std::chrono::year::ok
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                    |   constexpr bool ok() const noexcept;  | 
(since C++20) | |
Checks if the year value stored in *this is in the valid range, i.e., [-32767, 32767].
Return value
true if the year value stored in *this is in the range [-32767, 32767]. Otherwise false.
Possible implementation
See the implementations in libstdc++, libc++, and Howard Hinnant's date.h.
class Year { short year_; // exposition-only public: bool ok() const noexcept { return year_ != std::numeric_limits<short>::min(); } /*...*/ };  | 
Example
Run this code
#include <chrono> #include <iomanip> #include <iostream> int main() { std::cout << "input year │ internal value │ ok()\n" << std::boolalpha; for (const int i : {2020, 0x8000, 0x8001, 0xFFFF, 0x18000}) { const std::chrono::year y{i}; std::cout << std::setw(10) << i << " │ " << std::setw(14) << static_cast<int>(y) << " │ " << y.ok() << '\n'; } }
Possible output:
input year │ internal value │ ok()
      2020 │           2020 │ true
     32768 │         -32768 │ false
     32769 │         -32767 │ true
     65535 │             -1 │ true
     98304 │         -32768 │ false