2 //===----------------------------------------------------------------------===//
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
8 //===----------------------------------------------------------------------===//
10 #ifndef _LIBCPP___RANGES_ENABLE_VIEW_H
11 #define _LIBCPP___RANGES_ENABLE_VIEW_H
16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17 #pragma GCC system_header
21 #include <__undef_macros>
23 _LIBCPP_BEGIN_NAMESPACE_STD
25 #if !defined(_LIBCPP_HAS_NO_RANGES)
32 inline constexpr bool enable_view = derived_from<_Tp, view_base>;
34 } // end namespace ranges
36 #endif // !_LIBCPP_HAS_NO_RANGES
38 _LIBCPP_END_NAMESPACE_STD
42 #endif // _LIBCPP___RANGES_ENABLE_VIEW_H