std::chrono::year_month_weekday::operator sys_days, std::chrono::year_month_weekday::operator local_days
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std::chrono::year_month_weekday
Member functions
year_month_weekday::operator sys_daysyear_month_weekday::operator local_days
Nonmember functions
Helper classes
constexpr operator std::chrono::sys_days () const noexcept;
(1)
(since C++20)
constexpr explicit operator std::chrono::local_days () const noexcept;
(2)
(since C++20)
Converts *this to a std::chrono::time_point representing the same date as this year_month_weekday.
1) If year().ok() && month().ok() && weekday().ok():
- If index() == 0, returns a
sys_daysthat represents the date 7 days prior to the firstweekday()of the year and month. - Else, returns a
sys_daysthat represents the date (index() - 1) * 7 days after the first weekday() of the year and month.
- If index() == 0, returns a
Otherwise, the returned value is unspecified.
2) Same as (1), but returns
local_days instead of sys_days. Equivalent to local_days(sys_days(*this).time_since_epoch()).[edit] Example
Run this code
#include <chrono> #include <iostream> using namespace std::chrono; int main() { constexpr auto ymwd{Tuesday[2]/11/2021}; std::cout << ymwd << '\n'; // convert from field-based to serial-based to add hours constexpr auto sd = sys_days{ymwd} + 24h; std::cout << sd << '\n'; constexpr auto ymd = floor<days>(sd); static_assert(ymd == November/10/2021); }
Output:
2021/Nov/Tue[2] 2021年11月10日 00:00:00