libstdc++-v3/testsuite/23_containers/unordered_map/cons/56112.cc

   1 // { dg-do run { target c++11 } }
   2
   3 // Copyright (C) 2013-2025 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20 #include <unordered_map>
  21 #include <utility>
  22
  23 #include <testsuite_hooks.h>
  24
  25 struct Key
  26 {
  27   explicit Key(const int* p) : value(p) { }
  28   ~Key() { value = nullptr; }
  29
  30   bool operator==(const Key& k) const
  31   { return *value == *k.value; }
  32
  33   const int* value;
  34 };
  35
  36 struct hash
  37 {
  38   std::size_t operator()(const Key& k) const noexcept
  39   { return *k.value; }
  40 };
  41
  42 struct S
  43 {
  44   static int _count;
  45
  46   int value;
  47   operator std::pair<const Key, int>() const
  48   {
  49     ++_count;
  50     return { Key(&value), value };
  51   }
  52 };
  53
  54 int S::_count = 0;
  55
  56 void test01()
  57 {
  58     S s[1] = { {2} };
  59     std::unordered_map<Key, int, hash> m(s, s + 1);
  60     VERIFY( S::_count == 1 );
  61
  62     std::unordered_multimap<Key, int, hash> mm(s, s + 1);
  63     VERIFY( S::_count == 2 );
  64 }
  65
  66 int main()
  67 {
  68   test01();
  69   return 0;
  70 }