1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // <memory>
11 
12 // template <class Ptr>
13 // struct pointer_traits
14 // {
15 //     typedef <details> difference_type;
16 //     ...
17 // };
18 
19 #include <memory>
20 #include <type_traits>
21 
22 struct A
23 {
24     typedef short element_type;
25     typedef char difference_type;
26 };
27 
28 struct B
29 {
30     typedef short element_type;
31 };
32 
33 template <class T>
34 struct C {};
35 
36 template <class T>
37 struct D
38 {
39     typedef char difference_type;
40 };
41 
main()42 int main()
43 {
44     static_assert((std::is_same<std::pointer_traits<A>::difference_type, char>::value), "");
45     static_assert((std::is_same<std::pointer_traits<B>::difference_type, std::ptrdiff_t>::value), "");
46     static_assert((std::is_same<std::pointer_traits<C<double> >::difference_type, std::ptrdiff_t>::value), "");
47     static_assert((std::is_same<std::pointer_traits<D<int> >::difference_type, char>::value), "");
48 }
49