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 10#ifndef _LIBCPP___FUNCTIONAL_INVOKE_H 11#define _LIBCPP___FUNCTIONAL_INVOKE_H 12 13#include <__config> 14#include <__type_traits/invoke.h> 15#include <__utility/forward.h> 16 17#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 18# pragma GCC system_header 19#endif 20 21_LIBCPP_BEGIN_NAMESPACE_STD 22 23#if _LIBCPP_STD_VER >= 17 24 25template <class _Fn, class... _Args> 26_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 invoke_result_t<_Fn, _Args...> 27invoke(_Fn&& __f, _Args&&... __args) noexcept(is_nothrow_invocable_v<_Fn, _Args...>) { 28 return std::__invoke(std::forward<_Fn>(__f), std::forward<_Args>(__args)...); 29} 30 31#endif // _LIBCPP_STD_VER >= 17 32 33#if _LIBCPP_STD_VER >= 23 34template <class _Result, class _Fn, class... _Args> 35 requires is_invocable_r_v<_Result, _Fn, _Args...> 36_LIBCPP_HIDE_FROM_ABI constexpr _Result 37invoke_r(_Fn&& __f, _Args&&... __args) noexcept(is_nothrow_invocable_r_v<_Result, _Fn, _Args...>) { 38 if constexpr (is_void_v<_Result>) { 39 static_cast<void>(std::invoke(std::forward<_Fn>(__f), std::forward<_Args>(__args)...)); 40 } else { 41 // TODO: Use reference_converts_from_temporary_v once implemented 42 // using _ImplicitInvokeResult = invoke_result_t<_Fn, _Args...>; 43 // static_assert(!reference_converts_from_temporary_v<_Result, _ImplicitInvokeResult>, 44 static_assert(true, 45 "Returning from invoke_r would bind a temporary object to the reference return type, " 46 "which would result in a dangling reference."); 47 return std::invoke(std::forward<_Fn>(__f), std::forward<_Args>(__args)...); 48 } 49} 50#endif 51 52_LIBCPP_END_NAMESPACE_STD 53 54#endif // _LIBCPP___FUNCTIONAL_INVOKE_H 55