NAME¶

std::chrono::year_month_day_last - std::chrono::year_month_day_last

Synopsis¶

Defined in header <chrono>
class year_month_day_last; (since C++20)

The class year_month_day_last represents the last day of a specific year and month.
It is a field-based time point, with a resolution of std::chrono::days, subject to
the limit that it can only represent the last day of a month.

std::chrono::years- and std::chrono::months-oriented arithmetic are supported
directly. An implicit conversion to std::chrono::sys_days allows
std::chrono::days-oriented arithmetic to be performed efficiently.

year_month_day_last is a TriviallyCopyable StandardLayoutType.

Member functions¶

constructor constructs a year_month_day_last object
(public member function)
operator+= modifies the time point by some number of months or years
operator-= (public member function)
year
month accesses the fields of this object
day (public member function)
month_day_last
operator sys_days converts to a std::chrono::time_point
operator local_days (public member function)
ok checks whether this object represents a valid date
(public member function)

Nonmember functions

operator== compares two year_month_day_last values
operator<=> (function)
(C++20)
operator+ adds or subtracts a year_month_day_last and some number of years or
operator- months
(C++20) (function)
operator<< outputs a year_month_day_last into a stream
(C++20) (function template)

Helper classes¶

formatting support for
std::formatter<std::chrono::year_month_day_last> year_month_day_last
(C++20) (class template specialization)

std::hash<std::chrono::year_month_day_last> hash support for
(C++26) std::chrono::year_month_day_last
(class template specialization)

Example¶

// Run this code

#include <chrono>
#include <iostream>

int main()
{
const auto ymd = std::chrono::year_month_day
{
std::chrono::floor<std::chrono::days>(std::chrono::system_clock::now())
};

const std::chrono::year_month_day_last ymdl
{
ymd.year(), ymd.month() / std::chrono::last
};

std::cout << "The last day of present month (" << ymdl << ") is: "
<< std::chrono::year_month_day{ymdl}.day() << '\n';

// The 'last' object can be placed wherever it is legal to place a 'day':
using namespace std::chrono;
constexpr std::chrono::year_month_day_last
ymdl1 = 2023y / February / last,
ymdl2 = last / February / 2023y,
ymdl3 = February / last / 2023y;
static_assert(ymdl1 == ymdl2 && ymdl2 == ymdl3);
}

Possible output:¶

The last day of present month (2023/Aug/last) is: 31

See also¶

year_month_day represents a specific year, month, and day
(C++20) (class)