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_INVOCABLE_H 10 #define _LIBCPP___CONCEPTS_INVOCABLE_H 11 12 #include <__config> 13 #include <__functional/invoke.h> 14 #include <__utility/forward.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.invocable] 25 26 template <class _Fn, class... _Args> 27 concept invocable = requires(_Fn&& __fn, _Args&&... __args) { 28 std::invoke(std::forward<_Fn>(__fn), std::forward<_Args>(__args)...); // not required to be equality preserving 29 }; 30 31 // [concept.regular.invocable] 32 33 template <class _Fn, class... _Args> 34 concept regular_invocable = invocable<_Fn, _Args...>; 35 36 #endif // _LIBCPP_STD_VER >= 20 37 38 _LIBCPP_END_NAMESPACE_STD 39 40 #endif // _LIBCPP___CONCEPTS_INVOCABLE_H 41