libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp

   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 // weak_ptr
  12
  13 // weak_ptr& operator=(const weak_ptr& r);
  14
  15 #include <memory>
  16 #include <type_traits>
  17 #include <cassert>
  18 #include <utility>
  19
  20 #include "test_macros.h"
  21
  22 struct B
  23 {
  24     static int count;
  25
  26     B() {++count;}
  27     B(const B&) {++count;}
  28     virtual ~B() {--count;}
  29 };
  30
  31 int B::count = 0;
  32
  33 struct A
  34     : public B
  35 {
  36     static int count;
  37
  38     A() {++count;}
  39     A(const A& other) : B(other) {++count;}
  40     ~A() {--count;}
  41 };
  42
  43 int A::count = 0;
  44
  45 int main(int, char**)
  46 {
  47     {
  48         const std::shared_ptr<A> ps(new A);
  49         const std::weak_ptr<A> pA(ps);
  50         {
  51             std::weak_ptr<A> pB;
  52             pB = pA;
  53             assert(B::count == 1);
  54             assert(A::count == 1);
  55             assert(pB.use_count() == 1);
  56             assert(pA.use_count() == 1);
  57         }
  58         assert(pA.use_count() == 1);
  59         assert(B::count == 1);
  60         assert(A::count == 1);
  61     }
  62     assert(B::count == 0);
  63     assert(A::count == 0);
  64
  65     {
  66         const std::shared_ptr<A> ps(new A);
  67         std::weak_ptr<A> pA(ps);
  68         {
  69             std::weak_ptr<A> pB;
  70             pB = std::move(pA);
  71             assert(B::count == 1);
  72             assert(A::count == 1);
  73             assert(pB.use_count() == 1);
  74         }
  75         assert(B::count == 1);
  76         assert(A::count == 1);
  77     }
  78     assert(B::count == 0);
  79     assert(A::count == 0);
  80
  81   return 0;
  82 }