),
         lfmt,
         std::chrono::local_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
 
-#endif                                               // _WIN32
+#endif // _WIN32
 
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_valid_values_weekday() {
   using namespace std::literals::chrono_literals;
 
#endif
            "%X='23:31:30'\t"
            "%EX='23:31:30'\t"
            "\n"),
         lfmt,
         std::chrono::local_time<std::chrono::milliseconds>(
             1'234'567'890'123ms)); // 23:31:30 UTC on Friday, 13 February 2009
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
-#if defined(__APPLE__) || defined(_AIX)
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("%H='00'\t"
            "%OH='00'\t"
            "%I='12'\t"
            "%OI='12'\t"
            "%M='00'\t"
            "%OM='00'\t"
            "%S='00'\t"
            "%OS='00'\t"
 #  if defined(__APPLE__)
            "%p='AM'\t"
 #  else
            "%p='午前'\t"
 #  endif
            "%R='00:00'\t"
            "%T='00:00:00'\t"
 #  if defined(__APPLE__)
            "%r='12:00:00 AM'\t"
            "%X='00時00分00秒'\t"
            "%EX='00時00分00秒'\t"
+#  elif defined(_WIN32)
+           "%r='0:00:00'\t"
+           "%X='0:00:00'\t"
+           "%EX='0:00:00'\t"
 #  else
            "%r='午前12:00:00'\t"
            "%X='00:00:00'\t"
            "%EX='00:00:00'\t"
 #  endif
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(0s));
#  else
            "%p='午後'\t"
 #  endif
            "%R='23:31'\t"
            "%T='23:31:30.123'\t"
 #  if defined(__APPLE__)
            "%r='11:31:30 PM'\t"
            "%X='23時31分30秒'\t"
            "%EX='23時31分30秒'\t"
+#  elif defined(_WIN32)
+           "%r='23:31:30'\t"
+           "%X='23:31:30'\t"
+           "%EX='23:31:30'\t"
 #  else
            "%r='午後11:31:30'\t"
            "%X='23:31:30'\t"
            "%EX='23:31:30'\t"
 #  endif
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(23h + 31min + 30s + 123ms));
-#else  // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("%H='00'\t"
            "%OH='〇'\t"
            "%I='12'\t"
            "%OI='十二'\t"
            "%M='00'\t"
            "%OM='〇'\t"
            "%S='00'\t"
check(loc,
            "%T='23:31:30.123'\t"
            "%r='午後11時31分30秒'\t"
            "%X='23時31分30秒'\t"
            "%EX='23時31分30秒'\t"
            "\n"),
         lfmt,
         std::chrono::local_time<std::chrono::milliseconds>(
             1'234'567'890'123ms)); // 23:31:30 UTC on Friday, 13 February 2009
-#endif // defined(__APPLE__) || defined(_AIX)
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
 
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_valid_values_date_time() {
   using namespace std::literals::chrono_literals;
 
static void test_valid_values_date_time() {
   check(
 // https://sourceware.org/bugzilla/show_bug.cgi?id=24054
 #if defined(__GLIBC__) && __GLIBC__ <= 2 && __GLIBC_MINOR__ < 29
       SV("%c='jeu. 01 janv. 1970 00:00:00 GMT'\t%Ec='jeu. 01 janv. 1970 00:00:00 GMT'\n"),
 #elif defined(_AIX)
       SV("%c=' 1 janvier 1970 à 00:00:00 UTC'\t%Ec=' 1 janvier 1970 à 00:00:00 UTC'\n"),
 #elif defined(__APPLE__)
       SV("%c='Jeu  1 jan 00:00:00 1970'\t%Ec='Jeu  1 jan 00:00:00 1970'\n"),
+#elif defined(_WIN32)
+      SV("%c='01/01/1970 00:00:00'\t%Ec='01/01/1970 00:00:00'\n"),
 #else
       SV("%c='jeu. 01 janv. 1970 00:00:00'\t%Ec='jeu. 01 janv. 1970 00:00:00'\n"),
 #endif
       lfmt,
       std::chrono::local_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   check(
 // https://sourceware.org/bugzilla/show_bug.cgi?id=24054
 #if defined(__GLIBC__) && __GLIBC__ <= 2 && __GLIBC_MINOR__ < 29
       SV("%c='ven. 13 févr. 2009 23:31:30 GMT'\t%Ec='ven. 13 févr. 2009 23:31:30 GMT'\n"),
 #elif defined(_AIX)
       SV("%c='13 février 2009 à 23:31:30 UTC'\t%Ec='13 février 2009 à 23:31:30 UTC'\n"),
 #elif defined(__APPLE__)
       SV("%c='Ven 13 fév 23:31:30 2009'\t%Ec='Ven 13 fév 23:31:30 2009'\n"),
+#elif defined(_WIN32)
+      SV("%c='13/02/2009 23:31:30'\t%Ec='13/02/2009 23:31:30'\n"),
 #else
       SV("%c='ven. 13 févr. 2009 23:31:30'\t%Ec='ven. 13 févr. 2009 23:31:30'\n"),
 #endif
       lfmt,
       std::chrono::local_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
 #if defined(__APPLE__)
#elif defined(_AIX)                                  // __APPLE__
   check(loc,
         SV("%c='1970年01月 1日 00:00:00 UTC'\t%Ec='1970年01月 1日 00:00:00 UTC'\n"),
         lfmt,
         std::chrono::local_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
   check(loc,
         SV("%c='2009年02月13日 23:31:30 UTC'\t%Ec='2009年02月13日 23:31:30 UTC'\n"),
         lfmt,
         std::chrono::local_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
+#elif defined(_WIN32)                                // __APPLE__
+  check(loc,
+        SV("%c='1970/01/01 0:00:00'\t%Ec='1970/01/01 0:00:00'\n"),
+        lfmt,
+        std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
+  check(loc,
+        SV("%c='2009/02/13 23:31:30'\t%Ec='2009/02/13 23:31:30'\n"),
+        lfmt,
+        std::chrono::sys_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
 #else                                                // __APPLE__
   check(loc,
         SV("%c='1970年01月01日 00時00分00秒'\t%Ec='昭和45年01月01日 00時00分00秒'\n"),
         lfmt,
         std::chrono::local_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   check(loc,
         SV("%c='2009年02月13日 23時31分30秒'\t%Ec='平成21年02月13日 23時31分30秒'\n"),

libcxx/test/std/time/time.syn/formatter.month_day.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
 
-// TODO FMT Investigate Windows issues.
-// UNSUPPORTED: msvc, target={{.+}}-windows-gnu
-
 // TODO FMT This test should not require std::to_chars(floating-point)
 // XFAIL: availability-fp_to_chars-missing
 
+// TODO FMT Investigate Windows issues.
+// XFAIL: msvc
+
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
 // <chrono>
 
 // template<class charT> struct formatter<chrono::month_day, charT>;
 
 #include <chrono>
constexpr std::basic_string_view<CharT> fmt =
       SV("{:%%b='%b'%t%%B='%B'%t%%h='%h'%t%%m='%m'%t%%Om='%Om'%t%%d='%d'%t%%e='%e'%t%%Od='%Od'%t%%Oe='%Oe'%n}");
   constexpr std::basic_string_view<CharT> lfmt =
       SV("{:L%%b='%b'%t%%B='%B'%t%%h='%h'%t%%m='%m'%t%%Om='%Om'%t%%d='%d'%t%%e='%e'%t%%Od='%Od'%t%%Oe='%Oe'%n}");
 
   const std::locale loc(LOCALE_ja_JP_UTF_8);
   std::locale::global(std::locale(LOCALE_fr_FR_UTF_8));
 
