29 Time library [time]

29.8 The civil calendar [time.cal]

29.8.15 Class year_month_day_last [time.cal.ymdlast] Overview [time.cal.ymdlast.overview]

namespace std::chrono { class year_month_day_last { chrono::year y_; // exposition only chrono::month_day_last mdl_; // exposition only public: constexpr year_month_day_last(const chrono::year& y, const chrono::month_day_last& mdl) noexcept; constexpr year_month_day_last& operator+=(const months& m) noexcept; constexpr year_month_day_last& operator-=(const months& m) noexcept; constexpr year_month_day_last& operator+=(const years& y) noexcept; constexpr year_month_day_last& operator-=(const years& y) noexcept; constexpr chrono::year year() const noexcept; constexpr chrono::month month() const noexcept; constexpr chrono::month_day_last month_day_last() const noexcept; constexpr chrono::day day() const noexcept; constexpr operator sys_days() const noexcept; constexpr explicit operator local_days() const noexcept; constexpr bool ok() const noexcept; }; }
year_month_day_last represents the last day of a specific year and month.
year_month_day_last is a field-based time point with a resolution of days, except that it is restricted to pointing to the last day of a year and month.
[Note 1: 
year_month_day_last supports years- and months-oriented arithmetic, but not days-oriented arithmetic.
For the latter, there is a conversion to sys_days, which efficiently supports days-oriented arithmetic.
— end note]
year_month_day_last meets the Cpp17EqualityComparable (Table 28) and Cpp17LessThanComparable (Table 29) requirements.
year_month_day_last is a trivially copyable and standard-layout class type.