std::chrono::year::year (3) Linux Manual Page

std::chrono::year::year – std::chrono::year::year

Synopsis

year() = default;
(since C++ 20)

    explicit constexpr year(int y) noexcept;
(since C++ 20)

Constructs a year object.
1) Default constructor leaves the year value uninitialized.
2) If y is in the range [-32767, 32767], constructs a year object holding the year value y. Otherwise the value held is unspecified.