[{"id":3680339,"web_url":"http://patchwork.ozlabs.org/comment/3680339/","msgid":"","list_archive_url":null,"date":"2026-04-22T08:57:37","subject":"Re: [PATCH] libstdc++: Add _GLIBCXX_RESOLVE_LIB_DEFECTS for alredy\n implemented issues.","submitter":{"id":48004,"url":"http://patchwork.ozlabs.org/api/people/48004/","name":"Jonathan Wakely","email":"jwakely@redhat.com"},"content":"On Wed, 22 Apr 2026 at 09:27, Tomasz Kamiński wrote:\n>\n> This covers issue affecting pre-C+26 features that were resolved\n> during 2026 Croydon meeting.\n>\n> libstdc++-v3/ChangeLog:\n>\n> * include/bits/chrono_io.h: Add comment for LWG3831.\n> * include/bits/print.h: Add comment for LWG4549.\n> * include/std/condition_variable: Add comment for LWG3504.\n> * include/std/format: Add comments for LWG4522.\n> * include/std/inplace_vector: Add comment for LWG4122.\n> * include/std/mdspan: Add comment for LWG4314.\n> * include/std/optional: Add comment for LWG2746.\n> ---\n> OK for trunk?\n>\n> libstdc++-v3/include/bits/chrono_io.h | 2 ++\n> libstdc++-v3/include/bits/print.h | 2 ++\n> libstdc++-v3/include/std/condition_variable | 2 ++\n> libstdc++-v3/include/std/format | 4 ++++\n> libstdc++-v3/include/std/mdspan | 2 ++\n> libstdc++-v3/include/std/optional | 2 ++\n> 6 files changed, 14 insertions(+)\n>\n> diff --git a/libstdc++-v3/include/bits/chrono_io.h b/libstdc++-v3/include/bits/chrono_io.h\n> index f5a0a65a48d..1fe50ad79e0 100644\n> --- a/libstdc++-v3/include/bits/chrono_io.h\n> +++ b/libstdc++-v3/include/bits/chrono_io.h\n> @@ -1313,6 +1313,8 @@ namespace __format\n>\n> int __yi = (int)__y;\n> const bool __is_neg = __yi < 0;\n> + // _GLIBCXX_RESOLVE_LIB_DEFECTS\n> + // 3831. Two-digit formatting of negative year is ambiguous\n> __yi = __builtin_abs(__yi);\n> int __ci = __yi / 100;\n> // For floored division -123//100 is -2 and -100//100 is -1\n> diff --git a/libstdc++-v3/include/bits/print.h b/libstdc++-v3/include/bits/print.h\n> index 17567f2f554..20724844726 100644\n> --- a/libstdc++-v3/include/bits/print.h\n> +++ b/libstdc++-v3/include/bits/print.h\n> @@ -282,6 +282,8 @@ namespace __format\n> vprint_nonunicode_buffered(FILE* __stream, string_view __fmt,\n> format_args __args)\n> {\n> + // _GLIBCXX_RESOLVE_LIB_DEFECTS\n> + // 4549. vprint_nonunicode_buffered ignores its stream parameter\n\nI don't think this one needs to be here, it's almost editorial (and\nvprint_unicode_buffered wasn't even in C++23 anyway, it was added by a\nDR).\n\nThe commit summary line says \"alredy\" which should be \"already\".\n\nOK with that fixed, assuming all tests still pass (adding lines can\ncause dg-error line numbers to stop matching in tests).\n\n> __format::_Str_sink __buf;\n> std::vformat_to(__buf.out(), __fmt, __args);\n> auto __out = __buf.view();\n> diff --git a/libstdc++-v3/include/std/condition_variable b/libstdc++-v3/include/std/condition_variable\n> index 9e515123e7c..ce995ed5777 100644\n> --- a/libstdc++-v3/include/std/condition_variable\n> +++ b/libstdc++-v3/include/std/condition_variable\n> @@ -163,6 +163,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n> wait_for(unique_lock& __lock,\n> const chrono::duration<_Rep, _Period>& __rtime)\n> {\n> + // _GLIBCXX_RESOLVE_LIB_DEFECTS\n> + // 3504. condition_variable::wait_for is overspecified\n> using __dur = typename steady_clock::duration;\n> return wait_until(__lock,\n> steady_clock::now() +\n> diff --git a/libstdc++-v3/include/std/format b/libstdc++-v3/include/std/format\n> index 92add1e0a01..4627381fa9e 100644\n> --- a/libstdc++-v3/include/std/format\n> +++ b/libstdc++-v3/include/std/format\n> @@ -1718,6 +1718,8 @@ namespace __format\n> {\n> _CharT __wbuf[__buf_size];\n> size_t __n = __narrow_str.size();\n> + // _GLIBCXX_RESOLVE_LIB_DEFECTS\n> + // 4522. Clarify that `std::format` transcodes for `std::wformat_strings`\n> std::__to_wstring_numeric(__narrow_str.data(), __n, __wbuf);\n> return _M_format_int(basic_string_view<_CharT>(__wbuf, __n),\n> __prefix_len, __fc);\n> @@ -2304,6 +2306,8 @@ namespace __format\n> #ifdef _GLIBCXX_USE_WCHAR_T\n> else\n> {\n> + // _GLIBCXX_RESOLVE_LIB_DEFECTS\n> + // 4522. Clarify that `std::format` transcodes for `std::wformat_strings`\n> __wstr = std::__to_wstring_numeric(__narrow_str);\n> __str = __wstr;\n> }\n> diff --git a/libstdc++-v3/include/std/mdspan b/libstdc++-v3/include/std/mdspan\n> index f30c5e83d16..14d8edc8ad1 100644\n> --- a/libstdc++-v3/include/std/mdspan\n> +++ b/libstdc++-v3/include/std/mdspan\n> @@ -103,6 +103,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n> }\n> else\n> {\n> + // _GLIBCXX_RESOLVE_LIB_DEFECTS\n> + // 4314. Missing move in mdspan layout mapping::operator()\n> auto __ret = static_cast<_IndexType>(std::forward<_OIndexTypeRef>(__other));\n> if constexpr (std::is_signed_v<_IndexType>)\n> __glibcxx_assert(__ret >= 0);\n> diff --git a/libstdc++-v3/include/std/optional b/libstdc++-v3/include/std/optional\n> index 49ba7b6b45d..d0fa306addb 100644\n> --- a/libstdc++-v3/include/std/optional\n> +++ b/libstdc++-v3/include/std/optional\n> @@ -1145,6 +1145,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n> return *this;\n> }\n>\n> + // _GLIBCXX_RESOLVE_LIB_DEFECTS\n> + // 2746. Inconsistency between requirements for emplace between optional and variant\n> template\n> _GLIBCXX20_CONSTEXPR\n> enable_if_t, _Tp&>\n> --\n> 2.53.0\n>","headers":{"Return-Path":"","X-Original-To":["incoming@patchwork.ozlabs.org","gcc-patches@gcc.gnu.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","gcc-patches@gcc.gnu.org"],"Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=KC9LgZc7;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=2620:52:6:3111::32; helo=vm01.sourceware.org;\n envelope-from=gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org;\n receiver=patchwork.ozlabs.org)","sourceware.org;\n\tdkim=pass (1024-bit key,\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=KC9LgZc7","sourceware.org; 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