libs/interprocess/example/doc_unordered_map.cpp

   1 //////////////////////////////////////////////////////////////////////////////
   2 //
   3 // (C) Copyright Ion Gaztanaga 2006-2009. Distributed under the Boost
   4 // Software License, Version 1.0. (See accompanying file
   5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // See http://www.boost.org/libs/interprocess for documentation.
   8 //
   9 //////////////////////////////////////////////////////////////////////////////
  10 #include <boost/interprocess/detail/config_begin.hpp>
  11 #include <boost/interprocess/detail/workaround.hpp>
  12 //[doc_unordered_map
  13 #include <boost/interprocess/managed_shared_memory.hpp>
  14 #include <boost/interprocess/allocators/allocator.hpp>
  15
  16 #include <boost/unordered_map.hpp>     //boost::unordered_map
  17 #include <functional>                  //std::equal_to
  18 #include <boost/functional/hash.hpp>   //boost::hash
  19 //<-
  20 #include "../test/get_process_id_name.hpp"
  21 //->
  22
  23 int main ()
  24 {
  25    using namespace boost::interprocess;
  26    //Remove shared memory on construction and destruction
  27    struct shm_remove
  28    {
  29    //<-
  30    #if 1
  31       shm_remove() { shared_memory_object::remove(test::get_process_id_name()); }
  32       ~shm_remove(){ shared_memory_object::remove(test::get_process_id_name()); }
  33    #else
  34    //->
  35       shm_remove() { shared_memory_object::remove("MySharedMemory"); }
  36       ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
  37    //<-
  38    #endif
  39    //->
  40    } remover;
  41
  42    //Create shared memory
  43    //<-
  44    #if 1
  45    managed_shared_memory segment(create_only, test::get_process_id_name(), 65536);
  46    #else
  47    //->
  48    managed_shared_memory segment(create_only, "MySharedMemory", 65536);
  49    //<-
  50    #endif
  51    //->
  52
  53    //Note that unordered_map<Key, MappedType>'s value_type is std::pair<const Key, MappedType>,
  54    //so the allocator must allocate that pair.
  55    typedef int    KeyType;
  56    typedef float  MappedType;
  57    typedef std::pair<const int, float> ValueType;
  58
  59    //Typedef the allocator
  60    typedef allocator<ValueType, managed_shared_memory::segment_manager> ShmemAllocator;
  61
  62    //Alias an unordered_map of ints that uses the previous STL-like allocator.
  63    typedef boost::unordered_map
  64       < KeyType               , MappedType
  65       , boost::hash<KeyType>  ,std::equal_to<KeyType>
  66       , ShmemAllocator>
  67    MyHashMap;
  68
  69    //Construct a shared memory hash map.
  70    //Note that the first parameter is the initial bucket count and
  71    //after that, the hash function, the equality function and the allocator
  72    MyHashMap *myhashmap = segment.construct<MyHashMap>("MyHashMap")  //object name
  73       ( 3, boost::hash<int>(), std::equal_to<int>()                  //
  74       , segment.get_allocator<ValueType>());                         //allocator instance
  75
  76    //Insert data in the hash map
  77    for(int i = 0; i < 100; ++i){
  78       myhashmap->insert(ValueType(i, (float)i));
  79    }
  80    return 0;
  81 }
  82 //]
  83 #include <boost/interprocess/detail/config_end.hpp>