std::chrono::year_month_weekday_last::ok -
std::chrono::year_month_weekday_last::ok
constexpr bool ok() const noexcept; (since C++20)
Checks if this object represents a valid date. Since a
year_month_weekday_last
represents the last weekday of a particular month, it is valid as long as the
year,
month and weekday are valid.
year().ok() && month().ok() && weekday().ok()
// Run this code
#include <iostream>
#include <chrono>
using namespace std::chrono;
int main()
{
std::cout << std::boolalpha;
auto ymwdl {Tuesday[last]/11/2020};
std::cout << (ymwdl.ok()) << ' ';
ymwdl = Tuesday[last]/-2/2021;
std::cout << (ymwdl.ok()) << ' ';
ymwdl += months(0); // Normalize month
std::cout << (ymwdl.ok()) << '\n';
}