   // Non localized output using C-locale
+#ifdef _WIN32
+  check(SV("%b='Jan'\t%B='January'\t%h='Jan'\t%m='01'\t%Om='01'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        fmt,
+        std::chrono::month_day{std::chrono::January, std::chrono::day{0}});
+#else
   check(SV("%b='Jan'\t%B='January'\t%h='Jan'\t%m='01'\t%Om='01'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         fmt,
         std::chrono::month_day{std::chrono::January, std::chrono::day{0}});
+#endif
   check(SV("%b='Feb'\t%B='February'\t%h='Feb'\t%m='02'\t%Om='02'\t%d='01'\t%e=' 1'\t%Od='01'\t%Oe=' 1'\n"),
         fmt,
         std::chrono::month_day{std::chrono::February, std::chrono::day{1}});
   check(SV("%b='Mar'\t%B='March'\t%h='Mar'\t%m='03'\t%Om='03'\t%d='09'\t%e=' 9'\t%Od='09'\t%Oe=' 9'\n"),
         fmt,
         std::chrono::month_day{std::chrono::March, std::chrono::day{9}});
   check(SV("%b='Apr'\t%B='April'\t%h='Apr'\t%m='04'\t%Om='04'\t%d='10'\t%e='10'\t%Od='10'\t%Oe='10'\n"),
         fmt,
         std::chrono::month_day{std::chrono::April, std::chrono::day{10}});
   check(SV("%b='May'\t%B='May'\t%h='May'\t%m='05'\t%Om='05'\t%d='28'\t%e='28'\t%Od='28'\t%Oe='28'\n"),
         fmt,
         std::chrono::month_day{std::chrono::May, std::chrono::day{28}});
   check(SV("%b='Jun'\t%B='June'\t%h='Jun'\t%m='06'\t%Om='06'\t%d='29'\t%e='29'\t%Od='29'\t%Oe='29'\n"),
         fmt,
         std::chrono::month_day{std::chrono::June, std::chrono::day{29}});
   check(SV("%b='Jul'\t%B='July'\t%h='Jul'\t%m='07'\t%Om='07'\t%d='30'\t%e='30'\t%Od='30'\t%Oe='30'\n"),
         fmt,
         std::chrono::month_day{std::chrono::July, std::chrono::day{30}});
   check(SV("%b='Aug'\t%B='August'\t%h='Aug'\t%m='08'\t%Om='08'\t%d='31'\t%e='31'\t%Od='31'\t%Oe='31'\n"),
         fmt,
         std::chrono::month_day{std::chrono::August, std::chrono::day{31}});
+#ifdef _WIN32
+  check(SV("%b='Sep'\t%B='September'\t%h='Sep'\t%m='09'\t%Om='09'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        fmt,
+        std::chrono::month_day{std::chrono::September, std::chrono::day{32}});
+  check(SV("%b='Oct'\t%B='October'\t%h='Oct'\t%m='10'\t%Om='10'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        fmt,
+        std::chrono::month_day{std::chrono::October, std::chrono::day{99}});
+  check(SV("%b='Nov'\t%B='November'\t%h='Nov'\t%m='11'\t%Om='11'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        fmt,
+        std::chrono::month_day{std::chrono::November, std::chrono::day{100}});
+  check(SV("%b='Dec'\t%B='December'\t%h='Dec'\t%m='12'\t%Om='12'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        fmt,
+        std::chrono::month_day{std::chrono::December, std::chrono::day{255}});
+#else // _WIN32
   check(SV("%b='Sep'\t%B='September'\t%h='Sep'\t%m='09'\t%Om='09'\t%d='32'\t%e='32'\t%Od='32'\t%Oe='32'\n"),
         fmt,
         std::chrono::month_day{std::chrono::September, std::chrono::day{32}});
   check(SV("%b='Oct'\t%B='October'\t%h='Oct'\t%m='10'\t%Om='10'\t%d='99'\t%e='99'\t%Od='99'\t%Oe='99'\n"),
         fmt,
         std::chrono::month_day{std::chrono::October, std::chrono::day{99}});
-#if defined(_AIX)
+#  if defined(_AIX)
   check(SV("%b='Nov'\t%B='November'\t%h='Nov'\t%m='11'\t%Om='11'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         fmt,
         std::chrono::month_day{std::chrono::November, std::chrono::day{100}});
   check(SV("%b='Dec'\t%B='December'\t%h='Dec'\t%m='12'\t%Om='12'\t%d='55'\t%e='55'\t%Od='55'\t%Oe='55'\n"),
         fmt,
         std::chrono::month_day{std::chrono::December, std::chrono::day{255}});
-#else  //  defined(_AIX)
+#  else  //  defined(_AIX)
   check(SV("%b='Nov'\t%B='November'\t%h='Nov'\t%m='11'\t%Om='11'\t%d='100'\t%e='100'\t%Od='100'\t%Oe='100'\n"),
         fmt,
         std::chrono::month_day{std::chrono::November, std::chrono::day{100}});
   check(SV("%b='Dec'\t%B='December'\t%h='Dec'\t%m='12'\t%Om='12'\t%d='255'\t%e='255'\t%Od='255'\t%Oe='255'\n"),
         fmt,
         std::chrono::month_day{std::chrono::December, std::chrono::day{255}});
-#endif //  defined(_AIX)
+#  endif //  defined(_AIX)
+#endif   // _WIN32
 
   // Use the global locale (fr_FR)
 #if defined(__APPLE__)
   check(SV("%b='jan'\t%B='janvier'\t%h='jan'\t%m='01'\t%Om='01'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::January, std::chrono::day{0}});
   check(SV("%b='fév'\t%B='février'\t%h='fév'\t%m='02'\t%Om='02'\t%d='01'\t%e=' 1'\t%Od='01'\t%Oe=' 1'\n"),
         lfmt,
check(SV("%b='oct'\t%B='octobre'\t%h='oct'\t%m='10'\t%Om='10'\t%d='99'\t%e='99'\t%Od='99'\t%Oe='99'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::October, std::chrono::day{99}});
   check(SV("%b='nov'\t%B='novembre'\t%h='nov'\t%m='11'\t%Om='11'\t%d='100'\t%e='100'\t%Od='100'\t%Oe='100'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::November, std::chrono::day{100}});
   check(SV("%b='déc'\t%B='décembre'\t%h='déc'\t%m='12'\t%Om='12'\t%d='255'\t%e='255'\t%Od='255'\t%Oe='255'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::December, std::chrono::day{255}});
-#else    // defined(__APPLE__)
+#else // defined(__APPLE__)
+#  if defined(_WIN32)
+  check(SV("%b='janv.'\t%B='janvier'\t%h='janv.'\t%m='01'\t%Om='01'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        lfmt,
+        std::chrono::month_day{std::chrono::January, std::chrono::day{0}});
+#  else
   check(SV("%b='janv.'\t%B='janvier'\t%h='janv.'\t%m='01'\t%Om='01'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::January, std::chrono::day{0}});
+#  endif
   check(SV("%b='févr.'\t%B='février'\t%h='févr.'\t%m='02'\t%Om='02'\t%d='01'\t%e=' 1'\t%Od='01'\t%Oe=' 1'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::February, std::chrono::day{1}});
   check(SV("%b='mars'\t%B='mars'\t%h='mars'\t%m='03'\t%Om='03'\t%d='09'\t%e=' 9'\t%Od='09'\t%Oe=' 9'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::March, std::chrono::day{9}});
   check(
 #  if defined(_WIN32) || defined(_AIX)
check(SV("%b='juin'\t%B='juin'\t%h='juin'\t%m='06'\t%Om='06'\t%d='29'\t%e='29'\t%Od='29'\t%Oe='29'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::June, std::chrono::day{29}});
   check(SV("%b='juil.'\t%B='juillet'\t%h='juil.'\t%m='07'\t%Om='07'\t%d='30'\t%e='30'\t%Od='30'\t%Oe='30'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::July, std::chrono::day{30}});
   check(SV("%b='août'\t%B='août'\t%h='août'\t%m='08'\t%Om='08'\t%d='31'\t%e='31'\t%Od='31'\t%Oe='31'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::August, std::chrono::day{31}});
+#  if defined(_WIN32)
+  check(SV("%b='sept.'\t%B='septembre'\t%h='sept.'\t%m='09'\t%Om='09'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        lfmt,
+        std::chrono::month_day{std::chrono::September, std::chrono::day{32}});
+  check(SV("%b='oct.'\t%B='octobre'\t%h='oct.'\t%m='10'\t%Om='10'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        lfmt,
+        std::chrono::month_day{std::chrono::October, std::chrono::day{99}});
+  check(SV("%b='nov.'\t%B='novembre'\t%h='nov.'\t%m='11'\t%Om='11'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        lfmt,
+        std::chrono::month_day{std::chrono::November, std::chrono::day{100}});
+  check(SV("%b='déc.'\t%B='décembre'\t%h='déc.'\t%m='12'\t%Om='12'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        lfmt,
+        std::chrono::month_day{std::chrono::December, std::chrono::day{255}});
+#  else // defined(_WIN32)
   check(SV("%b='sept.'\t%B='septembre'\t%h='sept.'\t%m='09'\t%Om='09'\t%d='32'\t%e='32'\t%Od='32'\t%Oe='32'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::September, std::chrono::day{32}});
   check(SV("%b='oct.'\t%B='octobre'\t%h='oct.'\t%m='10'\t%Om='10'\t%d='99'\t%e='99'\t%Od='99'\t%Oe='99'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::October, std::chrono::day{99}});
-#  if defined(_AIX)
+#    if defined(_AIX)
   check(SV("%b='nov.'\t%B='novembre'\t%h='nov.'\t%m='11'\t%Om='11'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::November, std::chrono::day{100}});
   check(SV("%b='déc.'\t%B='décembre'\t%h='déc.'\t%m='12'\t%Om='12'\t%d='55'\t%e='55'\t%Od='55'\t%Oe='55'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::December, std::chrono::day{255}});
-#  else  //   defined(_AIX)
+#    else  //   defined(_AIX)
   check(SV("%b='nov.'\t%B='novembre'\t%h='nov.'\t%m='11'\t%Om='11'\t%d='100'\t%e='100'\t%Od='100'\t%Oe='100'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::November, std::chrono::day{100}});
   check(SV("%b='déc.'\t%B='décembre'\t%h='déc.'\t%m='12'\t%Om='12'\t%d='255'\t%e='255'\t%Od='255'\t%Oe='255'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::December, std::chrono::day{255}});
-#  endif //   defined(_AIX)
-#endif   // defined(__APPLE__)
+#    endif //   defined(_AIX)
+#  endif   //   defined(_WIN32)
+#endif     // defined(__APPLE__)
 
