ceph/src/boost/libs/interprocess/example/comp_doc_anonymous_mutexA.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_anonymous_mutexA
  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 "doc_anonymous_mutex_shared_data.hpp"
  16 #include <iostream>
  17 #include <cstdio>
  18
  19 using namespace boost::interprocess;
  20
  21 int main ()
  22 {
  23    try{
  24       //Remove shared memory on construction and destruction
  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       (void)remover;
  32       //->
  33
  34       //Create a shared memory object.
  35       shared_memory_object shm
  36          (create_only               //only create
  37          ,"MySharedMemory"          //name
  38          ,read_write   //read-write mode
  39          );
  40
  41       //Set size
  42       shm.truncate(sizeof(shared_memory_log));
  43
  44       //Map the whole shared memory in this process
  45       mapped_region region
  46          (shm                       //What to map
  47          ,read_write   //Map it as read-write
  48          );
  49
  50       //Get the address of the mapped region
  51       void * addr       = region.get_address();
  52
  53       //Construct the shared structure in memory
  54       shared_memory_log * data = new (addr) shared_memory_log;
  55
  56       //Write some logs
  57       for(int i = 0; i < shared_memory_log::NumItems; ++i){
  58          //Lock the mutex
  59          scoped_lock<interprocess_mutex> lock(data->mutex);
  60          std::sprintf(data->items[(data->current_line++) % shared_memory_log::NumItems]
  61                   ,"%s_%d", "process_a", i);
  62          if(i == (shared_memory_log::NumItems-1))
  63             data->end_a = true;
  64          //Mutex is released here
  65       }
  66
  67       //Wait until the other process ends
  68       while(1){
  69          scoped_lock<interprocess_mutex> lock(data->mutex);
  70          if(data->end_b)
  71             break;
  72       }
  73    }
  74    catch(interprocess_exception &ex){
  75       std::cout << ex.what() << std::endl;
  76       return 1;
  77    }
  78    return 0;
  79 }
  80 //]
  81 #include <boost/interprocess/detail/config_end.hpp>