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___TYPE_TRAITS_IS_CALLABLE_H 10#define _LIBCPP___TYPE_TRAITS_IS_CALLABLE_H 11 12#include <__config> 13#include <__type_traits/integral_constant.h> 14#include <__utility/declval.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 22template <class _Func, class... _Args, class = decltype(std::declval<_Func>()(std::declval<_Args>()...))> 23true_type __is_callable_helper(int); 24template <class...> 25false_type __is_callable_helper(...); 26 27template <class _Func, class... _Args> 28struct __is_callable : decltype(std::__is_callable_helper<_Func, _Args...>(0)) {}; 29 30_LIBCPP_END_NAMESPACE_STD 31 32#endif // _LIBCPP___TYPE_TRAITS_IS_CALLABLE_H 33