libs/interprocess/example/doc_where_allocate.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_where_allocate
  13 #include <boost/interprocess/managed_shared_memory.hpp>
  14 #include <boost/interprocess/containers/vector.hpp>
  15 #include <boost/interprocess/containers/string.hpp>
  16 #include <boost/interprocess/allocators/allocator.hpp>
  17 //<-
  18 #include "../test/get_process_id_name.hpp"
  19 //->
  20
  21 int main ()
  22 {
  23    using namespace boost::interprocess;
  24    //Typedefs
  25    typedef allocator<char, managed_shared_memory::segment_manager>
  26       CharAllocator;
  27    typedef basic_string<char, std::char_traits<char>, CharAllocator>
  28       MyShmString;
  29    typedef allocator<MyShmString, managed_shared_memory::segment_manager>
  30       StringAllocator;
  31    typedef vector<MyShmString, StringAllocator>
  32       MyShmStringVector;
  33
  34    //Open shared memory
  35    //Remove shared memory on construction and destruction
  36    struct shm_remove
  37    {
  38    //<-
  39    #if 1
  40       shm_remove() { shared_memory_object::remove(test::get_process_id_name()); }
  41       ~shm_remove(){ shared_memory_object::remove(test::get_process_id_name()); }
  42    #else
  43    //->
  44       shm_remove() { shared_memory_object::remove("MySharedMemory"); }
  45       ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
  46    //<-
  47    #endif
  48    //->
  49    } remover;
  50
  51    //<-
  52    #if 1
  53    managed_shared_memory shm(create_only, test::get_process_id_name(), 10000);
  54    #else
  55    //->
  56    managed_shared_memory shm(create_only, "MySharedMemory", 10000);
  57    //<-
  58    #endif
  59    //->
  60
  61    //Create allocators
  62    CharAllocator     charallocator  (shm.get_segment_manager());
  63    StringAllocator   stringallocator(shm.get_segment_manager());
  64
  65    //This string is in only in this process (the pointer pointing to the
  66    //buffer that will hold the text is not in shared memory).
  67    //But the buffer that will hold "this is my text" is allocated from
  68    //shared memory
  69    MyShmString mystring(charallocator);
  70    mystring = "this is my text";
  71
  72    //This vector is only in this process (the pointer pointing to the
  73    //buffer that will hold the MyShmString-s is not in shared memory).
  74    //But the buffer that will hold 10 MyShmString-s is allocated from
  75    //shared memory using StringAllocator. Since strings use a shared
  76    //memory allocator (CharAllocator) the 10 buffers that hold
  77    //"this is my text" text are also in shared memory.
  78    MyShmStringVector myvector(stringallocator);
  79    myvector.insert(myvector.begin(), 10, mystring);
  80
  81    //This vector is fully constructed in shared memory. All pointers
  82    //buffers are constructed in the same shared memory segment
  83    //This vector can be safely accessed from other processes.
  84    MyShmStringVector *myshmvector =
  85       shm.construct<MyShmStringVector>("myshmvector")(stringallocator);
  86    myshmvector->insert(myshmvector->begin(), 10, mystring);
  87
  88    //Destroy vector. This will free all strings that the vector contains
  89    shm.destroy_ptr(myshmvector);
  90    return 0;
  91 }
  92 //]
  93 #include <boost/interprocess/detail/config_end.hpp>