#ifndef BOOST_DETAIL_SP_COUNTED_BASE_PT_HPP_INCLUDED

 #define BOOST_DETAIL_SP_COUNTED_BASE_PT_HPP_INCLUDED

 // MS compatible compilers support #pragma once

 #if defined(_MSC_VER) && (_MSC_VER >= 1020)

 # pragma once

 #endif

 //

 //  detail/sp_counted_base_pt.hpp

 //

 //  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.

 //  Copyright 2004-2005 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 <typeinfo>

 #include <pthread.h>

 namespace boost

 {

 namespace detail

 {

 class sp_counted_base

 {

 private:

     sp_counted_base( sp_counted_base const & );

     sp_counted_base & operator= ( sp_counted_base const & );

     long use_count_;        // #shared

     long weak_count_;       // #weak + (#shared != 0)

     mutable pthread_mutex_t m_;

 public:

     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )

     {

 // HPUX 10.20 / DCE has a nonstandard pthread_mutex_init

 #if defined(__hpux) && defined(_DECTHREADS_)

         pthread_mutex_init( &m_, pthread_mutexattr_default );

 #else

         pthread_mutex_init( &m_, 0 );

 #endif

     }

     virtual ~sp_counted_base() // nothrow

     {

         pthread_mutex_destroy( &m_ );

     }

     // dispose() is called when use_count_ drops to zero, to release

     // the resources managed by *this.

     virtual void dispose() = 0; // nothrow

     // destroy() is called when weak_count_ drops to zero.

     virtual void destroy() // nothrow

     {

         delete this;

     }

     virtual void * get_deleter( std::type_info const & ti ) = 0;

     void add_ref_copy()

     {

         pthread_mutex_lock( &m_ );

         ++use_count_;

         pthread_mutex_unlock( &m_ );

     }

     bool add_ref_lock() // true on success

     {

         pthread_mutex_lock( &m_ );

         bool r = use_count_ == 0? false: ( ++use_count_, true );

         pthread_mutex_unlock( &m_ );

         return r;

     }

     void release() // nothrow

     {

         pthread_mutex_lock( &m_ );

         long new_use_count = --use_count_;

         pthread_mutex_unlock( &m_ );

         if( new_use_count == 0 )

         {

             dispose();

             weak_release();

         }

     }

     void weak_add_ref() // nothrow

     {

         pthread_mutex_lock( &m_ );

         ++weak_count_;

         pthread_mutex_unlock( &m_ );

     }

     void weak_release() // nothrow

     {

         pthread_mutex_lock( &m_ );

         long new_weak_count = --weak_count_;

         pthread_mutex_unlock( &m_ );

         if( new_weak_count == 0 )

         {

             destroy();

         }

     }

     long use_count() const // nothrow

     {

         pthread_mutex_lock( &m_ );

         long r = use_count_;

         pthread_mutex_unlock( &m_ );

         return r;

     }

 };

 } // namespace detail

 } // namespace boost

 #endif  // #ifndef BOOST_DETAIL_SP_COUNTED_BASE_PT_HPP_INCLUDED