libs/interprocess/example/comp_doc_anonymous_conditionA.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 //[doc_anonymous_conditionA
  12 #include <boost/interprocess/shared_memory_object.hpp>
  13 #include <boost/interprocess/mapped_region.hpp>
  14 #include <boost/interprocess/sync/scoped_lock.hpp>
  15 #include <iostream>
  16 #include <cstdio>
  17 #include "doc_anonymous_condition_shared_data.hpp"
  18
  19 using namespace boost::interprocess;
  20
  21 int main ()
  22 {
  23
  24    //Erase previous shared memory and schedule erasure on exit
  25    struct shm_remove
  26    {
  27       shm_remove() { shared_memory_object::remove("MySharedMemory"); }
  28       ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
  29    } remover;
  30
  31    //Create a shared memory object.
  32    shared_memory_object shm
  33       (create_only               //only create
  34       ,"MySharedMemory"           //name
  35       ,read_write                //read-write mode
  36       );
  37    try{
  38       //Set size
  39       shm.truncate(sizeof(trace_queue));
  40
  41       //Map the whole shared memory in this process
  42       mapped_region region
  43          (shm                       //What to map
  44          ,read_write //Map it as read-write
  45          );
  46
  47       //Get the address of the mapped region
  48       void * addr       = region.get_address();
  49
  50       //Construct the shared structure in memory
  51       trace_queue * data = new (addr) trace_queue;
  52
  53       const int NumMsg = 100;
  54
  55       for(int i = 0; i < NumMsg; ++i){
  56          scoped_lock<interprocess_mutex> lock(data->mutex);
  57          if(data->message_in){
  58             data->cond_full.wait(lock);
  59          }
  60          if(i == (NumMsg-1))
  61             std::sprintf(data->items, "%s", "last message");
  62          else
  63             std::sprintf(data->items, "%s_%d", "my_trace", i);
  64
  65          //Notify to the other process that there is a message
  66          data->cond_empty.notify_one();
  67
  68          //Mark message buffer as full
  69          data->message_in = true;
  70       }
  71    }
  72    catch(interprocess_exception &ex){
  73       std::cout << ex.what() << std::endl;
  74       return 1;
  75    }
  76
  77    return 0;
  78 }
  79 //]