NAME¶

std::chrono::year_month_day - std::chrono::year_month_day

Synopsis¶

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

The class year_month_day represents a specific year, month, and day. It is a
field-based time point, with a resolution of std::chrono::days. std::chrono::years-
and std::chrono::months-oriented arithmetic are supported directly. An implicit
conversion to and from std::chrono::sys_days allows std::chrono::days-oriented
arithmetic to be performed efficiently.

year_month_day is a TriviallyCopyable StandardLayoutType.

Member functions¶

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

Nonmember functions

operator== compares two year_month_day values
operator<=> (function)
(C++20)
operator+ adds or subtracts a year_month_day and some number of years or months
operator- (function)
(C++20)
operator<< outputs a year_month_day into a stream
(C++20) (function template)
from_stream parses a year_month_day from a stream according to the provided format
(C++20) (function template)

Helper classes¶

std::formatter<std::chrono::year_month_day> formatting support for year_month_day
(C++20) (class template specialization)
std::hash<std::chrono::year_month_day> hash support for
(C++26) std::chrono::year_month_day
(class template specialization)

Example¶

// Run this code

#include <chrono>
#include <iostream>

int main()
{
const std::chrono::time_point now{std::chrono::system_clock::now()};

const std::chrono::year_month_day ymd{std::chrono::floor<std::chrono::days>(now)};

std::cout << "Current Year: " << static_cast<int>(ymd.year()) << ", "
"Month: " << static_cast<unsigned>(ymd.month()) << ", "
"Day: " << static_cast<unsigned>(ymd.day()) << "\n"
"ymd: " << ymd << '\n';
}

Possible output:¶

Current Year: 2023, Month: 9, Day: 4
ymd: 2023-09-04