libs/interprocess/example/doc_spawn_vector.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_spawn_vector
  13 #include <boost/interprocess/managed_shared_memory.hpp>
  14 #include <boost/interprocess/containers/vector.hpp>
  15 #include <boost/interprocess/allocators/allocator.hpp>
  16 #include <string>
  17 #include <cstdlib> //std::system
  18 //<-
  19 #include "../test/get_process_id_name.hpp"
  20 //->
  21
  22 using namespace boost::interprocess;
  23
  24 //Define an STL compatible allocator of ints that allocates from the managed_shared_memory.
  25 //This allocator will allow placing containers in the segment
  26 typedef allocator<int, managed_shared_memory::segment_manager>  ShmemAllocator;
  27
  28 //Alias a vector that uses the previous STL-like allocator so that allocates
  29 //its values from the segment
  30 typedef vector<int, ShmemAllocator> MyVector;
  31
  32 //Main function. For parent process argc == 1, for child process argc == 2
  33 int main(int argc, char *argv[])
  34 {
  35    if(argc == 1){ //Parent process
  36       //Remove shared memory on construction and destruction
  37       struct shm_remove
  38       {
  39       //<-
  40       #if 1
  41          shm_remove() { shared_memory_object::remove(test::get_process_id_name()); }
  42          ~shm_remove(){ shared_memory_object::remove(test::get_process_id_name()); }
  43       #else
  44       //->
  45          shm_remove() { shared_memory_object::remove("MySharedMemory"); }
  46          ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
  47       //<-
  48       #endif
  49       //->
  50       } remover;
  51
  52       //Create a new segment with given name and size
  53       //<-
  54       #if 1
  55       managed_shared_memory segment(create_only, test::get_process_id_name(), 65536);
  56       #else
  57       //->
  58       managed_shared_memory segment(create_only, "MySharedMemory", 65536);
  59       //<-
  60       #endif
  61       //->
  62
  63       //Initialize shared memory STL-compatible allocator
  64       const ShmemAllocator alloc_inst (segment.get_segment_manager());
  65
  66       //Construct a vector named "MyVector" in shared memory with argument alloc_inst
  67       MyVector *myvector = segment.construct<MyVector>("MyVector")(alloc_inst);
  68
  69       for(int i = 0; i < 100; ++i)  //Insert data in the vector
  70          myvector->push_back(i);
  71
  72       //Launch child process
  73       std::string s(argv[0]); s += " child ";
  74       //<-
  75       s += test::get_process_id_name();
  76       //->
  77       if(0 != std::system(s.c_str()))
  78          return 1;
  79
  80       //Check child has destroyed the vector
  81       if(segment.find<MyVector>("MyVector").first)
  82          return 1;
  83    }
  84    else{ //Child process
  85       //Open the managed segment
  86       //<-
  87       #if 1
  88       managed_shared_memory segment(open_only, argv[2]);
  89       #else
  90       //->
  91       managed_shared_memory segment(open_only, "MySharedMemory");
  92       //<-
  93       #endif
  94       //->
  95
  96       //Find the vector using the c-string name
  97       MyVector *myvector = segment.find<MyVector>("MyVector").first;
  98
  99       //Use vector in reverse order
 100       std::sort(myvector->rbegin(), myvector->rend());
 101
 102       //When done, destroy the vector from the segment
 103       segment.destroy<MyVector>("MyVector");
 104    }
 105
 106    return 0;
 107 };
 108
 109 //]
 110 #include <boost/interprocess/detail/config_end.hpp>