is_transparent.h 989 B

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  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. #ifndef _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
  10. #define _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
  11. #include <__config>
  12. #include <type_traits>
  13. #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  14. # pragma GCC system_header
  15. #endif
  16. _LIBCPP_BEGIN_NAMESPACE_STD
  17. #if _LIBCPP_STD_VER > 11
  18. template <class _Tp, class, class = void>
  19. struct __is_transparent : false_type {};
  20. template <class _Tp, class _Up>
  21. struct __is_transparent<_Tp, _Up,
  22. typename __void_t<typename _Tp::is_transparent>::type>
  23. : true_type {};
  24. #endif
  25. _LIBCPP_END_NAMESPACE_STD
  26. #endif // _LIBCPP___FUNCTIONAL_IS_TRANSPARENT