libstdc++-v3/testsuite/23_containers/unordered_multimap/final_hash.cc

   1 // { dg-do compile { target c++11 } }
   2
   3 // Copyright (C) 2011-2025 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 <string>
  21 #include <unordered_map>
  22
  23 namespace
  24 {
  25   template<typename _Tp>
  26   struct final_hash final
  27   {
  28     std::size_t operator() (const _Tp&) const noexcept
  29     { return 0; }
  30   };
  31 }
  32
  33 // A non-integral type:
  34 template class std::unordered_multimap<std::string, int,
  35                                        final_hash<std::string>>;
  36
  37 // An integral type;
  38 template class std::unordered_multimap<int, int, final_hash<int>>;
  39