ceph/src/boost/libs/interprocess/example/doc_managed_heap_memory.cpp

   1 //////////////////////////////////////////////////////////////////////////////
   2 //
   3 // (C) Copyright Ion Gaztanaga 2006-2012. 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
  11 #include <boost/interprocess/detail/workaround.hpp>
  12 //[doc_managed_heap_memory
  13 #include <boost/interprocess/containers/list.hpp>
  14 #include <boost/interprocess/managed_heap_memory.hpp>
  15 #include <boost/interprocess/allocators/allocator.hpp>
  16 #include <cstddef>
  17
  18 using namespace boost::interprocess;
  19 typedef list<int, allocator<int, managed_heap_memory::segment_manager> >
  20    MyList;
  21
  22 int main ()
  23 {
  24    //We will create a buffer of 1000 bytes to store a list
  25    managed_heap_memory heap_memory(1000);
  26
  27    MyList * mylist = heap_memory.construct<MyList>("MyList")
  28                         (heap_memory.get_segment_manager());
  29
  30    //Obtain handle, that identifies the list in the buffer
  31    managed_heap_memory::handle_t list_handle = heap_memory.get_handle_from_address(mylist);
  32
  33    //Fill list until there is no more memory in the buffer
  34    BOOST_TRY{
  35       while(1) {
  36          mylist->insert(mylist->begin(), 0);
  37       }
  38    }
  39    BOOST_CATCH(const bad_alloc &){
  40       //memory is full
  41    } BOOST_CATCH_END
  42    //Let's obtain the size of the list
  43    MyList::size_type old_size = mylist->size();
  44    //<-
  45    (void)old_size;
  46    //->
  47
  48    //To make the list bigger, let's increase the heap buffer
  49    //in 1000 bytes more.
  50    heap_memory.grow(1000);
  51
  52    //If memory has been reallocated, the old pointer is invalid, so
  53    //use previously obtained handle to find the new pointer.
  54    mylist = static_cast<MyList *>
  55                (heap_memory.get_address_from_handle(list_handle));
  56
  57    //Fill list until there is no more memory in the buffer
  58    BOOST_TRY{
  59       while(1) {
  60          mylist->insert(mylist->begin(), 0);
  61       }
  62    }
  63    BOOST_CATCH(const bad_alloc &){
  64       //memory is full
  65    } BOOST_CATCH_END
  66
  67    //Let's obtain the new size of the list
  68    MyList::size_type new_size = mylist->size();
  69    //<-
  70    (void)new_size;
  71    //->
  72
  73    assert(new_size > old_size);
  74
  75    //Destroy list
  76    heap_memory.destroy_ptr(mylist);
  77
  78    return 0;
  79 }
  80 //]
  81