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_SIGNED_H
10 #define _LIBCPP___TYPE_TRAITS_IS_SIGNED_H
11 
12 #include <__config>
13 #include <__type_traits/integral_constant.h>
14 #include <__type_traits/is_arithmetic.h>
15 #include <__type_traits/is_integral.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 __has_builtin(__is_signed)
24 
25 template <class _Tp>
26 struct _LIBCPP_TEMPLATE_VIS is_signed : _BoolConstant<__is_signed(_Tp)> {};
27 
28 #  if _LIBCPP_STD_VER >= 17
29 template <class _Tp>
30 inline constexpr bool is_signed_v = __is_signed(_Tp);
31 #  endif
32 
33 #else // __has_builtin(__is_signed)
34 
35 template <class _Tp, bool = is_integral<_Tp>::value>
36 struct __libcpp_is_signed_impl : public _BoolConstant<(_Tp(-1) < _Tp(0))> {};
37 
38 template <class _Tp>
39 struct __libcpp_is_signed_impl<_Tp, false> : public true_type {}; // floating point
40 
41 template <class _Tp, bool = is_arithmetic<_Tp>::value>
42 struct __libcpp_is_signed : public __libcpp_is_signed_impl<_Tp> {};
43 
44 template <class _Tp>
45 struct __libcpp_is_signed<_Tp, false> : public false_type {};
46 
47 template <class _Tp>
48 struct _LIBCPP_TEMPLATE_VIS is_signed : public __libcpp_is_signed<_Tp> {};
49 
50 #  if _LIBCPP_STD_VER >= 17
51 template <class _Tp>
52 inline constexpr bool is_signed_v = is_signed<_Tp>::value;
53 #  endif
54 
55 #endif // __has_builtin(__is_signed)
56 
57 _LIBCPP_END_NAMESPACE_STD
58 
59 #endif // _LIBCPP___TYPE_TRAITS_IS_SIGNED_H
60