shared_memory.h

Go to the documentation of this file.

#ifndef SHARED_MEMORY_CLASS
#define SHARED_MEMORY_CLASS
 
/*****************************************************************************\
*                                                                             *
*  Name   : shared_memory                                                     *
*  Author : Chris Koeritz                                                     *
*                                                                             *
*******************************************************************************
* Copyright (c) 2002-$now By Author.  This program is free software; you can  *
* redistribute it and/or modify it under the terms of the GNU General Public  *
* License as published by the Free Software Foundation; either version 2 of   *
* the License or (at your option) any later version.  This is online at:      *
*     http://www.fsf.org/copyleft/gpl.html                                    *
* Please send any updates to: fred@gruntose.com                               *
\*****************************************************************************/
 
#include <basis/contracts.h>
#include <filesystem/byte_filer.h>
#include <processes/rendezvous.h>
 
namespace application {
 
 
class shared_memory : public virtual basis::root_object
{
public:
  shared_memory(int size, const char *identity);
 
  virtual ~shared_memory();
 
  DEFINE_CLASS_NAME("shared_memory");
 
  bool valid() const { return _valid; }
 
  int size() const { return _size; }
 
  const basis::astring &identity() const;
 
  bool first_usage(basis::abyte *locked_memory, int max_compare);
 
  basis::abyte *lock();
 
  void unlock(basis::abyte * &to_unlock);
 
  static basis::astring unique_shared_mem_identifier(int sequencer);
 
private:
  processes::rendezvous *_locking;  
#ifdef __UNIX__
  int _the_memory;  
#elif defined(__WIN32__)
  void *_the_memory;  
#endif
  bool _valid;  
  basis::astring *_identity;  
  int _size;  
 
  // these do the actual work of getting the memory.
  basis::abyte *locked_grab_memory();
  void locked_release_memory(basis::abyte * &to_unlock);
 
  static basis::astring special_filename(const basis::astring &identity);
 
  // forbidden.
  shared_memory(const shared_memory &);
  shared_memory &operator =(const shared_memory &);
};
 
} //namespace.
 
 
#endif  // outer guard.