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std::literals::chrono_literals::operator""d(3) C++ Standard Libary std::literals::chrono_literals::operator""d(3)


std::literals::chrono_literals::operator""d - std::literals::chrono_literals::operator""d


Defined in header <chrono>
constexpr std::chrono::day operator ""d(unsigned long long d) (1) (since C++20)

Forms a std::chrono::day literal representing a day of the month in the calendar.


d - the day value

Return value

A std::chrono::day storing d. If d > 255, the stored value is unspecified.

Possible implementation

constexpr std::chrono::day operator ""d(unsigned long long d) noexcept
return std::chrono::day(d);


This operator is declared in the namespace std::literals::chrono_literals, where
both literals and chrono_literals are inline namespaces. Access to this operator can
be gained with using namespace std::literals, using namespace std::chrono_literals,
and using namespace std::literals::chrono_literals.

In addition, within the namespace std::chrono, the directive using namespace
literals::chrono_literals; is provided by the standard library, so that if a
programmer uses using namespace std::chrono; to gain access to the classes in the
chrono library, the corresponding literal operators become visible as well.


// Run this code

#include <iostream>
#include <chrono>

int main()
using namespace std::literals::chrono_literals;

std::cout << static_cast<unsigned>(42d) << ' '
<< static_cast<unsigned>(256d) << ' ' // unspecified
<< static_cast<unsigned>(298d) << '\n'; // unspecified

Possible output:

42 0 42

See also

constructor constructs a day
(public member function of std::chrono::day)
operator unsigned retrieves the stored day value
(public member function of std::chrono::day)