std::chrono::operator==,<=>(std::chrono::year_month_day)
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std::chrono::year_month_day
Member functions
Nonmember functions
operator==operator<=>
Helper classes
Defined in header
<chrono>
constexpr bool operator==( const std::chrono::year_month_day & x,
const std::chrono::year_month_day & y ) noexcept;
(1)
(since C++20)
const std::chrono::year_month_day & y ) noexcept;
constexpr std::strong_ordering
(2)
(since C++20)
operator<=>( const std::chrono::year_month_day & x,
Compares the two year_month_day values x and y. This is a lexicographical comparison: the year() is compared first, then month(), then day().
The <, <=, >, >=, and != operators are synthesized from operator<=> and operator== respectively.
[edit] Return value
1) x.year() == y.year() && x.month() == y.month() && x.day() == y.day()
2) If x.year() <=> y.year != 0, x.year() <=> y.year; otherwise if x.month() <=> y.month() != 0, x.month() <=> y.month(); otherwise x.day() <=> y.day().
[edit] Notes
If both x and y represent valid dates (x.ok() && y.ok() == true), the result of the lexicographical comparison is consistent with the calendar order.
[edit] Example
Run this code
#include <chrono> int main() { constexpr auto ymd1{std::chrono::day (13)/7/1337}; constexpr auto ymd2{std::chrono::year (1337)/7/13}; static_assert(ymd1 == ymd2); static_assert(ymd1 <= ymd2); static_assert(ymd1 >= ymd2); static_assert(ymd1 <=> ymd2 == 0); }