[variant.syn]

/ mostly freestanding #include <compare> / see [compare.syn] namespace std { / [variant.variant], class template variant template<class. Types> class variant; / [variant.helper], variant helper classes template<class T> struct variant_size; / not defined template<class T> struct variant_size<const T>; template<class T> constexpr size_t variant_size_v = variant_size<T>::value; template<class. Types> struct variant_size<variant<Types..>; 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> using variant_alternative_t = variant_alternative<I, T>::type; template<size_t I, class. Types> struct variant_alternative<I, variant<Types..>; inline constexpr size_t variant_npos = -1; / [variant.get], value access template<class T, class. Types> constexpr bool holds_alternative(const variant<Types..>&) noexcept; template<size_t I, class. Types> constexpr variant_alternative_t<I, variant<Types..>& get(variant<Types..>&); / freestanding-deleted template<size_t I, class. Types> constexpr variant_alternative_t<I, variant<Types..>& get(variant<Types..>&); / freestanding-deleted template<size_t I, class. Types> constexpr const variant_alternative_t<I, variant<Types..>& get(const variant<Types..>&); / freestanding-deleted template<size_t I, class. Types> constexpr const variant_alternative_t<I, variant<Types..>& get(const variant<Types..>&); / freestanding-deleted template<class T, class. Types> constexpr T& get(variant<Types..>&); / freestanding-deleted template<class T, class. Types> constexpr T&& get(variant<Types..>&); / freestanding-deleted template<class T, class. Types> constexpr const T& get(const variant<Types..>&); / freestanding-deleted template<class T, class. Types> constexpr const T&& get(const variant<Types..>&); / freestanding-deleted template<size_t I, class. Types> constexpr add_pointer_t<variant_alternative_t<I, variant<Types..> get_if(variant<Types..>*) noexcept; template<size_t I, class. Types> constexpr add_pointer_t<const variant_alternative_t<I, variant<Types..> get_if(const variant<Types..>*) noexcept; template<class T, class. Types> constexpr add_pointer_t<T> get_if(variant<Types..>*) noexcept; template<class T, class. Types> constexpr add_pointer_t<const T> get_if(const variant<Types..>*) noexcept; / [variant.relops], relational operators template<class. Types> constexpr bool operator=(const variant<Types..>&, const variant<Types..>&); template<class. Types> constexpr bool operator!=(const variant<Types..>&, const variant<Types..>&); template<class. Types> constexpr bool operator<(const variant<Types..>&, const variant<Types..>&); template<class. Types> constexpr bool operator>(const variant<Types..>&, const variant<Types..>&); template<class. Types> constexpr bool operator<=(const variant<Types..>&, const variant<Types..>&); template<class. Types> constexpr bool operator>=(const variant<Types..>&, const variant<Types..>&); template<class. Types> requires (three_way_comparable<Types> && ..) constexpr common_comparison_category_t<compare_three_way_result_t<Types>.> operator<=>(const variant<Types..>&, const variant<Types..>&); / [variant.visit], visitation template<class Visitor, class. Variants> constexpr see below visit(Visitor&&, Variants&&.); template<class R, class Visitor, class. Variants> constexpr R visit(Visitor&&, Variants&&.); / [variant.monostate], class monostate struct monostate; / [variant.monostate.relops], monostate relational operators constexpr bool operator=(monostate, monostate) noexcept; constexpr strong_ordering operator<=>(monostate, monostate) noexcept; / [variant.specalg], specialized algorithms template<class. Types> constexpr void swap(variant<Types..>&, variant<Types..>&) noexcept(see below); / [variant.bad.access], class bad_variant_access class bad_variant_access; / [variant.hash], hash support template<class T> struct hash; template<class. Types> struct hash<variant<Types..>; template<> struct hash<monostate>; }

22 General utilities library [utilities]

22.6 Variants [variant]

22.6.2 Header <variant> synopsis [variant.syn]