1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
11#define _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
12
13#include <__config>
14#include <__type_traits/void_t.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#if _LIBCPP_STD_VER >= 14
23
24template <class _Tp, class _Key = void, class = void>
25inline const bool __is_transparent_v = false;
26
27template <class _Tp, class _Key>
28inline const bool __is_transparent_v<_Tp, _Key, __void_t<typename _Tp::is_transparent> > = true;
29
30#endif
31
32// Two types are considered transparently comparable if `comparator(key, arg)` is equivalent to `comparator(key,
33// <implicit cast to KeyT>(arg))`.
34//
35// This is different from `__is_transparent_v`, which is only a property of the comparator and doesn't provide
36// additional semantic guarantees.
37template <class _Comparator, class _KeyT, class _Arg, class = void>
38inline const bool __is_transparently_comparable_v = false;
39
40_LIBCPP_END_NAMESPACE_STD
41
42#endif // _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
43