[libcxx-commits] [libcxx] [libcxx] Implement C++20 std::chrono::is_clock, std::chrono::is_clock_v (PR #160607)

[Yuxuan Chen via libcxx-commits]

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@@ -0,0 +1,45 @@
+// -*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CHRONO_IS_CLOCK_H
+#define _LIBCPP___CHRONO_IS_CLOCK_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 20
+
+#  include <__type_traits/integral_constant.h>
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yuxuanchen1997 wrote:

The intention was that if the STD_VER was < 20, the transitive include won't happen. Maybe too pessimistic. I can reorder. 

https://github.com/llvm/llvm-project/pull/160607