Defined in header <chrono>
constexpr std::chrono::year operator ""y( unsigned long long y ) noexcept;
(since C++20)

Forms a std::chrono::year literal representing a year in the proleptic Gregorian calendar.


y - the year value

Return value

A std::chrono::year initialized from int(y). If y is not in the range [-32767, 32767], the stored value is unspecified.

Possible implementation

constexpr std::chrono::year operator ""y(unsigned long long y) noexcept
    return std::chrono::year(static_cast<int>(y));


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, or
  • 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.


#include <iostream>
#include <chrono>
int main()
    using namespace std::literals;
        << int(2020y) << ' '
        << int(-220y) << ' '
        << int(3000y) << ' '
        << int(32768y) << ' '    // unspecified
        << int(65578y) << '\n';  // unspecified

Possible output:

2020 -220 3000 -32768 42

See also

constructs a year
(public member function of std::chrono::year)

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