Defined in header <chrono> | ||
|---|---|---|
template<
class Duration,
class TimeZonePtr = const std::chrono::time_zone*
> class zoned_time;
| (since C++20) | |
using zoned_seconds = std::chrono::zoned_time<std::chrono::seconds>; | (since C++20) |
The class zoned_time represents a logical pairing of a time zone and a std::chrono::time_point whose resolution is Duration.
An invariant of zoned_time is that it always refers to a valid time zone and represents an existing and unambiguous time point in that time zone. Consistent with this invariant, zoned_time has no move constructor or move assignment operator; attempts to move a zoned_time will perform a copy.
The program is ill-formed if Duration is not a specialization of std::chrono::duration.
The template parameter TimeZonePtr allows users to supply their own time zone pointer types and further customize the behavior of zoned_time via std::chrono::zoned_traits. Custom time zone types need not support all the operations supported by std::chrono::time_zone, only those used by the functions actually called on the zoned_time.
TimeZonePtr must be MoveConstructible. Move-only TimeZonePtrs are allowed but difficult to use, as the zoned_time will be immovable and it is not possible to access the stored TimeZonePtr.
| Member type | Definition |
|---|---|
duration | std::common_type_t<Duration, std::chrono::seconds> |
constructs a zoned_time (public member function) |
|
assigns value to a zoned_time (public member function) |
|
| obtains a copy of the time zone pointer (public member function) |
|
obtains the stored time point as a local_time (public member function) |
|
obtains the stored time point as a sys_time (public member function) |
|
| obtain information about the time zone at the stored time point (public member function) |
|
(C++20) | compares two zoned_time values (function template) |
|
(C++20) | outputs a zoned_time into a stream (function template) |
|
(C++20) | formatting support for zoned_time (class template specialization) |
#include <algorithm>
#include <chrono>
#include <iomanip>
#include <iostream>
#include <stdexcept>
#include <string_view>
int main()
{
constexpr std::string_view locations[] =
{
"Africa/Casablanca", "America/Argentina/Buenos_Aires",
"America/Barbados", "America/Indiana/Petersburg",
"America/Tarasco_Bar", "Antarctica/Casey",
"Antarctica/Vostok", "Asia/Magadan",
"Asia/Manila", "Asia/Shanghai",
"Asia/Tokyo", "Atlantic/Bermuda",
"Australia/Darwin", "Europe/Isle_of_Man",
"Europe/Laputa", "Indian/Christmas",
"Indian/Cocos", "Pacific/Galapagos",
};
constexpr auto width = std::ranges::max_element(locations, {},
[](const auto& s) { return s.length(); })->length();
for (const auto location : locations)
try
{
// may throw if 'location' is not in the time zone database
const std::chrono::zoned_time zt{location, std::chrono::system_clock::now()};
std::cout << std::setw(width) << location << " - Zoned Time: " << zt << '\n';
}
catch (std::runtime_error& ex)
{
std::cout << "Error: " << ex.what() << '\n';
}
}Possible output:
Africa/Casablanca - Zoned Time: 2023-06-29 20:58:34.697449319 +01
America/Argentina/Buenos_Aires - Zoned Time: 2023-06-29 16:58:34.709957354 -03
America/Barbados - Zoned Time: 2023-06-29 15:58:34.709977888 AST
America/Indiana/Petersburg - Zoned Time: 2023-06-29 15:58:34.709998072 EDT
Error: tzdb: cannot locate zone: America/Tarasco_Bar
Antarctica/Casey - Zoned Time: 2023-06-30 06:58:34.710093685 +11
Antarctica/Vostok - Zoned Time: 2023-06-30 01:58:34.710107932 +06
Asia/Magadan - Zoned Time: 2023-06-30 06:58:34.710121831 +11
Asia/Manila - Zoned Time: 2023-06-30 03:58:34.710134751 PST
Asia/Shanghai - Zoned Time: 2023-06-30 03:58:34.710153259 CST
Asia/Tokyo - Zoned Time: 2023-06-30 04:58:34.710172815 JST
Atlantic/Bermuda - Zoned Time: 2023-06-29 16:58:34.710191043 ADT
Australia/Darwin - Zoned Time: 2023-06-30 05:28:34.710236720 ACST
Europe/Isle_of_Man - Zoned Time: 2023-06-29 20:58:34.710256834 BST
Error: tzdb: cannot locate zone: Europe/Laputa
Indian/Christmas - Zoned Time: 2023-06-30 02:58:34.710360409 +07
Indian/Cocos - Zoned Time: 2023-06-30 02:28:34.710377520 +0630
Pacific/Galapagos - Zoned Time: 2023-06-29 13:58:34.710389952 -06
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/chrono/zoned_time