text: //////////////////////////////////////////////////////////////////////////////
  //
  // (C) Copyright Ion Gaztanaga 2009. Distributed under the Boost
  // Software License, Version 1.0. (See accompanying file
  // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  //
  // See http://www.boost.org/libs/interprocess for documentation.
  //
  //////////////////////////////////////////////////////////////////////////////
  
  #ifndef BOOST_INTERPROCESS_XSI_KEY_HPP
  #define BOOST_INTERPROCESS_XSI_KEY_HPP
  
  #ifndef BOOST_CONFIG_HPP
  #  include <boost/config.hpp>
  #endif
  #
  #if defined(BOOST_HAS_PRAGMA_ONCE)
  #  pragma once
  #endif
  
  #include <boost/interprocess/detail/config_begin.hpp>
  #include <boost/interprocess/detail/workaround.hpp>
  #include <boost/detail/workaround.hpp>
  
  #if !defined(BOOST_INTERPROCESS_XSI_SHARED_MEMORY_OBJECTS)
  #error "This header can't be used in operating systems without XSI (System V) shared memory support"
  #endif
  
  #include <boost/interprocess/creation_tags.hpp>
  #include <boost/interprocess/exceptions.hpp>
  #include <boost/interprocess/detail/utilities.hpp>
  #include <boost/move/utility_core.hpp>
  #include <boost/interprocess/detail/os_file_functions.hpp>
  #include <boost/interprocess/interprocess_fwd.hpp>
  #include <boost/interprocess/exceptions.hpp>
  #include <sys/types.h>
  #include <sys/ipc.h>
  #include <cstddef>
  #include <boost/cstdint.hpp>
  
  //!\file
  //!Describes a class representing a xsi key type.
  
  namespace boost {
  namespace interprocess {
  
  //!A class that wraps XSI (System V) key_t type.
  //!This type calculates key_t from path and id using ftok,
  //!sets key to a specified value,
  //!or sets key to IPC_PRIVATE using the default constructor.
  class xsi_key
  {
     public:
  
     //!Default constructor.
     //!Represents a private xsi_key.
     xsi_key()
        : m_key(IPC_PRIVATE)
     {}
  
     //!Creates a new XSI key using a specified value. Constructor is explicit to avoid ambiguity with shmid.
     explicit xsi_key(key_t key)
        : m_key(key)
     {}
  
     //!Creates a new XSI  shared memory with a key obtained from a call to ftok (with path
     //!"path" and id "id"), of size "size" and permissions "perm".
     //!If the shared memory previously exists, throws an error.
     xsi_key(const char *path, boost::uint8_t id)
     {
        key_t key;
        if(path){
           key  = ::ftok(path, id);
           if(((key_t)-1) == key){
              error_info err = system_error_code();
              throw interprocess_exception(err);
           }
        }
        else{
           key = IPC_PRIVATE;
        }
        m_key = key;
     }
  
     //!Returns the internal key_t value
     key_t get_key() const
     {  return m_key;  }
  
     #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
     private:
     key_t m_key;
     #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
  };
  
  }  //namespace interprocess {
  }  //namespace boost {
  
  #include <boost/interprocess/detail/config_end.hpp>
  
  #endif   //BOOST_INTERPROCESS_XSI_KEY_HPP
  