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- // -*- C++ -*-
- //===----------------------------------------------------------------------===//
- //
- // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- // See https://llvm.org/LICENSE.txt for license information.
- // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- //
- //===----------------------------------------------------------------------===//
- #ifndef _LIBCPP___FUNCTIONAL_INVOKE_H
- #define _LIBCPP___FUNCTIONAL_INVOKE_H
- #include <__config>
- #include <__type_traits/invoke.h>
- #include <__utility/forward.h>
- #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
- # pragma GCC system_header
- #endif
- _LIBCPP_BEGIN_NAMESPACE_STD
- #if _LIBCPP_STD_VER >= 17
- template <class _Fn, class ..._Args>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 invoke_result_t<_Fn, _Args...>
- invoke(_Fn&& __f, _Args&&... __args)
- noexcept(is_nothrow_invocable_v<_Fn, _Args...>)
- {
- return _VSTD::__invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...);
- }
- #endif // _LIBCPP_STD_VER >= 17
- #if _LIBCPP_STD_VER >= 23
- template <class _Result, class _Fn, class... _Args>
- requires is_invocable_r_v<_Result, _Fn, _Args...>
- _LIBCPP_HIDE_FROM_ABI constexpr _Result
- invoke_r(_Fn&& __f, _Args&&... __args) noexcept(is_nothrow_invocable_r_v<_Result, _Fn, _Args...>) {
- if constexpr (is_void_v<_Result>) {
- static_cast<void>(std::invoke(std::forward<_Fn>(__f), std::forward<_Args>(__args)...));
- } else {
- // TODO: Use reference_converts_from_temporary_v once implemented
- // using _ImplicitInvokeResult = invoke_result_t<_Fn, _Args...>;
- // static_assert(!reference_converts_from_temporary_v<_Result, _ImplicitInvokeResult>,
- static_assert(true,
- "Returning from invoke_r would bind a temporary object to the reference return type, "
- "which would result in a dangling reference.");
- return std::invoke(std::forward<_Fn>(__f), std::forward<_Args>(__args)...);
- }
- }
- #endif
- _LIBCPP_END_NAMESPACE_STD
- #endif // _LIBCPP___FUNCTIONAL_INVOKE_H
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