libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/swap.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 // void swap(weak_ptr& r);
  14
  15 #include <memory>
  16 #include <cassert>
  17
  18 #include "test_macros.h"
  19
  20 struct A
  21 {
  22     static int count;
  23
  24     A() {++count;}
  25     A(const A&) {++count;}
  26     ~A() {--count;}
  27 };
  28
  29 int A::count = 0;
  30
  31 int main(int, char**)
  32 {
  33     {
  34         A* ptr1 = new A;
  35         A* ptr2 = new A;
  36         std::shared_ptr<A> p1(ptr1);
  37         std::weak_ptr<A> w1(p1);
  38         {
  39             std::shared_ptr<A> p2(ptr2);
  40             std::weak_ptr<A> w2(p2);
  41             w1.swap(w2);
  42             assert(w1.use_count() == 1);
  43             assert(w1.lock().get() == ptr2);
  44             assert(w2.use_count() == 1);
  45             assert(w2.lock().get() == ptr1);
  46             assert(A::count == 2);
  47         }
  48     }
  49     assert(A::count == 0);
  50
  51   return 0;
  52 }