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<i>(v) == get<i>(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<i>(v) == get<i>(w) with i being v.index().
template<class... Types> constexpr bool operator!=(const variant<Types...>& v, const variant<Types...>& w);
Requires: get<i>(v) != get<i>(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<i>(v) != get<i>(w) with i being v.index().
template<class... Types> constexpr bool operator<(const variant<Types...>& v, const variant<Types...>& w);
Requires: get<i>(v) < get<i>(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<i>(v) < get<i>(w) with i being v.index().
template<class... Types> constexpr bool operator>(const variant<Types...>& v, const variant<Types...>& w);
Requires: get<i>(v) > get<i>(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<i>(v) > get<i>(w) with i being v.index().
template<class... Types> constexpr bool operator<=(const variant<Types...>& v, const variant<Types...>& w);
Requires: get<i>(v) <= get<i>(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<i>(v) <= get<i>(w) with i being v.index().
template<class... Types> constexpr bool operator>=(const variant<Types...>& v, const variant<Types...>& w);
Requires: get<i>(v) >= get<i>(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<i>(v) >= get<i>(w) with i being v.index().