variant_alternative 構造体

Variant オブジェクトを支援します。

構文

template <size_t I, class T>
    struct variant_alternative; // not defined
template <size_t I, class T>
    struct variant_alternative<I, const T>;
template <size_t I, class T>
    struct variant_alternative<I, volatile T>;
template <size_t I, class T>
    struct variant_alternative<I, const volatile T>;
template <size_t I, class T>
    using variant_alternative_t = typename variant_alternative<I, T>::type;
template <size_t I, class... Types>
    struct variant_alternative<I, variant<Types...>>;