On Wed, 2 Jul 2025 at 10:50, Jonathan Wakely <jwak...@redhat.com> wrote: > > On 02/07/25 03:36 +0300, Mateusz Zych wrote: > >Hello libstdc++ Team! > > > >I have recently found a bug in libstdc++, that is, > >the std::numeric_limits<> template specializations for integer-class types > >are missing some of static data members, > >which results in compilation errors of valid C++ code: > > > > - Compiler Explorer: https://godbolt.org/z/E7z4WYfj4 > > > >Since adding missing member constants, which are the most relevant to > >integer-like types, > >was not a lot of code, I have prepared a Git patch with relevant changes. > > > >I hope this patch is useful, Mateusz Zych > > Thanks, I don't think there was any reason to omit these members, and I > agree we should add them. > > The patch is simple and obvious enough that I don't think we need a > copyright assignment or DCO sign-off, so I'll push this to the > relevant branches. Thanks!
Oh actually the radix members should be of type int, not bool. I can fix that. > > >From 1e83287bbd6adf6ad8f483bd2f891692e0bed0c7 Mon Sep 17 00:00:00 2001 > >From: Mateusz Zych <mte.z...@gmail.com> > >Date: Wed, 2 Jul 2025 01:51:40 +0300 > >Subject: [PATCH] libstdc++: Added missing member constants to numeric_limits > > specializations for integer-class types. > > > >25.3.4.4 Concept weakly_incrementable [iterator.concept.winc] > > > > (5) For every integer-class type I, > > let B(I) be a unique hypothetical extended integer type > > of the same signedness with the same width as I. > > > > [Note 2: The corresponding > > hypothetical specialization numeric_limits<B(I)> > > meets the requirements on > > numeric_limits specializations for integral types.] > > > > (11) For every (possibly cv-qualified) integer-class type I, > > numeric_limits<I> is specialized such that: > > > > - each static data member m > > has the same value as numeric_limits<B(I)>::m, and > > > > - each static member function f > > returns I(numeric_limits<B(I)>::f()). > > > >libstdc++-v3/ChangeLog: > > > > * include/bits/max_size_type.h > > (numeric_limits<__max_size_type>): New static data members. > > (numeric_limits<__max_diff_type>): Likewise. > >--- > > libstdc++-v3/include/bits/max_size_type.h | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > >diff --git a/libstdc++-v3/include/bits/max_size_type.h > >b/libstdc++-v3/include/bits/max_size_type.h > >index 73a6d141d5b..bc7700506a2 100644 > >--- a/libstdc++-v3/include/bits/max_size_type.h > >+++ b/libstdc++-v3/include/bits/max_size_type.h > >@@ -775,6 +775,9 @@ namespace ranges > > static constexpr bool is_signed = false; > > static constexpr bool is_integer = true; > > static constexpr bool is_exact = true; > >+ static constexpr bool is_bounded = true; > >+ static constexpr bool is_modulo = true; > >+ static constexpr bool radix = 2; > > static constexpr int digits > > = __gnu_cxx::__int_traits<_Sp::__rep>::__digits + 1; > > static constexpr int digits10 > >@@ -802,6 +805,9 @@ namespace ranges > > static constexpr bool is_signed = true; > > static constexpr bool is_integer = true; > > static constexpr bool is_exact = true; > >+ static constexpr bool is_bounded = true; > >+ static constexpr bool is_modulo = false; > >+ static constexpr bool radix = 2; > > static constexpr int digits = numeric_limits<_Sp>::digits - 1; > > static constexpr int digits10 > > = static_cast<int>(digits * numbers::ln2 / numbers::ln10); > >-- > >2.48.1 > > >
