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> 14 15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 16 # pragma GCC system_header 17 #endif 18 19 _LIBCPP_BEGIN_NAMESPACE_STD 20 21 #if _LIBCPP_STD_VER > 17 22 23 // [concept.derived] 24 25 template<class _Dp, class _Bp> 26 concept derived_from = 27 is_base_of_v<_Bp, _Dp> && 28 is_convertible_v<const volatile _Dp*, const volatile _Bp*>; 29 30 #endif // _LIBCPP_STD_VER > 17 31 32 _LIBCPP_END_NAMESPACE_STD 33 34 #endif // _LIBCPP___CONCEPTS_DERIVED_FROM_H 35