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_ENABLE_IF_H 10 #define _LIBCPP___TYPE_TRAITS_ENABLE_IF_H 11 12 #include <__config> 13 14 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 15 # pragma GCC system_header 16 #endif 17 18 _LIBCPP_BEGIN_NAMESPACE_STD 19 20 template <bool, class _Tp = void> 21 struct _LIBCPP_TEMPLATE_VIS enable_if {}; 22 template <class _Tp> 23 struct _LIBCPP_TEMPLATE_VIS enable_if<true, _Tp> { 24 typedef _Tp type; 25 }; 26 27 template <bool _Bp, class _Tp = void> 28 using __enable_if_t _LIBCPP_NODEBUG = typename enable_if<_Bp, _Tp>::type; 29 30 #if _LIBCPP_STD_VER >= 14 31 template <bool _Bp, class _Tp = void> 32 using enable_if_t = typename enable_if<_Bp, _Tp>::type; 33 #endif 34 35 _LIBCPP_END_NAMESPACE_STD 36 37 #endif // _LIBCPP___TYPE_TRAITS_ENABLE_IF_H 38