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 22 template <class _Func, class... _Args, class = decltype(std::declval<_Func>()(std::declval<_Args>()...))> 23 true_type __is_callable_helper(int); 24 template <class...> 25 false_type __is_callable_helper(...); 26 27 template <class _Func, class... _Args> 28 struct __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