std::chrono::year_month_day_last::ok (3) - Linux Manuals
std::chrono::year_month_day_last::ok: std::chrono::year_month_day_last::ok
NAME
std::chrono::year_month_day_last::ok - std::chrono::year_month_day_last::ok
Synopsis
constexpr bool ok() const noexcept; (since C++20)
Checks if *this represents a valid date. Because a year_month_day_last represents the last day of a particular month, it represents a valid date as long as the year and month are valid.
Return value
year().ok() && month().ok()