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// <memory>
10
11// template <class T>
12// struct pointer_traits<T*>
13// {
14// static pointer pointer_to(<details>) noexcept; // constexpr in C++20
15// ...
16// };
17
18#include <memory>
19#include <cassert>
20#include <type_traits>
21
22#include "test_macros.h"
23
24TEST_CONSTEXPR_CXX20 bool test()
25{
26 // pointer_traits<T*>
27 {
28 int i = 0;
29 static_assert(std::is_same<decltype(std::pointer_traits<int*>::pointer_to(i)), int*>::value, "");
30 ASSERT_NOEXCEPT(std::pointer_traits<int*>::pointer_to(i));
31 assert(std::pointer_traits<int*>::pointer_to(i) == &i);
32 }
33 // pointer_traits<const T*>
34 {
35 int const i = 0;
36 static_assert(std::is_same<decltype(std::pointer_traits<const int*>::pointer_to(i)), const int*>::value, "");
37 ASSERT_NOEXCEPT(std::pointer_traits<const int*>::pointer_to(i));
38 assert(std::pointer_traits<const int*>::pointer_to(i) == &i);
39 }
40 // pointer_traits<const T*> with a non-const argument
41 {
42 int i = 0;
43 static_assert(std::is_same<decltype(std::pointer_traits<const int*>::pointer_to(i)), const int*>::value, "");
44 ASSERT_NOEXCEPT(std::pointer_traits<const int*>::pointer_to(i));
45 assert(std::pointer_traits<const int*>::pointer_to(i) == &i);
46 }
47 return true;
48}
49
50int main(int, char**)
51{
52 test();
53#if TEST_STD_VER > 17
54 static_assert(test());
55#endif
56
57 {
58 // Check that pointer_traits<void*> is still well-formed, even though it has no pointer_to.
59 static_assert(std::is_same<std::pointer_traits<void*>::element_type, void>::value, "");
60 static_assert(std::is_same<std::pointer_traits<const void*>::element_type, const void>::value, "");
61 static_assert(std::is_same<std::pointer_traits<volatile void*>::element_type, volatile void>::value, "");
62 }
63
64 return 0;
65}
66

source code of libcxx/test/std/utilities/memory/pointer.traits/ptr.pointer_to.pass.cpp