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// Boost.Signals2 library

// Copyright Frank Mori Hess 2007,2009.
// Copyright Timmo Stange 2007.
// Copyright Douglas Gregor 2001-2004. Use, modification and
// distribution is subject to the Boost Software License, Version
// 1.0. (See accompanying file LICENSE_1_0.txt or copy at

// Compatibility class to ease porting from the original
// Boost.Signals library.  However,
// boost::signals2::trackable is NOT thread-safe.

// For more information, see


#include <boost/assert.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/weak_ptr.hpp>

namespace boost {
  namespace signals2 {
    namespace detail
        class tracked_objects_visitor;
        // trackable_pointee is used to identify the tracked shared_ptr 
        // originating from the signals2::trackable class.  These tracked
        // shared_ptr are special in that we shouldn't bother to
        // increment their use count during signal invocation, since
        // they don't actually control the lifetime of the
        // signals2::trackable object they are associated with.
        class trackable_pointee
    class trackable {
      trackable(): _tracked_ptr(static_cast<detail::trackable_pointee*>(0)) {}
      trackable(const trackable &): _tracked_ptr(static_cast<detail::trackable_pointee*>(0)) {}
      trackable& operator=(const trackable &)
          return *this;
      ~trackable() {}
      friend class detail::tracked_objects_visitor;
      weak_ptr<detail::trackable_pointee> get_weak_ptr() const
          return _tracked_ptr;

      shared_ptr<detail::trackable_pointee> _tracked_ptr;
  } // end namespace signals2
} // end namespace boost