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 // shared_ptr
13 
14 // template<class T, class U> shared_ptr<T> const_pointer_cast(const shared_ptr<U>& r);
15 
16 #include <memory>
17 #include <type_traits>
18 #include <cassert>
19 
20 struct B
21 {
22     static int count;
23 
24     B() {++count;}
25     B(const B&) {++count;}
26     virtual ~B() {--count;}
27 };
28 
29 int B::count = 0;
30 
31 struct A
32     : public B
33 {
34     static int count;
35 
36     A() {++count;}
37     A(const A&) {++count;}
38     ~A() {--count;}
39 };
40 
41 int A::count = 0;
42 
43 int main()
44 {
45     {
46         const std::shared_ptr<const A> pA(new A);
47         std::shared_ptr<A> pB = std::const_pointer_cast<A>(pA);
48         assert(pB.get() == pA.get());
49         assert(!pB.owner_before(pA) && !pA.owner_before(pB));
50     }
51     {
52         const std::shared_ptr<const A> pA;
53         std::shared_ptr<A> pB = std::const_pointer_cast<A>(pA);
54         assert(pB.get() == pA.get());
55         assert(!pB.owner_before(pA) && !pA.owner_before(pB));
56     }
57 }
58