[{"id":3677240,"web_url":"http://patchwork.ozlabs.org/comment/3677240/","msgid":"","list_archive_url":null,"date":"2026-04-14T14:43:09","subject":"Re: [PATCH] libstdc++: Define __cpp_lib_stdbit_h and\n __cpp_lib_stdckdint_h feature test macros.","submitter":{"id":48004,"url":"http://patchwork.ozlabs.org/api/people/48004/","name":"Jonathan Wakely","email":"jwakely@redhat.com"},"content":"On Tue, 14 Apr 2026 at 15:39, Tomasz Kamiński wrote:\n>\n> This implements LWG4550: Need new feature test macros for \n> and .\n>\n> libstdc++-v3/ChangeLog:\n>\n> * include/bits/version.def (stdbit_h, stdckdint_h): Define.\n> * include/bits/version.h: Regenerate.\n> * include/c_compatibility/stdbit.h (__cpp_lib_stdbit_h): Define\n> and use it in guards.\n> * include/c_compatibility/stdckdint.h (__cpp_lib_stdckdint_h):\n> Define and use it in guards.\n> ---\n> Testing on x86_64-linux. Dedicated tests 20_util/stdbit* and 26_numerics/stdckint*\n> already passes, so valus seem correct.\n\nOK. We should backport this to GCC 15 at some point too.\n\n\n>\n> libstdc++-v3/include/bits/version.def | 16 +++++++++++++++\n> libstdc++-v3/include/bits/version.h | 20 +++++++++++++++++++\n> libstdc++-v3/include/c_compatibility/stdbit.h | 8 ++++++--\n> .../include/c_compatibility/stdckdint.h | 8 ++++++--\n> 4 files changed, 48 insertions(+), 4 deletions(-)\n>\n> diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def\n> index 94fc1f85993..13dba4d6378 100644\n> --- a/libstdc++-v3/include/bits/version.def\n> +++ b/libstdc++-v3/include/bits/version.def\n> @@ -1871,6 +1871,22 @@ ftms = {\n> };\n> };\n>\n> +ftms = {\n> + name = stdbit_h;\n> + values = {\n> + v = 202603;\n> + cxxmin = 26;\n> + };\n> +};\n> +\n> +ftms = {\n> + name = stdckdint_h;\n> + values = {\n> + v = 202603;\n> + cxxmin = 26;\n> + };\n> +};\n> +\n> ftms = {\n> name = adaptor_iterator_pair_constructor;\n> values = {\n> diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h\n> index 402e67580eb..743f7e29fe2 100644\n> --- a/libstdc++-v3/include/bits/version.h\n> +++ b/libstdc++-v3/include/bits/version.h\n> @@ -2076,6 +2076,26 @@\n> #endif /* !defined(__cpp_lib_stdatomic_h) */\n> #undef __glibcxx_want_stdatomic_h\n>\n> +#if !defined(__cpp_lib_stdbit_h)\n> +# if (__cplusplus > 202302L)\n> +# define __glibcxx_stdbit_h 202603L\n> +# if defined(__glibcxx_want_all) || defined(__glibcxx_want_stdbit_h)\n> +# define __cpp_lib_stdbit_h 202603L\n> +# endif\n> +# endif\n> +#endif /* !defined(__cpp_lib_stdbit_h) */\n> +#undef __glibcxx_want_stdbit_h\n> +\n> +#if !defined(__cpp_lib_stdckdint_h)\n> +# if (__cplusplus > 202302L)\n> +# define __glibcxx_stdckdint_h 202603L\n> +# if defined(__glibcxx_want_all) || defined(__glibcxx_want_stdckdint_h)\n> +# define __cpp_lib_stdckdint_h 202603L\n> +# endif\n> +# endif\n> +#endif /* !defined(__cpp_lib_stdckdint_h) */\n> +#undef __glibcxx_want_stdckdint_h\n> +\n> #if !defined(__cpp_lib_adaptor_iterator_pair_constructor)\n> # if (__cplusplus >= 202100L) && _GLIBCXX_HOSTED\n> # define __glibcxx_adaptor_iterator_pair_constructor 202106L\n> diff --git a/libstdc++-v3/include/c_compatibility/stdbit.h b/libstdc++-v3/include/c_compatibility/stdbit.h\n> index 1fb691e36c1..fa4ec0414c6 100644\n> --- a/libstdc++-v3/include/c_compatibility/stdbit.h\n> +++ b/libstdc++-v3/include/c_compatibility/stdbit.h\n> @@ -29,7 +29,11 @@\n> #ifndef _GLIBCXX_STDBIT_H\n> #define _GLIBCXX_STDBIT_H\n>\n> -#if __cplusplus > 202302L\n> +#define __glibcxx_want_stdbit_h\n> +#include \n> +\n> +#ifdef __cpp_lib_stdbit_h // C++ >= 26\n> +\n> #include \n>\n> #define __STDC_VERSION_STDBIT_H__ 202311L\n> @@ -577,6 +581,6 @@ _GLIBCXX_STDBIT_FUNC(stdc_bit_floor);\n> _GLIBCXX_STDBIT_FUNC(stdc_bit_ceil);\n> #undef _GLIBCXX_STDBIT_FUNC\n> #endif // !DOXYGEN\n> -#endif // C++26\n> +#endif // __cpp_lib_stdbit_h\n>\n> #endif // _GLIBCXX_STDBIT_H\n> diff --git a/libstdc++-v3/include/c_compatibility/stdckdint.h b/libstdc++-v3/include/c_compatibility/stdckdint.h\n> index 5bdf4dc7b24..0f0b30cc899 100644\n> --- a/libstdc++-v3/include/c_compatibility/stdckdint.h\n> +++ b/libstdc++-v3/include/c_compatibility/stdckdint.h\n> @@ -29,7 +29,11 @@\n> #ifndef _GLIBCXX_STDCKDINT_H\n> #define _GLIBCXX_STDCKDINT_H\n>\n> -#if __cplusplus > 202302L\n> +#define __glibcxx_want_stdckdint_h\n> +#include \n> +\n> +#ifdef __cpp_lib_stdckdint_h // C++ >= 26\n> +\n> #include \n> #include \n>\n> @@ -96,6 +100,6 @@ using __gnu_cxx::ckd_sub;\n> using __gnu_cxx::ckd_mul;\n> #endif\n>\n> -#endif // C++26\n> +#endif // __cpp_lib_stdckdint_h\n>\n> #endif // _GLIBCXX_STDCKDINT_H\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=WTX47dt7;\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; 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