# std::chrono::zoned_time

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< cpp‎ | chrono

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 `TimeZonePtr`s are allowed but difficult to use, as the `zoned_time` will be immovable and it is not possible to access the stored `TimeZonePtr`.

### Member types

Member type | Definition
`duration` | std::common_type_t<Duration, std::chrono::seconds>

### Member functions

(constructor) | constructs a `zoned_time` (public member function)
operator= | assigns value to a `zoned_time` (public member function)
get_time_zone | obtains a copy of the time zone pointer (public member function)
operator local_time get_local_time | obtains the stored time point as a `local_time` (public member function)
operator sys_time get_sys_time | obtains the stored time point as a `sys_time` (public member function)
get_info | obtain information about the time zone at the stored time point (public member function)

### Non-member functions

operator== (C++20) | compares two `zoned_time` values (function template)
operator<< (C++20) | outputs a `zoned_time` into a stream (function template)

### Helper classes

std::formatter<std::chrono::zoned_time> (C++20) | formatting support for `zoned_time` (class template specialization)

### Deduction guides

### Example

Run this code

    #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

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