NAME¶

std::chrono::zoned_time - std::chrono::zoned_time

Synopsis¶

Defined in header <chrono>
template<

class Duration, (since C++20)
class TimeZonePtr = const std::chrono::time_zone*

> class zoned_time;
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¶

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 obtains the stored time point as a local_time
get_local_time (public member function)
operator sys_time obtains the stored time point as a sys_time
get_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== compares two zoned_time values
(C++20) (function template)
operator<< outputs a zoned_time into a stream
(C++20) (function template)

Helper classes¶

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

See also¶

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