difference_type.pass.cpp revision 47761071be811e5815311294b71ad6ac9414963e 
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 Alloc>
13// struct allocator_traits
14// {
15//     typedef Alloc::difference_type
16//           | pointer_traits<pointer>::difference_type         difference_type;
17//     ...
18// };
19
20#include <memory>
21#include <type_traits>
22
23template <class T>
24struct A
25{
26    typedef T value_type;
27    typedef short difference_type;
28};
29
30template <class T>
31struct B
32{
33    typedef T value_type;
34};
35
36template <class T>
37struct C
38{
39    typedef T value_type;
40    struct pointer {};
41    struct const_pointer {};
42    struct void_pointer {};
43    struct const_void_pointer {};
44};
45
46namespace std
47{
48
49template <>
50struct pointer_traits<C<char>::pointer>
51{
52    typedef signed char difference_type;
53};
54
55}
56
57int main()
58{
59    static_assert((std::is_same<std::allocator_traits<A<char> >::difference_type, short>::value), "");
60    static_assert((std::is_same<std::allocator_traits<B<char> >::difference_type, std::ptrdiff_t>::value), "");
61    static_assert((std::is_same<std::allocator_traits<C<char> >::difference_type, signed char>::value), "");
62}
63