std::literals::chrono_literals::operator""y(3)

NAME
std::literals::chrono_literals::operator""y - std::literals::chrono_literals::operator""y

Synopsis
   Defined in header <chrono>
   constexpr std::chrono::year operator""y( unsigned long long y ) (since C++20)
   noexcept;
   Forms a std::chrono::year literal representing a year in the proleptic Gregorian
   calendar.

Parameters
   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));
   }

Notes
   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.

Example

// Run this code
 #include <chrono>
 #include <iostream>

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

     std::cout << int(2020y) << '\t' << 2020y << '\n'
               << int(-220y) << '\t' << -220y << '\n'
               << int(3000y) << '\t' << 3000y << '\n'
               << int(32768y) << '\t' << 32768y << '\n' // unspecified
               << int(65578y) << '\t' << 65578y << '\n'; // unspecified
 }

Possible output:
 2020 2020
 -220 -0220
 3000 3000
 -32768 -32768 is not a valid year
 42 0042

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