23 General utilities library [utilities]

23.7 Variants [variant]

23.7.6 Relational operators [variant.relops]

template <class... Types> constexpr bool operator==(const variant<Types...>& v, const variant<Types...>& w);

Requires: get(v) == get(w) is a valid expression returning a type that is convertible to bool, for all i.

Returns: If v.index() != w.index(), false; otherwise if v.valueless_by_exception(), true; otherwise get(v) == get(w) with i being v.index().

template <class... Types> constexpr bool operator!=(const variant<Types...>& v, const variant<Types...>& w);

Requires: get(v) != get(w) is a valid expression returning a type that is convertible to bool, for all i.

Returns: If v.index() != w.index(), true; otherwise if v.valueless_by_exception(), false; otherwise get(v) != get(w) with i being v.index().

template <class... Types> constexpr bool operator<(const variant<Types...>& v, const variant<Types...>& w);

Requires: get(v) < get(w) is a valid expression returning a type that is convertible to bool, for all i.

Returns: If w.valueless_by_exception(), false; otherwise if v.valueless_by_exception(), true; otherwise, if v.index() < w.index(), true; otherwise if v.index() > w.index(), false; otherwise get(v) < get(w) with i being v.index().

template <class... Types> constexpr bool operator>(const variant<Types...>& v, const variant<Types...>& w);

Requires: get(v) > get(w) is a valid expression returning a type that is convertible to bool, for all i.

Returns: If v.valueless_by_exception(), false; otherwise if w.valueless_by_exception(), true; otherwise, if v.index() > w.index(), true; otherwise if v.index() < w.index(), false; otherwise get(v) > get(w) with i being v.index().

template <class... Types> constexpr bool operator<=(const variant<Types...>& v, const variant<Types...>& w);

Requires: get(v) <= get(w) is a valid expression returning a type that is convertible to bool, for all i.

Returns: If v.valueless_by_exception(), true; otherwise if w.valueless_by_exception(), false; otherwise, if v.index() < w.index(), true; otherwise if v.index() > w.index(), false; otherwise get(v) <= get(w) with i being v.index().

template <class... Types> constexpr bool operator>=(const variant<Types...>& v, const variant<Types...>& w);

Requires: get(v) >= get(w) is a valid expression returning a type that is convertible to bool, for all i.

Returns: If w.valueless_by_exception(), true; otherwise if v.valueless_by_exception(), false; otherwise, if v.index() > w.index(), true; otherwise if v.index() < w.index(), false; otherwise get(v) >= get(w) with i being v.index().