doc_unordered_map.cpp

//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2006-2012. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////

#include <boost/interprocess/detail/workaround.hpp>
#if BOOST_CXX_VERSION >=201103L

//[doc_unordered_map
#include <boost/interprocess/managed_shared_memory.hpp>
#include <boost/interprocess/allocators/allocator.hpp>

//<-
//Shield against external warnings
#include <boost/interprocess/detail/config_external_begin.hpp>
//->

#include <boost/unordered_map.hpp>     //boost::unordered_map

//<-
#include <boost/interprocess/detail/config_external_end.hpp>
#include "../test/get_process_id_name.hpp"
//->

#include <functional>                  //std::equal_to
#include <boost/container_hash/hash.hpp>   //boost::hash

//<-
#include "../test/get_process_id_name.hpp"
//->

int main ()
{
   using namespace boost::interprocess;
   //Remove shared memory on construction and destruction
   struct shm_remove
   {
      shm_remove() { shared_memory_object::remove(test::get_process_id_name()); }
      ~shm_remove(){ shared_memory_object::remove(test::get_process_id_name()); }
   } remover;
   //<-
   (void)remover;
   //->

   //Create shared memory
   managed_shared_memory segment(create_only, test::get_process_id_name(), 65536);

   //Note that unordered_map<Key, MappedType>'s value_type is std::pair<const Key, MappedType>,
   //so the allocator must allocate that pair.
   typedef int    KeyType;
   typedef float  MappedType;
   typedef std::pair<const int, float> ValueType;

   //Typedef the allocator
   typedef allocator<ValueType, managed_shared_memory::segment_manager> ShmemAllocator;

   //Alias an unordered_map of ints that uses the previous STL-like allocator.
   typedef boost::unordered_map
      < KeyType               , MappedType
      , boost::hash<KeyType>  ,std::equal_to<KeyType>
      , ShmemAllocator>
   MyHashMap;

   //Construct a shared memory hash map.
   //Note that the first parameter is the initial bucket count and
   //after that, the hash function, the equality function and the allocator
   MyHashMap *myhashmap = segment.construct<MyHashMap>("MyHashMap")  //object name
      ( 3u, boost::hash<int>(), std::equal_to<int>()                  //
      , segment.get_allocator<ValueType>());                         //allocator instance

   //Insert data in the hash map
   for(std::size_t i = 0; i < 100u; ++i){
      myhashmap->insert(ValueType((int)i, (float)i));
   }
   return 0;
}
//]
#else
int main()
{
   return 0;
}
#endif //#if BOOST_CXX_VERSION >=201103L