ceph/src/boost/libs/interprocess/example/doc_ipc_message.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 #include <boost/interprocess/detail/workaround.hpp>
  12 //[doc_ipc_message
  13 #include <boost/interprocess/managed_shared_memory.hpp>
  14 #include <cstdlib> //std::system
  15 #include <sstream>
  16 //<-
  17 #include "../test/get_process_id_name.hpp"
  18 //->
  19
  20 int main (int argc, char *argv[])
  21 {
  22    using namespace boost::interprocess;
  23    if(argc == 1){  //Parent process
  24       //Remove shared memory on construction and destruction
  25       struct shm_remove
  26       {
  27       //<-
  28       #if 1
  29          shm_remove() {  shared_memory_object::remove(test::get_process_id_name()); }
  30          ~shm_remove(){  shared_memory_object::remove(test::get_process_id_name()); }
  31       #else
  32       //->
  33          shm_remove() {  shared_memory_object::remove("MySharedMemory"); }
  34          ~shm_remove(){  shared_memory_object::remove("MySharedMemory"); }
  35       //<-
  36       #endif
  37       //->
  38       } remover;
  39       //<-
  40       (void)remover;
  41       //->
  42
  43       //Create a managed shared memory segment
  44       //<-
  45       #if 1
  46       managed_shared_memory segment(create_only, test::get_process_id_name(), 65536);
  47       #else
  48       //->
  49       managed_shared_memory segment(create_only, "MySharedMemory", 65536);
  50       //<-
  51       #endif
  52       //->
  53
  54       //Allocate a portion of the segment (raw memory)
  55       managed_shared_memory::size_type free_memory = segment.get_free_memory();
  56       void * shptr = segment.allocate(1024/*bytes to allocate*/);
  57
  58       //Check invariant
  59       if(free_memory <= segment.get_free_memory())
  60          return 1;
  61
  62       //An handle from the base address can identify any byte of the shared
  63       //memory segment even if it is mapped in different base addresses
  64       managed_shared_memory::handle_t handle = segment.get_handle_from_address(shptr);
  65       std::stringstream s;
  66       s << argv[0] << " " << handle;
  67       //<-
  68       s << " " << test::get_process_id_name();
  69       //->
  70       s << std::ends;
  71       //Launch child process
  72       if(0 != std::system(s.str().c_str()))
  73          return 1;
  74       //Check memory has been freed
  75       if(free_memory != segment.get_free_memory())
  76          return 1;
  77    }
  78    else{
  79       //Open managed segment
  80       //<-
  81       #if 1
  82       managed_shared_memory segment(open_only, argv[2]);
  83       #else
  84       //->
  85       managed_shared_memory segment(open_only, "MySharedMemory");
  86       //<-
  87       #endif
  88       //->
  89
  90       //An handle from the base address can identify any byte of the shared
  91       //memory segment even if it is mapped in different base addresses
  92       managed_shared_memory::handle_t handle = 0;
  93
  94       //Obtain handle value
  95       std::stringstream s; s << argv[1]; s >> handle;
  96
  97       //Get buffer local address from handle
  98       void *msg = segment.get_address_from_handle(handle);
  99
 100       //Deallocate previously allocated memory
 101       segment.deallocate(msg);
 102    }
 103    return 0;
 104 }
 105 //]
 106 #include <boost/interprocess/detail/config_end.hpp>