operator==, !=, <, <=, >, >=(std::variant)

Defined in header `<variant>`
template <class... Types> constexpr bool operator==(const std::variant<Types...>& v, const std::variant<Types...>& w);	(1)	(since C++17)
template <class... Types> constexpr bool operator!=(const std::variant<Types...>& v, const std::variant<Types...>& w);	(2)	(since C++17)
template <class... Types> constexpr bool operator<(const std::variant<Types...>& v, const std::variant<Types...>& w);	(3)	(since C++17)
template <class... Types> constexpr bool operator>(const std::variant<Types...>& v, const std::variant<Types...>& w);	(4)	(since C++17)
template <class... Types> constexpr bool operator<=(const std::variant<Types...>& v, const std::variant<Types...>& w);	(5)	(since C++17)
template <class... Types> constexpr bool operator>=(const std::variant<Types...>& v, const std::variant<Types...>& w);	(6)	(since C++17)

1) Equality operator for variants:

If v.index() != w.index(), returns false;
otherwise if v.valueless_by_exception(), returns true;
otherwise returns std::get<v.index()>(v) == std::get<v.index()>(w). The behavior is undefined if std::get(v) == std::get(w) is not a valid expression returning a type convertible to bool, for any i.

2) Inequality operator for variants:

If v.index() != w.index(), returns true;
otherwise if v.valueless_by_exception(), returns false;
otherwise returns std::get<v.index()>(v) != std::get<v.index()>(w). The behavior is undefined if std::get(v) != std::get(w) is not a valid expression returning a type convertible to bool, for any i.

3) Less-than operator for variants:

If w.valueless_by_exception(), returns false;
otherwise if v.valueless_by_exception(), returns true;
otherwise if v.index() < w.index(), returns true;
otherwise if v.index() > w.index(), returns false;
otherwise returns std::get<v.index()>(v) < std::get<v.index()>(w). The behavior is undefined if std::get(v) < std::get(w) is not a valid expression returning a type convertible to bool, for any i.

4) Greater-than operator for variants:

If v.valueless_by_exception(), returns false;
otherwise if w.valueless_by_exception(), returns true;
otherwise if v.index() > w.index(), returns true;
otherwise if v.index() < w.index(), returns false;
otherwise returns std::get<v.index()>(v) > std::get<v.index()>(w). The behavior is undefined if std::get(v) > std::get(w) is not a valid expression returning a type convertible to bool, for any i.

5) Less-equal operator for variants:

If v.valueless_by_exception(), returns true;
otherwise if w.valueless_by_exception(), returns false;
otherwise if v.index() < w.index(), returns true;
otherwise if v.index() > w.index(), returns false;
otherwise returns std::get<v.index()>(v) <= std::get<v.index()>(w). The behavior is undefined if std::get(v) <= std::get(w) is not a valid expression returning a type convertible to bool, for any i.

6) Greater-equal operator for variants:

If w.valueless_by_exception(), returns true;
otherwise if v.valueless_by_exception(), returns false;
otherwise if v.index() > w.index(), returns true;
otherwise if v.index() < w.index(), returns false;
otherwise std::get<v.index()>(v) >= std::get<v.index()>(w). The behavior is undefined if std::get(v) >= std::get(w) is not a valid expression returning a type convertible to bool, for any i.

v,w

variants to compare

The boolean result of the comparison as described above.