27 Time library [time]

27.8 The civil calendar [time.cal]

27.8.16 Class year_­month_­weekday [time.cal.ymwd]

27.8.16.2 Member functions [time.cal.ymwd.members]

constexpr year_month_weekday(const chrono::year& y, const chrono::month& m, const chrono::weekday_indexed& wdi) noexcept;
Effects: Initializes y_­ with y, m_­ with m, and wdi_­ with wdi.
constexpr year_month_weekday(const sys_days& dp) noexcept;
Effects: Constructs an object of type year_­month_­weekday which corresponds to the date represented by dp.
Remarks: For any value ymdl of type year_­month_­weekday for which ymdl.ok() is true, ymdl == year_­month_­weekday{sys_­days{ymdl}} is true.
constexpr explicit year_month_weekday(const local_days& dp) noexcept;
Effects: Equivalent to constructing with sys_­days{dp.time_­since_­epoch()}.
constexpr year_month_weekday& operator+=(const months& m) noexcept;
Effects: *this = *this + m.
Returns: *this.
constexpr year_month_weekday& operator-=(const months& m) noexcept;
Effects: *this = *this - m.
Returns: *this.
constexpr year_month_weekday& operator+=(const years& y) noexcept;
Effects: *this = *this + y.
Returns: *this.
constexpr year_month_weekday& operator-=(const years& y) noexcept;
Effects: *this = *this - y.
Returns: *this.
constexpr chrono::year year() const noexcept;
Returns: y_­.
constexpr chrono::month month() const noexcept;
Returns: m_­.
constexpr chrono::weekday weekday() const noexcept;
Returns: wdi_­.weekday().
constexpr unsigned index() const noexcept;
Returns: wdi_­.index().
constexpr chrono::weekday_indexed weekday_indexed() const noexcept;
Returns: wdi_­.
constexpr operator sys_days() const noexcept;
Returns: If y_­.ok() && m_­.ok() && wdi_­.weekday().ok(), returns a sys_­days that represents the date (index() - 1) * 7 days after the first weekday() of year()/month().
If index() is 0 the returned sys_­days represents the date 7 days prior to the first weekday() of year()/month().
Otherwise the returned value is unspecified.
constexpr explicit operator local_days() const noexcept;
Returns: local_­days{sys_­days{*this}.time_­since_­epoch()}.
constexpr bool ok() const noexcept;
Returns: If any of y_­.ok(), m_­.ok(), or wdi_­.ok() is false, returns false.
Otherwise, if *this represents a valid date, returns true.
Otherwise, returns false.