ceph/src/boost/libs/interprocess/example/doc_managed_grow.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 #include <boost/interprocess/detail/config_begin.hpp>
  11 //[doc_managed_grow
  12 #include <boost/interprocess/managed_shared_memory.hpp>
  13 #include <boost/interprocess/managed_mapped_file.hpp>
  14 #include <cassert>
  15 //<-
  16 #include "../test/get_process_id_name.hpp"
  17 //->
  18
  19 class MyClass
  20 {
  21    //...
  22 };
  23
  24 int main()
  25 {
  26    using namespace boost::interprocess;
  27    //Remove shared memory on construction and destruction
  28    struct shm_remove
  29    {
  30    //<-
  31    #if 1
  32       shm_remove() { shared_memory_object::remove(test::get_process_id_name()); }
  33       ~shm_remove(){ shared_memory_object::remove(test::get_process_id_name()); }
  34    #else
  35    //->
  36       shm_remove() { shared_memory_object::remove("MySharedMemory"); }
  37       ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
  38    //<-
  39    #endif
  40    //->
  41    } remover;
  42    //<-
  43    (void)remover;
  44    //->
  45
  46    {
  47       //Create a managed shared memory
  48       //<-
  49       #if 1
  50       managed_shared_memory shm(create_only, test::get_process_id_name(), 1000);
  51       #else
  52       //->
  53       managed_shared_memory shm(create_only, "MySharedMemory", 1000);
  54       //<-
  55       #endif
  56       //->
  57
  58       //Check size
  59       assert(shm.get_size() == 1000);
  60       //Construct a named object
  61       MyClass *myclass = shm.construct<MyClass>("MyClass")();
  62       //The managed segment is unmapped here
  63       //<-
  64       (void)myclass;
  65       //->
  66    }
  67    {
  68       //Now that the segment is not mapped grow it adding extra 500 bytes
  69       //<-
  70       #if 1
  71       managed_shared_memory::grow(test::get_process_id_name(), 500);
  72       #else
  73       //->
  74       managed_shared_memory::grow("MySharedMemory", 500);
  75       //<-
  76       #endif
  77       //->
  78
  79       //Map it again
  80       //<-
  81       #if 1
  82       managed_shared_memory shm(open_only, test::get_process_id_name());
  83       #else
  84       //->
  85       managed_shared_memory shm(open_only, "MySharedMemory");
  86       //<-
  87       #endif
  88       //->
  89       //Check size
  90       assert(shm.get_size() == 1500);
  91       //Check "MyClass" is still there
  92       MyClass *myclass = shm.find<MyClass>("MyClass").first;
  93       assert(myclass != 0);
  94       //<-
  95       (void)myclass;
  96       //->
  97       //The managed segment is unmapped here
  98    }
  99    {
 100       //Now minimize the size of the segment
 101       //<-
 102       #if 1
 103       managed_shared_memory::shrink_to_fit(test::get_process_id_name());
 104       #else
 105       //->
 106       managed_shared_memory::shrink_to_fit("MySharedMemory");
 107       //<-
 108       #endif
 109       //->
 110
 111       //Map it again
 112       //<-
 113       #if 1
 114       managed_shared_memory shm(open_only, test::get_process_id_name());
 115       #else
 116       //->
 117       managed_shared_memory shm(open_only, "MySharedMemory");
 118       //<-
 119       #endif
 120       //->
 121       //Check size
 122       assert(shm.get_size() < 1000);
 123       //Check "MyClass" is still there
 124       MyClass *myclass = shm.find<MyClass>("MyClass").first;
 125       assert(myclass != 0);
 126       //The managed segment is unmapped here
 127       //<-
 128       (void)myclass;
 129       //->
 130    }
 131    return 0;
 132 }
 133 //]
 134 #include <boost/interprocess/detail/config_end.hpp>