1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___CONCEPTS_DERIVED_FROM_H 10 #define _LIBCPP___CONCEPTS_DERIVED_FROM_H 11 12 #include <__config> 13 #include <__type_traits/is_base_of.h> 14 #include <__type_traits/is_convertible.h> 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 >= 20 23 24 // [concept.derived] 25 26 template <class _Dp, class _Bp> 27 concept derived_from = is_base_of_v<_Bp, _Dp> && is_convertible_v<const volatile _Dp*, const volatile _Bp*>; 28 29 #endif // _LIBCPP_STD_VER >= 20 30 31 _LIBCPP_END_NAMESPACE_STD 32 33 #endif // _LIBCPP___CONCEPTS_DERIVED_FROM_H 34