   // Use supplied locale (ja_JP)
 #if defined(_WIN32)
   check(loc,
-        SV("%b='1'\t%B='1月'\t%h='1'\t%m='01'\t%Om='01'\t%d='00'\t%e=' 0'\t%Od='〇'\t%Oe='〇'\n"),
+        SV("%b='1'\t%B='1月'\t%h='1'\t%m='01'\t%Om='01'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
         lfmt,
         std::chrono::month_day{std::chrono::January, std::chrono::day{0}});
   check(loc,
-        SV("%b='2'\t%B='2月'\t%h='2'\t%m='02'\t%Om='02'\t%d='01'\t%e=' 1'\t%Od='一'\t%Oe='一'\n"),
+        SV("%b='2'\t%B='2月'\t%h='2'\t%m='02'\t%Om='02'\t%d='01'\t%e=' 1'\t%Od='01'\t%Oe=' 1'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::February, std::chrono::day{1}});
   check(loc,
-        SV("%b='3'\t%B='3月'\t%h='3'\t%m='03'\t%Om='03'\t%d='09'\t%e=' 9'\t%Od='九'\t%Oe='九'\n"),
+        SV("%b='3'\t%B='3月'\t%h='3'\t%m='03'\t%Om='03'\t%d='09'\t%e=' 9'\t%Od='09'\t%Oe=' 9'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::March, std::chrono::day{9}});
   check(loc,
-        SV("%b='4'\t%B='4月'\t%h='4'\t%m='04'\t%Om='04'\t%d='10'\t%e='10'\t%Od='十'\t%Oe='十'\n"),
+        SV("%b='4'\t%B='4月'\t%h='4'\t%m='04'\t%Om='04'\t%d='10'\t%e='10'\t%Od='10'\t%Oe='10'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::April, std::chrono::day{10}});
   check(loc,
-        SV("%b='5'\t%B='5月'\t%h='5'\t%m='05'\t%Om='05'\t%d='28'\t%e='28'\t%Od='二十八'\t%Oe='二十八'\n"),
+        SV("%b='5'\t%B='5月'\t%h='5'\t%m='05'\t%Om='05'\t%d='28'\t%e='28'\t%Od='28'\t%Oe='28'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::May, std::chrono::day{28}});
   check(loc,
-        SV("%b='6'\t%B='6月'\t%h='6'\t%m='06'\t%Om='06'\t%d='29'\t%e='29'\t%Od='二十九'\t%Oe='二十九'\n"),
+        SV("%b='6'\t%B='6月'\t%h='6'\t%m='06'\t%Om='06'\t%d='29'\t%e='29'\t%Od='29'\t%Oe='29'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::June, std::chrono::day{29}});
   check(loc,
-        SV("%b='7'\t%B='7月'\t%h='7'\t%m='07'\t%Om='07'\t%d='30'\t%e='30'\t%Od='三十'\t%Oe='三十'\n"),
+        SV("%b='7'\t%B='7月'\t%h='7'\t%m='07'\t%Om='07'\t%d='30'\t%e='30'\t%Od='30'\t%Oe='30'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::July, std::chrono::day{30}});
   check(loc,
-        SV("%b='8'\t%B='8月'\t%h='8'\t%m='08'\t%Om='08'\t%d='31'\t%e='31'\t%Od='三十一'\t%Oe='三十一'\n"),
+        SV("%b='8'\t%B='8月'\t%h='8'\t%m='08'\t%Om='08'\t%d='31'\t%e='31'\t%Od='31'\t%Oe='31'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::August, std::chrono::day{31}});
   check(loc,
-        SV("%b='9'\t%B='9月'\t%h='9'\t%m='09'\t%Om='09'\t%d='32'\t%e='32'\t%Od='三十二'\t%Oe='三十二'\n"),
+        SV("%b='9'\t%B='9月'\t%h='9'\t%m='09'\t%Om='09'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
         lfmt,
         std::chrono::month_day{std::chrono::September, std::chrono::day{32}});
   check(loc,
-        SV("%b='10'\t%B='10月'\t%h='10'\t%m='10'\t%Om='10'\t%d='99'\t%e='99'\t%Od='九十九'\t%Oe='九十九'\n"),
+        SV("%b='10'\t%B='10月'\t%h='10'\t%m='10'\t%Om='10'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
         lfmt,
         std::chrono::month_day{std::chrono::October, std::chrono::day{99}});
   check(loc,
-        SV("%b='11'\t%B='11月'\t%h='11'\t%m='11'\t%Om='11'\t%d='100'\t%e='100'\t%Od='100'\t%Oe='100'\n"),
+        SV("%b='11'\t%B='11月'\t%h='11'\t%m='11'\t%Om='11'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
         lfmt,
         std::chrono::month_day{std::chrono::November, std::chrono::day{100}});
   check(loc,
-        SV("%b='12'\t%B='12月'\t%h='12'\t%m='12'\t%Om='12'\t%d='255'\t%e='255'\t%Od='255'\t%Oe='255'\n"),
+        SV("%b='12'\t%B='12月'\t%h='12'\t%m='12'\t%Om='12'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
         lfmt,
         std::chrono::month_day{std::chrono::December, std::chrono::day{255}});
 #elif defined(_AIX)      // defined(_WIN32)
   check(loc,
         SV("%b='1月'\t%B='1月'\t%h='1月'\t%m='01'\t%Om='01'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         lfmt,
         std::chrono::month_day{std::chrono::January, std::chrono::day{0}});
   check(loc,

libcxx/test/std/time/time.syn/formatter.sys_time.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
 
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
 // TODO FMT This test should not require std::to_chars(floating-point)
 // XFAIL: availability-fp_to_chars-missing
 
