1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
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
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
11 #define _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
12 
13 #include <__config>
14 #include <type_traits>
15 
16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17 #pragma GCC system_header
18 #endif
19 
20 _LIBCPP_BEGIN_NAMESPACE_STD
21 
22 #if _LIBCPP_STD_VER > 11
23 
24 template <class _Tp, class, class = void>
25 struct __is_transparent : false_type {};
26 
27 template <class _Tp, class _Up>
28 struct __is_transparent<_Tp, _Up,
29                         typename __void_t<typename _Tp::is_transparent>::type>
30    : true_type {};
31 
32 #endif
33 
34 _LIBCPP_END_NAMESPACE_STD
35 
36 #endif // _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
37