namespace std::chrono {
class month_day {
chrono::month m_;
chrono::day d_;
public:
month_day() = default;
constexpr month_day(const chrono::month& m, const chrono::day& d) noexcept;
constexpr chrono::month month() const noexcept;
constexpr chrono::day day() const noexcept;
constexpr bool ok() const noexcept;
};
}
month_day represents a specific day of a specific month,
but with an unspecified year
. month_day is a trivially copyable and standard-layout class type
.