#ifndef BOOST_PFTO_HPP

 #define BOOST_PFTO_HPP

 // MS compatible compilers support #pragma once

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

 # pragma once

 #endif

 /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8

 // pfto.hpp: workarounds for compilers which have problems supporting

 // Partial Function Template Ordering (PFTO).

 // (C) Copyright 2002 Robert Ramey - http://www.rrsd.com . 

 // Use, modification and distribution is subject to 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 for updates, documentation, and revision history.

 // PFTO version is used to specify the last argument of certain functions

 // Function it is used to support  compilers that fail to support correct Partial 

 // Template Ordering

 #include <boost/config.hpp>

 // some compilers can use an exta argument and use function overloading

 // to choose desired function.  This extra argument is long in the default

 // function implementation and int for the rest.  The function is called

 // with an int argument.  This first attempts to match functions with an

 // int argument before the default one (with a long argument).  This is

 // known to function with VC 6.0. On other compilers this fails (Borland)

 // or causes other problems (GCC).  note: this 

 #if defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)

     #define BOOST_PFTO long

 #else

     #define BOOST_PFTO

 #endif

 // here's another approach.  Rather than use a default function - make sure

 // there is no default at all by requiring that all function invocations

 // have a "wrapped" argument type.  This solves a problem with VC 6.0

 // (and perhaps others) while implementing templated constructors.

 namespace boost {

 template<class T>

 struct pfto_wrapper {

     const T & t;

     operator const T & (){

         return t;

     }

     pfto_wrapper (const T & rhs) : t(rhs) {}

 };

 template<class T>

 pfto_wrapper<T> make_pfto_wrapper(const T & t, BOOST_PFTO int){

     return pfto_wrapper<T>(t);

 }

 template<class T>

 pfto_wrapper<T> make_pfto_wrapper(const pfto_wrapper<T> & t, int){

     return t;

 }

 } // namespace boost

 #ifdef BOOST_NO_FUNCTION_TEMPLATE_ORDERING

     #define BOOST_PFTO_WRAPPER(T) boost::pfto_wrapper<T>

     #define BOOST_MAKE_PFTO_WRAPPER(t) boost::make_pfto_wrapper(t, 0)

 #else

     #define BOOST_PFTO_WRAPPER(T) T

     #define BOOST_MAKE_PFTO_WRAPPER(t) t

 #endif

 #endif // BOOST_PFTO_HPP