-// TODO FMT Investigate Windows issues.
-// UNSUPPORTED: msvc, target={{.+}}-windows-gnu
-
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
 // <chrono>
 //
 // template<class charT> struct formatter<chrono::day, charT>;
 
 #include <chrono>
check(loc,
         lfmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   check(loc,
         SV("%d='13'\t%Od='十三'\t%e='13'\t%Oe='十三'\n"),
         lfmt,
         std::chrono::sys_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
 
-#endif                                             // _WIN32
+#endif // _WIN32
 
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_valid_values_weekday() {
   using namespace std::literals::chrono_literals;
 

 #endif
            "%X='23:31:30'\t"
            "%EX='23:31:30'\t"
            "\n"),
         lfmt,
         std::chrono::sys_time<std::chrono::milliseconds>(
             1'234'567'890'123ms)); // 23:31:30 UTC on Friday, 13 February 2009
 
-  // Use supplied locale (ja_JP). This locale has a different alternate.a
-#if defined(__APPLE__) || defined(_AIX)
+  // Use supplied locale (ja_JP). This locale has a different alternate.
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("%H='00'\t"
            "%OH='00'\t"
            "%I='12'\t"
            "%OI='12'\t"
            "%M='00'\t"
            "%OM='00'\t"
            "%S='00'\t"
            "%OS='00'\t"
 #  if defined(__APPLE__)
            "%p='AM'\t"
 #  else
            "%p='午前'\t"
 #  endif
            "%R='00:00'\t"
            "%T='00:00:00'\t"
 #  if defined(__APPLE__)
            "%r='12:00:00 AM'\t"
            "%X='00時00分00秒'\t"
            "%EX='00時00分00秒'\t"
+#  elif defined(_WIN32)
+           "%r='0:00:00'\t"
+           "%X='0:00:00'\t"
+           "%EX='0:00:00'\t"
 #  else
            "%r='午前12:00:00'\t"
            "%X='00:00:00'\t"
            "%EX='00:00:00'\t"
 #  endif
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(0s));
#  else
            "%p='午後'\t"
 #  endif
            "%R='23:31'\t"
            "%T='23:31:30.123'\t"
 #  if defined(__APPLE__)
            "%r='11:31:30 PM'\t"
            "%X='23時31分30秒'\t"
            "%EX='23時31分30秒'\t"
+#  elif defined(_WIN32)
+           "%r='23:31:30'\t"
+           "%X='23:31:30'\t"
+           "%EX='23:31:30'\t"
 #  else
            "%r='午後11:31:30'\t"
            "%X='23:31:30'\t"
            "%EX='23:31:30'\t"
 #  endif
            "\n"),
         lfmt,
         std::chrono::hh_mm_ss(23h + 31min + 30s + 123ms));
-#else  // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
   check(loc,
         SV("%H='00'\t"
            "%OH='〇'\t"
            "%I='12'\t"
            "%OI='十二'\t"
            "%M='00'\t"
            "%OM='〇'\t"
            "%S='00'\t"
check(loc,
            "%T='23:31:30.123'\t"
            "%r='午後11時31分30秒'\t"
            "%X='23時31分30秒'\t"
            "%EX='23時31分30秒'\t"
            "\n"),
         lfmt,
         std::chrono::sys_time<std::chrono::milliseconds>(
             1'234'567'890'123ms)); // 23:31:30 UTC on Friday, 13 February 2009
-#endif // defined(__APPLE__) || defined(_AIX)
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
 
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_valid_values_date_time() {
   using namespace std::literals::chrono_literals;
 
static void test_valid_values_date_time() {
   check(
 // https://sourceware.org/bugzilla/show_bug.cgi?id=24054
 #if defined(__GLIBC__) && __GLIBC__ <= 2 && __GLIBC_MINOR__ < 29
       SV("%c='jeu. 01 janv. 1970 00:00:00 GMT'\t%Ec='jeu. 01 janv. 1970 00:00:00 GMT'\n"),
 #elif defined(_AIX)
       SV("%c=' 1 janvier 1970 à 00:00:00 UTC'\t%Ec=' 1 janvier 1970 à 00:00:00 UTC'\n"),
 #elif defined(__APPLE__)
       SV("%c='Jeu  1 jan 00:00:00 1970'\t%Ec='Jeu  1 jan 00:00:00 1970'\n"),
+#elif defined(_WIN32)
+      SV("%c='01/01/1970 00:00:00'\t%Ec='01/01/1970 00:00:00'\n"),
 #else
       SV("%c='jeu. 01 janv. 1970 00:00:00'\t%Ec='jeu. 01 janv. 1970 00:00:00'\n"),
 #endif
       lfmt,
       std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   check(
 // https://sourceware.org/bugzilla/show_bug.cgi?id=24054
 #if defined(__GLIBC__) && __GLIBC__ <= 2 && __GLIBC_MINOR__ < 29
       SV("%c='ven. 13 févr. 2009 23:31:30 GMT'\t%Ec='ven. 13 févr. 2009 23:31:30 GMT'\n"),
 #elif defined(_AIX)
       SV("%c='13 février 2009 à 23:31:30 UTC'\t%Ec='13 février 2009 à 23:31:30 UTC'\n"),
 #elif defined(__APPLE__)
       SV("%c='Ven 13 fév 23:31:30 2009'\t%Ec='Ven 13 fév 23:31:30 2009'\n"),
+#elif defined(_WIN32)
+      SV("%c='13/02/2009 23:31:30'\t%Ec='13/02/2009 23:31:30'\n"),
 #else
       SV("%c='ven. 13 févr. 2009 23:31:30'\t%Ec='ven. 13 févr. 2009 23:31:30'\n"),
 #endif
       lfmt,
       std::chrono::sys_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
 #if defined(__APPLE__)
#elif defined(_AIX)                                // __APPLE__
   check(loc,
         SV("%c='1970年01月 1日 00:00:00 UTC'\t%Ec='1970年01月 1日 00:00:00 UTC'\n"),
         lfmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
   check(loc,
         SV("%c='2009年02月13日 23:31:30 UTC'\t%Ec='2009年02月13日 23:31:30 UTC'\n"),
         lfmt,
         std::chrono::sys_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
+#elif defined(_WIN32)                              // __APPLE__
+  check(loc,
+        SV("%c='1970/01/01 0:00:00'\t%Ec='1970/01/01 0:00:00'\n"),
+        lfmt,
+        std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
+  check(loc,
+        SV("%c='2009/02/13 23:31:30'\t%Ec='2009/02/13 23:31:30'\n"),
+        lfmt,
+        std::chrono::sys_seconds(1'234'567'890s)); // 23:31:30 UTC on Friday, 13 February 2009
 #else                                              // __APPLE__
   check(loc,
         SV("%c='1970年01月01日 00時00分00秒'\t%Ec='昭和45年01月01日 00時00分00秒'\n"),
         lfmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   check(loc,
         SV("%c='2009年02月13日 23時31分30秒'\t%Ec='平成21年02月13日 23時31分30秒'\n"),
check(SV("%z='UTC'\t%Ez='UTC'\t%Oz='UTC'\t%Z='UTC'\n"),
         lfmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
   check(loc,
         SV("%z='UTC'\t%Ez='UTC'\t%Oz='UTC'\t%Z='UTC'\n"),
         lfmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
+#  elif defined(_WIN32)                // defined(_AIX)
+  // Non localized output using C-locale
+  check(SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
+        fmt,
+        std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
+
+  // Use the global locale (fr_FR)
+  check(SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
+        lfmt,
+        std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
+
+  // Use supplied locale (ja_JP). This locale has a different alternate.a
+  check(loc,
+        SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
+        lfmt,
+        std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 #  else                                // defined(_AIX)
   // Non localized output using C-locale
   check(SV("%z='+0000'\t%Ez='+0000'\t%Oz='+0000'\t%Z='UTC'\n"),
         fmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use the global locale (fr_FR)
   check(SV("%z='+0000'\t%Ez='+0000'\t%Oz='+0000'\t%Z='UTC'\n"),
         lfmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
   check(loc,
         SV("%z='+0000'\t%Ez='+0000'\t%Oz='+〇'\t%Z='UTC'\n"),
         lfmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 #  endif                               // defined(_AIX)
   std::locale::global(std::locale::classic());
-#endif                                 // !defined(__APPLE__)
+#endif // !defined(__APPLE__)
 }
 
 template <class CharT>
 static void test_valid_values() {
   test_valid_values_year<CharT>();
   test_valid_values_month<CharT>();
   test_valid_values_day<CharT>();
   test_valid_values_weekday<CharT>();

libcxx/test/std/time/time.syn/formatter.weekday.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
 
