xref: /freebsd/contrib/llvm-project/libcxx/include/__functional/is_transparent.h (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
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/integral_constant.h>
15 #include <__type_traits/void_t.h>
16 
17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18 #  pragma GCC system_header
19 #endif
20 
21 _LIBCPP_BEGIN_NAMESPACE_STD
22 
23 #if _LIBCPP_STD_VER >= 14
24 
25 template <class _Tp, class, class = void>
26 struct __is_transparent : false_type {};
27 
28 template <class _Tp, class _Up>
29 struct __is_transparent<_Tp, _Up, __void_t<typename _Tp::is_transparent> >
30    : true_type {};
31 
32 #endif
33 
34 _LIBCPP_END_NAMESPACE_STD
35 
36 #endif // _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
37