std::chrono::zoned_time<Duration,TimeZonePtr>::zoned_time

 

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chrono I/O
parse (C++20)
C-style date and time

 

std::chrono::zoned_time

Member functions

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

Nonmember functions

operator==

operator<<

Helper classes

formatter<std::chrono::zoned_time>

hash<std::chrono::zoned_time> (C++26)

Deduction guides

 

zoned_time();	(1)	(since C++20)
zoned_time( const std::chrono::sys_time<Duration>& st );	(2)	(since C++20)
zoned_time( const zoned_time& other ) = default;	(3)	(since C++20)
template< class Duration2 > zoned_time( const std::chrono::zoned_time<Duration2, TimeZonePtr>& other );	(4)	(since C++20)
explicit zoned_time( TimeZonePtr z );	(5)	(since C++20)
explicit zoned_time( std::string_view name );	(6)	(since C++20)
zoned_time( TimeZonePtr z, const std::chrono::sys_time<Duration>& st );	(7)	(since C++20)
zoned_time( std::string_view name, const std::chrono::sys_time<Duration>& st );	(8)	(since C++20)
zoned_time( TimeZonePtr z, const std::chrono::local_time<Duration>& tp );	(9)	(since C++20)
zoned_time( std::string_view name, const std::chrono::local_time<Duration>& tp );	(10)	(since C++20)
zoned_time( TimeZonePtr z, const std::chrono::local_time<Duration>& tp,             std::chrono::choose c );	(11)	(since C++20)
zoned_time( std::string_view name,             const std::chrono::local_time<Duration>& tp, std::chrono::choose c );	(12)	(since C++20)
template< class Duration2, class TimeZonePtr2 > zoned_time( TimeZonePtr z,             const std::chrono::zoned_time<Duration2, TimeZonePtr2>& zt );	(13)	(since C++20)
template< class Duration2, class TimeZonePtr2 > zoned_time( TimeZonePtr z,             const std::chrono::zoned_time<Duration2, TimeZonePtr2>& zt,             std::chrono::choose );	(14)	(since C++20)
template< class Duration2, class TimeZonePtr2 > zoned_time( std::string_view name,             const std::chrono::zoned_time<Duration2, TimeZonePtr2>& zt );	(15)	(since C++20)
template< class Duration2, class TimeZonePtr2 > zoned_time( std::string_view name,             const std::chrono::zoned_time<Duration2, TimeZonePtr2>& zt,             std::chrono::choose );	(16)	(since C++20)

Constructs a zoned_time object, initializing the stored time zone pointer and time point according to the following table, where traits is std::chrono::zoned_traits<TimeZonePtr>:

Overload	Time zone pointer (denoted zone)	Time point (a std::chrono::sys_time<duration>)	Notes
(1)	traits::default_zone()	default constructed	(a)
(2)		st
(3)	other.get_time_zone()	other.get_sys_time()	(b)
(4)	other.get_time_zone()	other.get_sys_time()	(e)
(5)	std::move(z)	default constructed
(6)	traits::locate_zone(name)		(c)
(7)	std::move(z)	st
(8)	traits::locate_zone(name)		(c)
(9)	std::move(z)	zone->to_sys(tp)	(d)
(10)	traits::locate_zone(name)		(c,d)
(11)	std::move(z)	zone->to_sys(tp, c)	(d)
(12)	traits::locate_zone(name)		(c,d)
(13,14)	std::move(z)	zt.get_sys_time()	(e)
(15,16)	traits::locate_zone(name)		(c,e)

a) Constructors specified to call traits::default_zone() (1,2) do not participate in overload resolution if that expression is not well-formed.

b) The defaulted copy constructor (3) is defined as deleted if std::is_copy_constructible_v<TimeZonePtr> is false.

c) Constructors with a std::string_view parameter name (6,8,10,12,15,16) do not participate in overload resolution if traits::locate_zone(name) is not well-formed or if that expression is not convertible to TimeZonePtr.

d) Constructors specified to call zone->to_sys (9-12) do not participate in overload resolution if that call expression is not well-formed or if the result is not convertible to std::chrono::sys_time<duration>.

e) Constructors with a template parameter Duration2 (4,13-16) do not participate in overload resolution if Duration2 is not convertible to Duration.

The behavior is undefined if the time zone pointer (initialized as described above) does not refer to a time zone.

Notes

zoned_time does not have a move constructor and attempting to move one will perform a copy instead using the defaulted copy constructor (3). Thus, when TimeZonePtr is a move-only type, zoned_time is immovable: it can be neither moved nor copied.

The constructors (14,16) accept a std::chrono::choose parameter, but that parameter has no effect.

Example

Run this code

#include <chrono>
#include <iostream>
#include <string_view>
 
int main()
{
    using std::chrono_literals::operator""y;
    using std::operator""sv;
 
    std::cout << std::chrono::zoned_time{} << " : default\n";
 
    constexpr std::string_view location1{"America/Phoenix"sv};
    std::cout << std::chrono::zoned_time{location1} << " : " << location1 << '\n';
 
    const std::chrono::time_zone* timeZonePtr = std::chrono::locate_zone("UTC");
    std::cout << std::chrono::zoned_time{timeZonePtr} << " : UTC time zone\n";
 
    constexpr auto location2{"Europe/Rome"sv};
    std::cout << std::chrono::zoned_time{location2, std::chrono::local_days{2021y/12/31}}
              << " : " << location2 << '\n';
 
    constexpr auto location3{"Europe/Rome"sv};
    constexpr auto some_date = std::chrono::sys_time<std::chrono::days>{2021y/12/31};
    std::cout << std::chrono::zoned_time{location3, some_date}
              << " : " << location3 << '\n';
 
    const auto now =
        std::chrono::floor<std::chrono::minutes>(std::chrono::system_clock::now());
    constexpr auto location4{"Europe/Rome"sv};
    std::cout << std::chrono::zoned_time{location4, now} << " : " << location4 << '\n';
 
    constexpr auto NewYork{"America/New_York"sv};
    constexpr auto Tokyo{"Asia/Tokyo"sv};
    const std::chrono::zoned_time tz_Tokyo{Tokyo, now};
    const std::chrono::zoned_time tz_NewYork{NewYork, now};
    std::cout << std::chrono::zoned_time{Tokyo, tz_NewYork} << " : " << Tokyo << '\n';
    std::cout << std::chrono::zoned_time{NewYork, tz_Tokyo} << " : " << NewYork << '\n';
}

Possible output:

1970-01-01 00:00:00 UTC : default
1969-12-31 17:00:00 MST : America/Phoenix
1970-01-01 00:00:00 UTC : UTC time zone
2021-12-31 00:00:00 CET : Europe/Rome
2021-12-31 01:00:00 CET : Europe/Rome
2021-09-20 23:04:00 CEST : Europe/Rome
2021-09-21 06:04:00 JST : Asia/Tokyo
2021-09-20 17:04:00 EDT : America/New_York