Function Approx

test/doctest.h:1218–1222

#ifdef DOCTEST_CONFIG_INCLUDE_TYPE_TRAITS
    template <typename T>
    explicit Approx(const T& value,
                    typename detail::types::enable_if<std::is_constructible<double, T>::value>::type* =
                            static_cast<T*>(nullptr)) {
        *this = static_cast<double>(value);
    }
#endif // DOCTEST_CONFIG_INCLUDE_TYPE_TRAITS

    Approx& epsilon(double newEpsilon);