-// TODO FMT Investigate Windows issues.
-// UNSUPPORTED: msvc, target={{.+}}-windows-gnu
-
 // TODO FMT This test should not require std::to_chars(floating-point)
 // XFAIL: availability-fp_to_chars-missing
 
+// TODO FMT Investigate Windows issues.
+// XFAIL: msvc
+
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
 // <chrono>
 
 // template<class charT> struct formatter<chrono::weekday, charT>;
 
 #include <chrono>
#if defined(__APPLE__)
 
   // Use the global locale (fr_FR)
   check(SV("%u='8'\t%Ou='8'\t%w='8'\t%Ow='8'\n"), lfmt, std::chrono::weekday(8));
   check(SV("%u='255'\t%Ou='255'\t%w='255'\t%Ow='255'\n"), lfmt, std::chrono::weekday(255));
 
   // Use supplied locale (ja_JP). This locale has a different alternate.
   check(loc, SV("%u='8'\t%Ou='8'\t%w='8'\t%Ow='8'\n"), lfmt, std::chrono::weekday(8));
   check(loc, SV("%u='255'\t%Ou='255'\t%w='255'\t%Ow='255'\n"), lfmt, std::chrono::weekday(255));
-#elif defined(_AIX)
+#elif defined(_AIX)   // defined(__APPLE__)
   // Non localized output using C-locale
   check(SV("%u='8'\t%Ou='8'\t%w='8'\t%Ow='8'\n"), fmt, std::chrono::weekday(8));
   check(SV("%u='5'\t%Ou='5'\t%w='5'\t%Ow='5'\n"), fmt, std::chrono::weekday(255));
 
   // Use the global locale (fr_FR)
   check(SV("%u='8'\t%Ou='8'\t%w='8'\t%Ow='8'\n"), lfmt, std::chrono::weekday(8));
   check(SV("%u='5'\t%Ou='5'\t%w='5'\t%Ow='5'\n"), lfmt, std::chrono::weekday(255));
 
   // Use supplied locale (ja_JP). This locale has a different alternate.
   check(loc, SV("%u='8'\t%Ou='8'\t%w='8'\t%Ow='8'\n"), lfmt, std::chrono::weekday(8));
   check(loc, SV("%u='5'\t%Ou='5'\t%w='5'\t%Ow='5'\n"), lfmt, std::chrono::weekday(255));
-#else
+#elif defined(_WIN32) // defined(__APPLE__)
+  // Non localized output using C-locale
+  check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), fmt, std::chrono::weekday(8));
+  check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), fmt, std::chrono::weekday(255));
+
+  // Use the global locale (fr_FR)
+  check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday(8));
+  check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday(255));
+
+  // Use supplied locale (ja_JP). This locale has a different alternate.
+  check(loc, SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday(8));
+  check(loc, SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday(255));
+#else                 // defined(__APPLE__)
   // Non localized output using C-locale
   check(SV("%u='1'\t%Ou='1'\t%w='8'\t%Ow='8'\n"), fmt, std::chrono::weekday(8));
   check(SV("%u='3'\t%Ou='3'\t%w='255'\t%Ow='255'\n"), fmt, std::chrono::weekday(255));
 
   // Use the global locale (fr_FR)
   check(SV("%u='1'\t%Ou='1'\t%w='8'\t%Ow='8'\n"), lfmt, std::chrono::weekday(8));
   check(SV("%u='3'\t%Ou='3'\t%w='255'\t%Ow='255'\n"), lfmt, std::chrono::weekday(255));
 
   // Use supplied locale (ja_JP). This locale has a different alternate.
   check(loc, SV("%u='1'\t%Ou='一'\t%w='8'\t%Ow='八'\n"), lfmt, std::chrono::weekday(8));
   check(loc, SV("%u='3'\t%Ou='三'\t%w='255'\t%Ow='255'\n"), lfmt, std::chrono::weekday(255));
-
-#endif
+#endif                // defined(__APPLE__)
 
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test() {
   test_no_chrono_specs<CharT>();
   test_valid_values<CharT>();

libcxx/test/std/time/time.syn/formatter.weekday_index.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
 
-// TODO FMT Investigate Windows issues.
-// UNSUPPORTED: msvc, target={{.+}}-windows-gnu
-
 // TODO FMT This test should not require std::to_chars(floating-point)
 // XFAIL: availability-fp_to_chars-missing
 
+// TODO FMT Investigate Windows issues.
+// XFAIL: msvc
+
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
 // <chrono>
 
 // template<class charT> struct formatter<chrono::weekday_index, charT>;
 
 #include <chrono>
#if defined(__APPLE__)
     check(loc,
           SV("%u='255'\t%Ou='255'\t%w='255'\t%Ow='255'\n"),
           lfmt,
           std::chrono::weekday_indexed{std::chrono::weekday(255), 0});
     check(loc,
           SV("%u='255'\t%Ou='255'\t%w='255'\t%Ow='255'\n"),
           lfmt,
           std::chrono::weekday_indexed{std::chrono::weekday(255), 1});
+#elif defined(_WIN32) //  defined(__APPLE__)
+    // Non localized output using C-locale
+    check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), fmt, std::chrono::weekday_indexed{std::chrono::weekday(8), 0});
+    check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), fmt, std::chrono::weekday_indexed{std::chrono::weekday(8), 1});
+    check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), fmt, std::chrono::weekday_indexed{std::chrono::weekday(255), 0});
+    check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), fmt, std::chrono::weekday_indexed{std::chrono::weekday(255), 1});
+
+    // Use the global locale (fr_FR)
+    check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_indexed{std::chrono::weekday(8), 0});
+    check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_indexed{std::chrono::weekday(8), 1});
+    check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_indexed{std::chrono::weekday(255), 0});
+    check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_indexed{std::chrono::weekday(255), 1});
+
+    // Use supplied locale (ja_JP). This locale has a different alternate.
+    check(loc, SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_indexed{std::chrono::weekday(8), 0});
+    check(loc, SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_indexed{std::chrono::weekday(8), 1});
+    check(loc, SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_indexed{std::chrono::weekday(255), 0});
+    check(loc, SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_indexed{std::chrono::weekday(255), 1});
 #elif defined(_AIX) //  defined(__APPLE__)
     // Non localized output using C-locale
     check(SV("%u='8'\t%Ou='8'\t%w='8'\t%Ow='8'\n"), fmt, std::chrono::weekday_indexed{std::chrono::weekday(8), 0});
     check(SV("%u='8'\t%Ou='8'\t%w='8'\t%Ow='8'\n"), fmt, std::chrono::weekday_indexed{std::chrono::weekday(8), 1});
     check(SV("%u='5'\t%Ou='5'\t%w='5'\t%Ow='5'\n"), fmt, std::chrono::weekday_indexed{std::chrono::weekday(255), 0});
     check(SV("%u='5'\t%Ou='5'\t%w='5'\t%Ow='5'\n"), fmt, std::chrono::weekday_indexed{std::chrono::weekday(255), 1});
 
     // Use the global locale (fr_FR)

libcxx/test/std/time/time.syn/formatter.weekday_last.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
 
-// TODO FMT Investigate Windows issues.
-// UNSUPPORTED: msvc, target={{.+}}-windows-gnu
-
 // TODO FMT This test should not require std::to_chars(floating-point)
 // XFAIL: availability-fp_to_chars-missing
 
