On Mon, 12 Jun 2023, Ken Matsui via Libstdc++ wrote:
> This patch gets std::is_function to dispatch to new built-in trait
> __is_function.
>
> libstdc++-v3/ChangeLog:
>
> * include/std/type_traits (is_function): Use __is_function built-in
> trait.
> (is_function_v): Likewise.
LGTM
>
> Signed-off-by: Ken Matsui <kmat...@cs.washington.edu>
> ---
> libstdc++-v3/include/std/type_traits | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/libstdc++-v3/include/std/type_traits
> b/libstdc++-v3/include/std/type_traits
> index 2a14df7e5f9..954b57518de 100644
> --- a/libstdc++-v3/include/std/type_traits
> +++ b/libstdc++-v3/include/std/type_traits
> @@ -594,6 +594,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> { };
>
> /// is_function
> +#if __has_builtin(__is_function)
> + template<typename _Tp>
> + struct is_function
> + : public __bool_constant<__is_function(_Tp)>
> + { };
> +#else
> template<typename _Tp>
> struct is_function
> : public __bool_constant<!is_const<const _Tp>::value> { };
> @@ -605,6 +611,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> template<typename _Tp>
> struct is_function<_Tp&&>
> : public false_type { };
> +#endif
>
> #define __cpp_lib_is_null_pointer 201309L
>
> @@ -3197,8 +3204,14 @@ template <typename _Tp>
> inline constexpr bool is_union_v = __is_union(_Tp);
> template <typename _Tp>
> inline constexpr bool is_class_v = __is_class(_Tp);
> +
> +#if __has_builtin(__is_function)
> +template <typename _Tp>
> + inline constexpr bool is_function_v = __is_function(_Tp);
> +#else
> template <typename _Tp>
> inline constexpr bool is_function_v = is_function<_Tp>::value;
> +#endif
>
> #if __has_builtin(__is_reference)
> template <typename _Tp>
> --
> 2.41.0
>
>
