std::chrono::zoned_time<Duration,TimeZonePtr>::zoned_time
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
#include <chrono>
#include <iostream>
#include <string_view>
int main()
{
using std::chrono_literals::operator""y;
using std::operator""sv;
const auto now = std::chrono::floor<std::chrono::minutes>(std::chrono::system_clock::now());
{
std::cout << std::chrono::zoned_time{} << " : default\n";
}
{
constexpr std::string_view location {"America/Phoenix"sv};
std::cout << std::chrono::zoned_time{ location } << " : " << location << '\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 location{"Europe/Rome"sv};
std::cout << std::chrono::zoned_time{ location, std::chrono::local_days{2021y/12/31} }
<< " : " << location << '\n';
}
{
constexpr auto location {"Europe/Rome"sv};
constexpr auto some_date = std::chrono::sys_time<std::chrono::days>{2021y/12/31};
std::cout << std::chrono::zoned_time{ location, some_date } << " : " << location << '\n';
}
{
constexpr auto location {"Europe/Rome"sv};
std::cout << std::chrono::zoned_time{ location, now } << " : " << location << '\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
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