+// TODO FMT Investigate Windows issues.
+// XFAIL: msvc
+
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
 // <chrono>
 
 // template<class charT> struct formatter<chrono::weekday_last, charT>;
 
 #include <chrono>
#if defined(__APPLE__)
   check(SV("%u='255'\t%Ou='255'\t%w='255'\t%Ow='255'\n"), lfmt, std::chrono::weekday_last{std::chrono::weekday(255)});
 
   // Use supplied locale (ja_JP). This locale has a different alternate.
   check(loc, SV("%u='8'\t%Ou='8'\t%w='8'\t%Ow='8'\n"), lfmt, std::chrono::weekday_last{std::chrono::weekday(8)});
   check(loc,
         SV("%u='255'\t%Ou='255'\t%w='255'\t%Ow='255'\n"),
         lfmt,
         std::chrono::weekday_last{std::chrono::weekday(255)});
+#elif defined(_WIN32) // defined(__APPLE__)
+  // Non localized output using C-locale
+  check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), fmt, std::chrono::weekday_last{std::chrono::weekday(8)});
+  check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), fmt, std::chrono::weekday_last{std::chrono::weekday(255)});
+
+  // Use the global locale (fr_FR)
+  check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_last{std::chrono::weekday(8)});
+  check(SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_last{std::chrono::weekday(255)});
+
+  // Use supplied locale (ja_JP). This locale has a different alternate.
+  check(loc, SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_last{std::chrono::weekday(8)});
+  check(loc, SV("%u=''\t%Ou=''\t%w=''\t%Ow=''\n"), lfmt, std::chrono::weekday_last{std::chrono::weekday(255)});
 #elif defined(_AIX) // defined(__APPLE__)
   // Non localized output using C-locale
   check(SV("%u='8'\t%Ou='8'\t%w='8'\t%Ow='8'\n"), fmt, std::chrono::weekday_last{std::chrono::weekday(8)});
   check(SV("%u='5'\t%Ou='5'\t%w='5'\t%Ow='5'\n"), fmt, std::chrono::weekday_last{std::chrono::weekday(255)});
 
   // Use the global locale (fr_FR)
   check(SV("%u='8'\t%Ou='8'\t%w='8'\t%Ow='8'\n"), lfmt, std::chrono::weekday_last{std::chrono::weekday(8)});
   check(SV("%u='5'\t%Ou='5'\t%w='5'\t%Ow='5'\n"), lfmt, std::chrono::weekday_last{std::chrono::weekday(255)});

libcxx/test/std/time/time.syn/formatter.year_month_day.pass.cpp

 //===----------------------------------------------------------------------===//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-localization
 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
 
-// TODO FMT Investigate Windows issues.
-// UNSUPPORTED: msvc, target={{.+}}-windows-gnu
-
 // TODO FMT This test should not require std::to_chars(floating-point)
 // XFAIL: availability-fp_to_chars-missing
 
+// TODO FMT Investigate Windows issues.
+// XFAIL: msvc
+
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ja_JP.UTF-8
 
 // <chrono>
 
 // template<class charT> struct formatter<chrono::year_month_day, charT>;
 
 #include <chrono>
static void test_no_chrono_specs() {
   check(SV("*1970-02-31 is not a valid date*"),
         SV("{:*^32}"),
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{2}, std::chrono::day{31}});
   check(SV("*1970-02-31 is not a valid date"),
         SV("{:*>31}"),
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{2}, std::chrono::day{31}});
 
   // Valid year, invalid month, valid day
+#ifdef _WIN32
+  check(SV(" is not a valid date"),
+        SV("{}"),
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{31}});
+  check(SV("****** is not a valid date******"),
+        SV("{:*^32}"),
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{31}});
+  check(SV("*********** is not a valid date"),
+        SV("{:*>31}"),
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{31}});
+#else  // _WIN32
   check(SV("1970-00-31 is not a valid date"),
         SV("{}"),
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{31}});
   check(SV("*1970-00-31 is not a valid date*"),
         SV("{:*^32}"),
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{31}});
   check(SV("*1970-00-31 is not a valid date"),
         SV("{:*>31}"),
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{31}});
+#endif // _WIN32
 
   // Valid year, invalid month, invalid day
+#ifdef _WIN32
+  check(SV(" is not a valid date"),
+        SV("{}"),
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{32}});
+  check(SV("****** is not a valid date******"),
+        SV("{:*^32}"),
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{32}});
+  check(SV("*********** is not a valid date"),
+        SV("{:*>31}"),
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{32}});
+#else  // _WIN32
   check(SV("1970-00-32 is not a valid date"),
         SV("{}"),
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{32}});
   check(SV("*1970-00-32 is not a valid date*"),
         SV("{:*^32}"),
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{32}});
   check(SV("*1970-00-32 is not a valid date"),
         SV("{:*>31}"),
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::month{0}, std::chrono::day{32}});
+#endif // _WIN32
 
   // Invalid year, valid month, valid day
   check(SV("-32768-01-31 is not a valid date"),
         SV("{}"),
         std::chrono::year_month_day{std::chrono::year{-32768}, std::chrono::month{1}, std::chrono::day{31}});
   check(SV("*-32768-01-31 is not a valid date*"),
         SV("{:*^34}"),
         std::chrono::year_month_day{std::chrono::year{-32768}, std::chrono::month{1}, std::chrono::day{31}});
constexpr std::basic_string_view<CharT> fmt =
       SV("{:%%b='%b'%t%%B='%B'%t%%h='%h'%t%%m='%m'%t%%Om='%Om'%t%%d='%d'%t%%e='%e'%t%%Od='%Od'%t%%Oe='%Oe'%n}");
   constexpr std::basic_string_view<CharT> lfmt =
       SV("{:L%%b='%b'%t%%B='%B'%t%%h='%h'%t%%m='%m'%t%%Om='%Om'%t%%d='%d'%t%%e='%e'%t%%Od='%Od'%t%%Oe='%Oe'%n}");
 
   const std::locale loc(LOCALE_ja_JP_UTF_8);
   std::locale::global(std::locale(LOCALE_fr_FR_UTF_8));
 
