std::chrono::zoned_time 的推导指引

 

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std::chrono::zoned_time

成员函数

zoned_time::zoned_time

zoned_time::operator=

zoned_time::get_time_zone

zoned_time::get_sys_timezoned_time::operator sys_time

zoned_time::get_local_timezoned_time::operator local_time

zoned_time::get_info

非成员函数

operator==

operator<<

辅助类

formatter<std::chrono::zoned_time>

推导指引

 

zoned_time() -> zoned_time<std::chrono::seconds>;	(1)	(C++20 起)
template< class Duration > zoned_time(std::chrono::sys_time<Duration>)     -> zoned_time<std::common_type_t<Duration, std::chrono::seconds>>;	(2)	(C++20 起)
template< class TimeZonePtrOrName > zoned_time(TimeZonePtrOrName&&) -> zoned_time<std::chrono::seconds, /* see below */>;	(3)	(C++20 起)
template< class TimeZonePtrOrName, class Duration > zoned_time(TimeZonePtrOrName&&, std::chrono::sys_time<Duration>)     -> zoned_time<std::common_type_t<Duration, std::chrono::seconds>, /* see below */>;	(4)	(C++20 起)
template< class TimeZonePtrOrName, class Duration > zoned_time(TimeZonePtrOrName&&, std::chrono::local_time<Duration>,            std::chrono::choose = std::chrono::choose::earliest)     -> zoned_time<std::common_type_t<Duration, std::chrono::seconds>, /* see below */>;	(5)	(C++20 起)
template< class TimeZonePtrOrName&&, class Duration, class TimeZonePtr2 > zoned_time(TimeZonePtrOrName, std::chrono::zoned_time<Duration, TimeZonePtr2>,            std::chrono::choose = std::chrono::choose::earliest)     -> zoned_time<std::common_type_t<Duration, std::chrono::seconds>, /* see below */>;	(6)	(C++20 起)

为 zoned_time 提供六个推导指引。它们把 Duration 正规化为最小解析为 std::chrono::seconds ，并提供用可转换成 std::string_view 的类型指定时区名的正确处理。

3-6) 若 std::is_convertible_v<TimeZonePtrOrName, std::string_view> 为 true ，则推导的第二模板实参为 const std::chrono::time_zone* 。否则为 std::remove_cvref_t<TimeZonePtrOrName> 。