我如何要求（在 C++20 概念中）类型 T 是对浮点类型的引用？

Question

In the C++20 concepts library, there is std::floating_point<T> which "is satisfied if and only if T is a floating-point type" ( ref ). But I need T to be a reference to a floating-point type. What is a requires clause that expresses this?

Answer 1

As Davis said in the comments, just use type traits:

template <typename T>
concept is_floating_point_reference = 
    std::is_reference_v<T> &&
    std::floating_point<std::remove_reference_t<T>>;