   // Non localized output using C-locale
+#ifdef _WIN32
+  check(SV("%b='Jan'\t%B='January'\t%h='Jan'\t%m='01'\t%Om='01'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        fmt,
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::January, std::chrono::day{0}});
+#else
   check(SV("%b='Jan'\t%B='January'\t%h='Jan'\t%m='01'\t%Om='01'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::January, std::chrono::day{0}});
+#endif
   check(SV("%b='Feb'\t%B='February'\t%h='Feb'\t%m='02'\t%Om='02'\t%d='01'\t%e=' 1'\t%Od='01'\t%Oe=' 1'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::February, std::chrono::day{1}});
   check(SV("%b='Mar'\t%B='March'\t%h='Mar'\t%m='03'\t%Om='03'\t%d='09'\t%e=' 9'\t%Od='09'\t%Oe=' 9'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::March, std::chrono::day{9}});
   check(SV("%b='Apr'\t%B='April'\t%h='Apr'\t%m='04'\t%Om='04'\t%d='10'\t%e='10'\t%Od='10'\t%Oe='10'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::April, std::chrono::day{10}});
   check(SV("%b='May'\t%B='May'\t%h='May'\t%m='05'\t%Om='05'\t%d='28'\t%e='28'\t%Od='28'\t%Oe='28'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::May, std::chrono::day{28}});
   check(SV("%b='Jun'\t%B='June'\t%h='Jun'\t%m='06'\t%Om='06'\t%d='29'\t%e='29'\t%Od='29'\t%Oe='29'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::June, std::chrono::day{29}});
   check(SV("%b='Jul'\t%B='July'\t%h='Jul'\t%m='07'\t%Om='07'\t%d='30'\t%e='30'\t%Od='30'\t%Oe='30'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::July, std::chrono::day{30}});
   check(SV("%b='Aug'\t%B='August'\t%h='Aug'\t%m='08'\t%Om='08'\t%d='31'\t%e='31'\t%Od='31'\t%Oe='31'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::August, std::chrono::day{31}});
+#ifdef _WIN32
+  check(SV("%b='Sep'\t%B='September'\t%h='Sep'\t%m='09'\t%Om='09'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        fmt,
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::September, std::chrono::day{32}});
+  check(SV("%b='Oct'\t%B='October'\t%h='Oct'\t%m='10'\t%Om='10'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        fmt,
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::October, std::chrono::day{99}});
+  check(SV("%b='Nov'\t%B='November'\t%h='Nov'\t%m='11'\t%Om='11'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        fmt,
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::November, std::chrono::day{100}});
+  check(SV("%b='Dec'\t%B='December'\t%h='Dec'\t%m='12'\t%Om='12'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        fmt,
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::December, std::chrono::day{255}});
+#else // _WIN32
   check(SV("%b='Sep'\t%B='September'\t%h='Sep'\t%m='09'\t%Om='09'\t%d='32'\t%e='32'\t%Od='32'\t%Oe='32'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::September, std::chrono::day{32}});
   check(SV("%b='Oct'\t%B='October'\t%h='Oct'\t%m='10'\t%Om='10'\t%d='99'\t%e='99'\t%Od='99'\t%Oe='99'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::October, std::chrono::day{99}});
-#if defined(_AIX)
+#  if defined(_AIX)
   check(SV("%b='Nov'\t%B='November'\t%h='Nov'\t%m='11'\t%Om='11'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::November, std::chrono::day{100}});
   check(SV("%b='Dec'\t%B='December'\t%h='Dec'\t%m='12'\t%Om='12'\t%d='55'\t%e='55'\t%Od='55'\t%Oe='55'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::December, std::chrono::day{255}});
-#else  //  defined(_AIX)
+#  else  //  defined(_AIX)
   check(SV("%b='Nov'\t%B='November'\t%h='Nov'\t%m='11'\t%Om='11'\t%d='100'\t%e='100'\t%Od='100'\t%Oe='100'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::November, std::chrono::day{100}});
   check(SV("%b='Dec'\t%B='December'\t%h='Dec'\t%m='12'\t%Om='12'\t%d='255'\t%e='255'\t%Od='255'\t%Oe='255'\n"),
         fmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::December, std::chrono::day{255}});
-#endif //  defined(_AIX)
+#  endif //  defined(_AIX)
+#endif   // _WIN32
 
   // Use the global locale (fr_FR)
 #if defined(__APPLE__)
   check(SV("%b='jan'\t%B='janvier'\t%h='jan'\t%m='01'\t%Om='01'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::January, std::chrono::day{0}});
   check(SV("%b='fév'\t%B='février'\t%h='fév'\t%m='02'\t%Om='02'\t%d='01'\t%e=' 1'\t%Od='01'\t%Oe=' 1'\n"),
         lfmt,
check(SV("%b='oct'\t%B='octobre'\t%h='oct'\t%m='10'\t%Om='10'\t%d='99'\t%e='99'\t%Od='99'\t%Oe='99'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::October, std::chrono::day{99}});
   check(SV("%b='nov'\t%B='novembre'\t%h='nov'\t%m='11'\t%Om='11'\t%d='100'\t%e='100'\t%Od='100'\t%Oe='100'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::November, std::chrono::day{100}});
   check(SV("%b='déc'\t%B='décembre'\t%h='déc'\t%m='12'\t%Om='12'\t%d='255'\t%e='255'\t%Od='255'\t%Oe='255'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::December, std::chrono::day{255}});
-#else    // defined(__APPLE__)
+#else // defined(__APPLE__)
+#  ifdef _WIN32
+  check(SV("%b='janv.'\t%B='janvier'\t%h='janv.'\t%m='01'\t%Om='01'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        lfmt,
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::January, std::chrono::day{0}});
+#  else
   check(SV("%b='janv.'\t%B='janvier'\t%h='janv.'\t%m='01'\t%Om='01'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::January, std::chrono::day{0}});
+#  endif
   check(SV("%b='févr.'\t%B='février'\t%h='févr.'\t%m='02'\t%Om='02'\t%d='01'\t%e=' 1'\t%Od='01'\t%Oe=' 1'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::February, std::chrono::day{1}});
   check(SV("%b='mars'\t%B='mars'\t%h='mars'\t%m='03'\t%Om='03'\t%d='09'\t%e=' 9'\t%Od='09'\t%Oe=' 9'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::March, std::chrono::day{9}});
   check(
 #  if defined(_WIN32) || defined(_AIX)
check(SV("%b='juin'\t%B='juin'\t%h='juin'\t%m='06'\t%Om='06'\t%d='29'\t%e='29'\t%Od='29'\t%Oe='29'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::June, std::chrono::day{29}});
   check(SV("%b='juil.'\t%B='juillet'\t%h='juil.'\t%m='07'\t%Om='07'\t%d='30'\t%e='30'\t%Od='30'\t%Oe='30'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::July, std::chrono::day{30}});
   check(SV("%b='août'\t%B='août'\t%h='août'\t%m='08'\t%Om='08'\t%d='31'\t%e='31'\t%Od='31'\t%Oe='31'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::August, std::chrono::day{31}});
+#  ifdef _WIN32
+  check(SV("%b='sept.'\t%B='septembre'\t%h='sept.'\t%m='09'\t%Om='09'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        lfmt,
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::September, std::chrono::day{32}});
+  check(SV("%b='oct.'\t%B='octobre'\t%h='oct.'\t%m='10'\t%Om='10'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        lfmt,
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::October, std::chrono::day{99}});
+  check(SV("%b='nov.'\t%B='novembre'\t%h='nov.'\t%m='11'\t%Om='11'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        lfmt,
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::November, std::chrono::day{100}});
+  check(SV("%b='déc.'\t%B='décembre'\t%h='déc.'\t%m='12'\t%Om='12'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
+        lfmt,
+        std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::December, std::chrono::day{255}});
+#  else // _WIN32
   check(SV("%b='sept.'\t%B='septembre'\t%h='sept.'\t%m='09'\t%Om='09'\t%d='32'\t%e='32'\t%Od='32'\t%Oe='32'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::September, std::chrono::day{32}});
   check(SV("%b='oct.'\t%B='octobre'\t%h='oct.'\t%m='10'\t%Om='10'\t%d='99'\t%e='99'\t%Od='99'\t%Oe='99'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::October, std::chrono::day{99}});
-#  if defined(_AIX)
+#    if defined(_AIX)
   check(SV("%b='nov.'\t%B='novembre'\t%h='nov.'\t%m='11'\t%Om='11'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::November, std::chrono::day{100}});
   check(SV("%b='déc.'\t%B='décembre'\t%h='déc.'\t%m='12'\t%Om='12'\t%d='55'\t%e='55'\t%Od='55'\t%Oe='55'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::December, std::chrono::day{255}});
-#  else  //   defined(_AIX)
+#    else  //   defined(_AIX)
   check(SV("%b='nov.'\t%B='novembre'\t%h='nov.'\t%m='11'\t%Om='11'\t%d='100'\t%e='100'\t%Od='100'\t%Oe='100'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::November, std::chrono::day{100}});
   check(SV("%b='déc.'\t%B='décembre'\t%h='déc.'\t%m='12'\t%Om='12'\t%d='255'\t%e='255'\t%Od='255'\t%Oe='255'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::December, std::chrono::day{255}});
-#  endif //   defined(_AIX)
-#endif   // defined(__APPLE__)
+#    endif //   defined(_AIX)
+#  endif   // _WIN32
+#endif     // defined(__APPLE__)
 
