# std::chrono::operator==,<,<=,>,>=,<=>(std::chrono::leap_second)

< cpp‎ | chrono‎ | leap second

定义于头文件 `<chrono>` |  |
constexpr bool operator==( const std::chrono::leap_second& x, const std::chrono::leap_second& y ) noexcept; | (1) | (C++20 起)
constexpr std::strong_ordering operator<=>( const std::chrono::leap_second& x, const std::chrono::leap_second& y ) noexcept; | (2) | (C++20 起)
template< class Duration > constexpr bool operator==( const std::chrono::leap_second& x, const std::chrono::sys_time<Duration>& y ) noexcept; | (3) | (C++20 起)
template< class Duration > constexpr bool operator< ( const std::chrono::leap_second& x, const std::chrono::sys_time<Duration>& y ) noexcept; | (4) | (C++20 起)
template< class Duration > constexpr bool operator< ( const std::chrono::sys_time<Duration>& x, const std::chrono::leap_second& y ) noexcept; | (5) | (C++20 起)
template< class Duration > constexpr bool operator> ( const std::chrono::leap_second& x, const std::chrono::sys_time<Duration>& y ) noexcept; | (6) | (C++20 起)
template< class Duration > constexpr bool operator> ( const std::chrono::sys_time<Duration>& x, const std::chrono::leap_second& y ) noexcept; | (7) | (C++20 起)
template< class Duration > constexpr bool operator<=( const std::chrono::leap_second& x, const std::chrono::sys_time<Duration>& y ) noexcept; | (8) | (C++20 起)
template< class Duration > constexpr bool operator<=( const std::chrono::sys_time<Duration>& x, const std::chrono::leap_second& y ) noexcept; | (9) | (C++20 起)
template< class Duration > constexpr bool operator>=( const std::chrono::leap& x, const std::chrono::sys_time<Duration>& y ) noexcept; | (10) | (C++20 起)
template< class Duration > constexpr bool operator>=( const std::chrono::sys_time<Duration>& x, const std::chrono::leap_second& y ) noexcept; | (11) | (C++20 起)
template< class Duration > requires std::three_way_comparable_with< std:chrono::sys_seconds, std::chrono::sys_time<Duration>> constexpr auto operator<=>( const std::chrono::leap_second& x, const std::chrono::sys_time<Duration>& y ) noexcept; | (12) | (C++20 起)

比较对象 `x` 与 `y` 所表示的日期和时间。

(12) 的返回类型从 x.date() <=> y 推导，从而为 std::chrono::seconds 与 `Duration` 的三路比较结果类型。

`!=` 运算符从 `operator==` 合成。

### 返回值

1) x.date() == y.date()
2) x.date() <=> y.date()
3) x.date() == y
4) x.date() < y
5) x < y.date()
6) x.date() > y
7) x > y.date()
8) x.date() <= y
9) x <= y.date()
10) x.date() >= y
11) x >= y.date()
12) x.date() <=> y