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[libc++][TZDB] Implements zoned_traits.
Implements parts of: - P0355 Extending chrono to Calendars and Time Zones
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9 files changed

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‎libcxx/include/CMakeLists.txt

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@@ -277,6 +277,7 @@ set(files
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__chrono/year_month.h
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__chrono/year_month_day.h
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__chrono/year_month_weekday.h
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__chrono/zoned_time.h
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__compare/common_comparison_category.h
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__compare/compare_partial_order_fallback.h
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__compare/compare_strong_order_fallback.h

‎libcxx/include/__chrono/zoned_time.h

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// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// For information see https://libcxx.llvm.org/DesignDocs/TimeZone.html
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#ifndef _LIBCPP___CHRONO_ZONED_TIME_H
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#define _LIBCPP___CHRONO_ZONED_TIME_H
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#include <version>
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// Enable the contents of the header only when libc++ was built with experimental features enabled.
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#if !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB)
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# include <__chrono/time_zone.h>
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# include <__chrono/tzdb_list.h>
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# include <__config>
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# include <__fwd/string_view.h>
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# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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# endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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# if _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_TIME_ZONE_DATABASE) && !defined(_LIBCPP_HAS_NO_FILESYSTEM) && \
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!defined(_LIBCPP_HAS_NO_LOCALIZATION)
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namespace chrono {
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template <class>
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struct zoned_traits {};
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template <>
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struct zoned_traits<const time_zone*> {
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI static const time_zone* default_zone() { return chrono::locate_zone("UTC"); }
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI static const time_zone* locate_zone(string_view __name) {
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return chrono::locate_zone(__name);
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}
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};
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} // namespace chrono
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# endif // _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_TIME_ZONE_DATABASE) && !defined(_LIBCPP_HAS_NO_FILESYSTEM)
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// && !defined(_LIBCPP_HAS_NO_LOCALIZATION)
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_LIBCPP_END_NAMESPACE_STD
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#endif // !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB)
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#endif // _LIBCPP___CHRONO_ZONED_TIME_H

‎libcxx/include/chrono

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@@ -786,6 +786,9 @@ class time_zone {
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bool operator==(const time_zone& x, const time_zone& y) noexcept; // C++20
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strong_ordering operator<=>(const time_zone& x, const time_zone& y) noexcept; // C++20
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// [time.zone.zonedtraits], class template zoned_traits
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template<class T> struct zoned_traits; // C++20
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// [time.zone.leap], leap second support
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class leap_second { // C++20
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public:
@@ -959,6 +962,7 @@ constexpr chrono::year operator ""y(unsigned lo
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# include <__chrono/time_zone_link.h>
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# include <__chrono/tzdb.h>
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# include <__chrono/tzdb_list.h>
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# include <__chrono/zoned_time.h>
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# endif
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#endif

‎libcxx/include/module.modulemap

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@@ -1159,6 +1159,7 @@ module std_private_chrono_year [system] { header "__chrono/yea
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module std_private_chrono_year_month [system] { header "__chrono/year_month.h" }
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module std_private_chrono_year_month_day [system] { header "__chrono/year_month_day.h" }
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module std_private_chrono_year_month_weekday [system] { header "__chrono/year_month_weekday.h" }
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module std_private_chrono_zoned_time [system] { header "__chrono/zoned_time.h" }
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module std_private_compare_common_comparison_category [system] { header "__compare/common_comparison_category.h" }
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module std_private_compare_compare_partial_order_fallback [system] { header "__compare/compare_partial_order_fallback.h" }

‎libcxx/modules/std/chrono.inc

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@@ -227,11 +227,10 @@ export namespace std {
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using std::chrono::choose;
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using std::chrono::time_zone;
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# if 0
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// [time.zone.zonedtraits], class template zoned_traits
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using std::chrono::zoned_traits;
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# if 0
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// [time.zone.zonedtime], class template zoned_time
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using std::chrono::zoned_time;
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‎libcxx/test/libcxx/diagnostics/chrono.nodiscard.verify.cpp

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@@ -72,4 +72,10 @@ void test() {
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leap.date(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
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leap.value(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
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}
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{
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using t = std::chrono::zoned_traits<const std::chrono::time_zone*>;
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t::default_zone(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
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t::locate_zone(""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
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}
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}

‎libcxx/test/std/time/time.zone/time.zone.zonedtraits/const_time_zone_default_zone.pass.cpp

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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14, c++17
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// UNSUPPORTED: no-filesystem, no-localization, no-tzdb
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// XFAIL: libcpp-has-no-experimental-tzdb
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// XFAIL: availability-tzdb-missing
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// <chrono>
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// template<> struct zoned_traits<const time_zone*>;
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// static const time_zone* default_zone();
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#include <chrono>
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#include <cassert>
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int main(int, char**) {
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std::same_as<const std::chrono::time_zone*> decltype(auto) tz =
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std::chrono::zoned_traits<const std::chrono::time_zone*>::default_zone();
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assert(tz);
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// The time zone "UTC" can be a link, this means tz->name() can be something
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// differently. For example, "Etc/UTC". Instead validate whether same time
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// zone is returned by comparing the addresses.
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const std::chrono::time_zone* expected = std::chrono::locate_zone("UTC");
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assert(tz == expected);
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return 0;
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}

‎libcxx/test/std/time/time.zone/time.zone.zonedtraits/const_time_zone_locate_zone.pass.cpp

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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14, c++17
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// UNSUPPORTED: no-filesystem, no-localization, no-tzdb
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// XFAIL: libcpp-has-no-experimental-tzdb
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// XFAIL: availability-tzdb-missing
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// <chrono>
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// template<> struct zoned_traits<const time_zone*>;
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// static const time_zone* locate_zone(string_view name);
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#include <chrono>
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#include <cassert>
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#include <concepts>
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#include "assert_macros.h"
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static void test(std::string_view name) {
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std::same_as<const std::chrono::time_zone*> decltype(auto) tz =
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std::chrono::zoned_traits<const std::chrono::time_zone*>::locate_zone(name);
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const std::chrono::time_zone* expected = std::chrono::locate_zone(name);
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assert(tz == expected);
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}
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int main(int, char**) {
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test("UTC");
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test("Europe/Berlin");
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test("Asia/Hong_Kong");
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TEST_THROWS_TYPE(std::runtime_error,
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TEST_IGNORE_NODISCARD std::chrono::zoned_traits<const std::chrono::time_zone*>::locate_zone(
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"there_is_no_time_zone_with_this_name"));
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return 0;
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}

‎libcxx/test/std/time/time.zone/time.zone.zonedtraits/types.compile.pass.cpp

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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14, c++17
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// UNSUPPORTED: no-filesystem, no-localization, no-tzdb
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// XFAIL: libcpp-has-no-experimental-tzdb
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// XFAIL: availability-tzdb-missing
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// <chrono>
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// template<class T> struct zoned_traits {};
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//
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// A specialization for const time_zone* is provided by the implementation:
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// template<> struct zoned_traits<const time_zone*> { ... }
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#include <chrono>
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#include <type_traits>
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// This test test whether non-specialized versions exhibit the expected
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// behavior. (Note these specializations are not really useful.)
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static_assert(std::is_trivial_v<std::chrono::zoned_traits<int>>);
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static_assert(std::is_trivial_v<std::chrono::zoned_traits<float>>);
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static_assert(std::is_trivial_v<std::chrono::zoned_traits<void*>>);
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struct foo {};
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static_assert(std::is_empty_v<std::chrono::zoned_traits<foo>>);
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static_assert(std::is_trivial_v<std::chrono::zoned_traits<foo>>);

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