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
26template <class _Fn, class... _Args>
27concept 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
33template <class _Fn, class... _Args>
34concept 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