[libcxx-commits] [libcxx] [libc++][chrono] Loads tzdata.zi in tzdb. (PR #74928)

[Louis Dionne via libcxx-commits]

================
@@ -0,0 +1,86 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// For information see https://libcxx.llvm.org/DesignDocs/TimeZone.html
+
+#ifndef _LIBCPP___CHRONO_TIME_ZONE_H
+#define _LIBCPP___CHRONO_TIME_ZONE_H
+
+#include <version>
+// Enable the contents of the header only when libc++ was built with experimental features enabled.
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_TZDB)
+
+#  include <__compare/strong_order.h>
+#  include <__config>
+#  include <__memory/unique_ptr.h>
+#  include <string_view>
+
+#  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#    pragma GCC system_header
+#  endif
+
+_LIBCPP_PUSH_MACROS
+#  include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#  if _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_TIME_ZONE_DATABASE) && !defined(_LIBCPP_HAS_NO_FILESYSTEM) &&   \
+      !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+
+namespace chrono {
+
+class _LIBCPP_AVAILABILITY_TZDB time_zone {
+  _LIBCPP_HIDE_FROM_ABI time_zone() = default;
+
+public:
+  class __impl; // public so it can be used by make_unique.
+
+  // The "constructor".
+  //
+  // The default constructor is private to avoid the constructor from being an
+  // ABI interface. Instead use an __ugly_named function as an ABI interface,
+  // since users should not depend on __ugly_names.
----------------
ldionne wrote:

```suggestion
  // The default constructor is private to avoid the constructor from being part of
  // the ABI. Instead use an __ugly_named function as an ABI interface, since that
  // gives us the ability to change it in the future.
```

https://github.com/llvm/llvm-project/pull/74928