   // Use supplied locale (ja_JP)
 #if defined(_WIN32)
   check(loc,
-        SV("%b='1'\t%B='1月'\t%h='1'\t%m='01'\t%Om='01'\t%d='00'\t%e=' 0'\t%Od='〇'\t%Oe='〇'\n"),
+        SV("%b='1'\t%B='1月'\t%h='1'\t%m='01'\t%Om='01'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::January, std::chrono::day{0}});
   check(loc,
-        SV("%b='2'\t%B='2月'\t%h='2'\t%m='02'\t%Om='02'\t%d='01'\t%e=' 1'\t%Od='一'\t%Oe='一'\n"),
+        SV("%b='2'\t%B='2月'\t%h='2'\t%m='02'\t%Om='02'\t%d='01'\t%e=' 1'\t%Od='01'\t%Oe=' 1'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::February, std::chrono::day{1}});
   check(loc,
-        SV("%b='3'\t%B='3月'\t%h='3'\t%m='03'\t%Om='03'\t%d='09'\t%e=' 9'\t%Od='九'\t%Oe='九'\n"),
+        SV("%b='3'\t%B='3月'\t%h='3'\t%m='03'\t%Om='03'\t%d='09'\t%e=' 9'\t%Od='09'\t%Oe=' 9'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::March, std::chrono::day{9}});
   check(loc,
-        SV("%b='4'\t%B='4月'\t%h='4'\t%m='04'\t%Om='04'\t%d='10'\t%e='10'\t%Od='十'\t%Oe='十'\n"),
+        SV("%b='4'\t%B='4月'\t%h='4'\t%m='04'\t%Om='04'\t%d='10'\t%e='10'\t%Od='10'\t%Oe='10'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::April, std::chrono::day{10}});
   check(loc,
-        SV("%b='5'\t%B='5月'\t%h='5'\t%m='05'\t%Om='05'\t%d='28'\t%e='28'\t%Od='二十八'\t%Oe='二十八'\n"),
+        SV("%b='5'\t%B='5月'\t%h='5'\t%m='05'\t%Om='05'\t%d='28'\t%e='28'\t%Od='28'\t%Oe='28'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::May, std::chrono::day{28}});
   check(loc,
-        SV("%b='6'\t%B='6月'\t%h='6'\t%m='06'\t%Om='06'\t%d='29'\t%e='29'\t%Od='二十九'\t%Oe='二十九'\n"),
+        SV("%b='6'\t%B='6月'\t%h='6'\t%m='06'\t%Om='06'\t%d='29'\t%e='29'\t%Od='29'\t%Oe='29'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::June, std::chrono::day{29}});
   check(loc,
-        SV("%b='7'\t%B='7月'\t%h='7'\t%m='07'\t%Om='07'\t%d='30'\t%e='30'\t%Od='三十'\t%Oe='三十'\n"),
+        SV("%b='7'\t%B='7月'\t%h='7'\t%m='07'\t%Om='07'\t%d='30'\t%e='30'\t%Od='30'\t%Oe='30'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::July, std::chrono::day{30}});
   check(loc,
-        SV("%b='8'\t%B='8月'\t%h='8'\t%m='08'\t%Om='08'\t%d='31'\t%e='31'\t%Od='三十一'\t%Oe='三十一'\n"),
+        SV("%b='8'\t%B='8月'\t%h='8'\t%m='08'\t%Om='08'\t%d='31'\t%e='31'\t%Od='31'\t%Oe='31'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::August, std::chrono::day{31}});
   check(loc,
-        SV("%b='9'\t%B='9月'\t%h='9'\t%m='09'\t%Om='09'\t%d='32'\t%e='32'\t%Od='三十二'\t%Oe='三十二'\n"),
+        SV("%b='9'\t%B='9月'\t%h='9'\t%m='09'\t%Om='09'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::September, std::chrono::day{32}});
   check(loc,
-        SV("%b='10'\t%B='10月'\t%h='10'\t%m='10'\t%Om='10'\t%d='99'\t%e='99'\t%Od='九十九'\t%Oe='九十九'\n"),
+        SV("%b='10'\t%B='10月'\t%h='10'\t%m='10'\t%Om='10'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::October, std::chrono::day{99}});
   check(loc,
-        SV("%b='11'\t%B='11月'\t%h='11'\t%m='11'\t%Om='11'\t%d='100'\t%e='100'\t%Od='100'\t%Oe='100'\n"),
+        SV("%b='11'\t%B='11月'\t%h='11'\t%m='11'\t%Om='11'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::November, std::chrono::day{100}});
   check(loc,
-        SV("%b='12'\t%B='12月'\t%h='12'\t%m='12'\t%Om='12'\t%d='255'\t%e='255'\t%Od='255'\t%Oe='255'\n"),
+        SV("%b='12'\t%B='12月'\t%h='12'\t%m='12'\t%Om='12'\t%d=''\t%e=''\t%Od=''\t%Oe=''\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::December, std::chrono::day{255}});
 #elif defined(_AIX)      // defined(_WIN32)
   check(loc,
         SV("%b='1月'\t%B='1月'\t%h='1月'\t%m='01'\t%Om='01'\t%d='00'\t%e=' 0'\t%Od='00'\t%Oe=' 0'\n"),
         lfmt,
         std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::January, std::chrono::day{0}});
   check(loc,
check(
          "%j='001'\t"
          "%g='70'\t"
          "%G='1970'\t"
          "%u='4'\t"
          "%U='00'\t"
          "%V='01'\t"
          "%w='4'\t"
          "%W='00'\t"
-#if defined(__APPLE__) || defined(_AIX)
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "%x='1970/01/01'\t"
-#else  // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "%x='1970年01月01日'\t"
-#endif // defined(__APPLE__) || defined(_AIX)
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "%y='70'\t"
          "%Y='1970'\t"
-#if defined(__APPLE__) || defined(_AIX)
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "%Ex='1970/01/01'\t"
          "%EC='19'\t"
          "%Ey='70'\t"
          "%EY='1970'\t"
          "%Ou='4'\t"
          "%OU='00'\t"
          "%OV='01'\t"
          "%Ow='4'\t"
          "%OW='00'\t"
          "%Oy='70'\t"
-#else  // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "%Ex='昭和45年01月01日'\t"
          "%EC='昭和'\t"
          "%Ey='45'\t"
          "%EY='昭和45年'\t"
          "%Ou='四'\t"
          "%OU='〇'\t"
          "%OV='一'\t"
          "%Ow='四'\t"
          "%OW='〇'\t"
          "%Oy='七十'\t"
-#endif // defined(__APPLE__) || defined(_AIX)
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "\n"),
       lfmt,
       std::chrono::year_month_day{std::chrono::year{1970}, std::chrono::January, std::chrono::day{1}});
 
   check(
       loc,
       SV("%C='20'\t"
          "%D='05/29/04'\t"
          "%F='2004-05-29'\t"
          "%j='150'\t"
          "%g='04'\t"
          "%G='2004'\t"
          "%u='6'\t"
          "%U='21'\t"
          "%V='22'\t"
          "%w='6'\t"
          "%W='21'\t"
-#if defined(__APPLE__) || defined(_AIX)
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "%x='2004/05/29'\t"
-#else  // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "%x='2004年05月29日'\t"
-#endif // defined(__APPLE__) || defined(_AIX)
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "%y='04'\t"
          "%Y='2004'\t"
-#if defined(__APPLE__) || defined(_AIX)
+#if defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "%Ex='2004/05/29'\t"
          "%EC='20'\t"
          "%Ey='04'\t"
          "%EY='2004'\t"
          "%Ou='6'\t"
          "%OU='21'\t"
          "%OV='22'\t"
          "%Ow='6'\t"
          "%OW='21'\t"
          "%Oy='04'\t"
-#else  // defined(__APPLE__) || defined(_AIX)
+#else  // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "%Ex='平成16年05月29日'\t"
          "%EC='平成'\t"
          "%Ey='16'\t"
          "%EY='平成16年'\t"
          "%Ou='六'\t"
          "%OU='二十一'\t"
          "%OV='二十二'\t"
          "%Ow='六'\t"
          "%OW='二十一'\t"
          "%Oy='四'\t"
-#endif // defined(__APPLE__) || defined(_AIX)
+#endif // defined(__APPLE__) || defined(_AIX) || defined(_WIN32)
          "\n"),
       lfmt,
       std::chrono::year_month_day{std::chrono::year{2004}, std::chrono::May, std::chrono::day{29}});
 
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>