8 #ifndef BOOST_NOWIDE_DETAIL_IS_PATH_HPP_INCLUDED     9 #define BOOST_NOWIDE_DETAIL_IS_PATH_HPP_INCLUDED    11 #include <type_traits>    22             template<
typename U, U& (U::*)(), U (U::*)() const>
    25             static std::true_type test(Check<U, &U::make_preferred, &U::filename>*);
    27             static std::false_type test(...);
    29             static constexpr 
bool value = decltype(test<T>(0))::value;
    32         template<
typename Path, 
typename Result>
    33         using enable_if_path_t = 
typename std::enable_if<is_path<Path>::value, Result>::type;