https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110149
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- It looks like I forgot to actually format using 'P' though, I only parsed it from the format string. This would fix that, and disable the P2519 changes for -std=c++20 and -std=c++23: --- a/libstdc++-v3/include/std/format +++ b/libstdc++-v3/include/std/format @@ -2081,19 +2081,29 @@ namespace __format if (__finished()) return __first; +#if __cplusplus > 202302L || ! defined __STRICT_ANSI__ // _GLIBCXX_RESOLVE_LIB_DEFECTS // P2519R3 Formatting pointers __first = __spec._M_parse_zero_fill(__first, __last); if (__finished()) return __first; +#endif __first = __spec._M_parse_width(__first, __last, __pc); - if (__first != __last && (*__first == 'p' || *__first == 'P')) + if (__first != __last) { - if (*__first == 'P') + if (*__first == 'p') + ++__first; +#if __cplusplus > 202302L || ! defined __STRICT_ANSI__ + else if (*__first == 'P')) + { + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // P2519R3 Formatting pointers __spec._M_type = __format::_Pres_P; - ++__first; + ++__first; + } +#endif } if (__finished()) @@ -2113,6 +2123,18 @@ namespace __format const int __n = __ptr - __buf; __buf[0] = '0'; __buf[1] = 'x'; +#if __cplusplus > 202302L || ! defined __STRICT_ANSI__ + if (_M_spec._M_type == _Pres_) + { + __buf[1] = 'X'; + for (auto __p = __buf + 2; __p != __res.ptr; ++__p) +#if __has_builtin(__builtin_toupper) + *__p = __builtin_toupper(*__p); +#else + *__p = std::toupper(*__p); +#endif + } +#endif basic_string_view<_CharT> __str; if constexpr (is_same_v<_CharT, char>)