std::chrono::zoned_time

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Time zone
(C++20)
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(C++20)(C++20)(C++20)(C++20)  
(C++20)
(C++20)
zoned_time
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)

chrono I/O
(C++20)
C-style date and time
 
std::chrono::zoned_time
 
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 types

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

Member functions

 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)

Non-member functions

(C++20)
 compares two zoned_time values
(function template)
(C++20)
 outputs a zoned_time into a stream
(function template)

Helper classes

(C++20)
 formatting support for zoned_time
(class template specialization)
(C++26)
 hash support for std::chrono::zoned_time
(class template specialization)

Helper specializations

template< class Duration >

constexpr bool enable_nonlocking_formatter_optimization

  <chrono::zoned_time<Duration, const chrono::time_zone*>> = true;
 (since C++23)

This specialization of std::enable_nonlocking_formatter_optimization enables efficient implementation of std::print and std::println for printing a chrono::zoned_time object.

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

See also

(C++20)
 represents a time zone
(class)
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