ceph/src/boost/libs/interprocess/example/doc_xsi_shared_memory.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
  11 #include <boost/interprocess/detail/workaround.hpp>
  12
  13 #if defined(BOOST_INTERPROCESS_XSI_SHARED_MEMORY_OBJECTS) || defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
  14
  15 //[doc_xsi_shared_memory
  16 #include <boost/interprocess/xsi_shared_memory.hpp>
  17 #include <boost/interprocess/mapped_region.hpp>
  18 #include <cstring>
  19 #include <cstdlib>
  20 #include <string>
  21
  22 using namespace boost::interprocess;
  23
  24 void remove_old_shared_memory(const xsi_key &key)
  25 {
  26    BOOST_TRY{
  27       xsi_shared_memory xsi(open_only, key);
  28       xsi_shared_memory::remove(xsi.get_shmid());
  29    }
  30    BOOST_CATCH(interprocess_exception &e){
  31       if(e.get_error_code() != not_found_error)
  32          BOOST_RETHROW
  33    } BOOST_CATCH_END
  34 }
  35
  36 int main(int argc, char *argv[])
  37 {
  38    if(argc == 1){  //Parent process
  39       //Build XSI key (ftok based)
  40       xsi_key key(argv[0], 1);
  41
  42       remove_old_shared_memory(key);
  43
  44       //Create a shared memory object.
  45       xsi_shared_memory shm (create_only, key, 1000);
  46
  47       //Remove shared memory on destruction
  48       struct shm_remove
  49       {
  50          int shmid_;
  51          shm_remove(int shmid) : shmid_(shmid){}
  52          ~shm_remove(){ xsi_shared_memory::remove(shmid_); }
  53       } remover(shm.get_shmid());
  54
  55       //Map the whole shared memory in this process
  56       mapped_region region(shm, read_write);
  57
  58       //Write all the memory to 1
  59       std::memset(region.get_address(), 1, region.get_size());
  60
  61       //Launch child process
  62       std::string s(argv[0]); s += " child ";
  63       if(0 != std::system(s.c_str()))
  64          return 1;
  65    }
  66    else{
  67       //Build XSI key (ftok based)
  68       xsi_key key(argv[0], 1);
  69
  70       //Create a shared memory object.
  71       xsi_shared_memory shm (open_only, key);
  72
  73       //Map the whole shared memory in this process
  74       mapped_region region(shm, read_only);
  75
  76       //Check that memory was initialized to 1
  77       char *mem = static_cast<char*>(region.get_address());
  78       for(std::size_t i = 0; i < region.get_size(); ++i)
  79          if(*mem++ != 1)
  80             return 1;   //Error checking memory
  81    }
  82    return 0;
  83 }
  84 //]
  85
  86 #else //BOOST_INTERPROCESS_XSI_SHARED_MEMORY_OBJECTS
  87
  88 int main()
  89 {
  90    return 0;
  91 }
  92
  93 #endif //BOOST_INTERPROCESS_XSI_SHARED_MEMORY_OBJECTS
  94
  95