text: //
  // ip_hash_test.cpp
  //
  // Copyright 2011 Peter Dimov
  //
  // 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
  //
  
  #include <boost/intrusive_ptr.hpp>
  #include <boost/functional/hash.hpp>
  #include <boost/detail/lightweight_test.hpp>
  
  class base
  {
  private:
  
      int use_count_;
  
      base(base const &);
      base & operator=(base const &);
  
  protected:
  
      base(): use_count_(0)
      {
      }
  
      virtual ~base()
      {
      }
  
  public:
  
      long use_count() const
      {
          return use_count_;
      }
  
      inline friend void intrusive_ptr_add_ref(base * p)
      {
          ++p->use_count_;
      }
  
      inline friend void intrusive_ptr_release(base * p)
      {
          if(--p->use_count_ == 0) delete p;
      }
  };
  
  struct X: public base
  {
  };
  
  int main()
  {
      boost::hash< boost::intrusive_ptr<X> > hasher;
  
      boost::intrusive_ptr<X> p1, p2( p1 ), p3( new X ), p4( p3 ), p5( new X );
  
      BOOST_TEST_EQ( p1, p2 );
      BOOST_TEST_EQ( hasher( p1 ), hasher( p2 ) );
  
      BOOST_TEST_NE( p1, p3 );
      BOOST_TEST_NE( hasher( p1 ), hasher( p3 ) );
  
      BOOST_TEST_EQ( p3, p4 );
      BOOST_TEST_EQ( hasher( p3 ), hasher( p4 ) );
  
      BOOST_TEST_NE( p3, p5 );
      BOOST_TEST_NE( hasher( p3 ), hasher( p5 ) );
  
      return boost::report_errors();
  }
  