// (C) Copyright David Abrahams 2002.

 // (C) Copyright Jeremy Siek    2002.

 // (C) Copyright Thomas Witt    2002.

 // 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)

 #ifndef BOOST_INTEROPERABLE_23022003THW_HPP

 # define BOOST_INTEROPERABLE_23022003THW_HPP

 # include <boost/mpl/bool.hpp>

 # include <boost/mpl/or.hpp>

 # include <boost/type_traits/is_convertible.hpp>

 # include <boost/iterator/detail/config_def.hpp> // must appear last

 namespace boost

 {

   //

   // Meta function that determines whether two

   // iterator types are considered interoperable.

   //

   // Two iterator types A,B are considered interoperable if either

   // A is convertible to B or vice versa.

   // This interoperability definition is in sync with the

   // standards requirements on constant/mutable container

   // iterators (23.1 [lib.container.requirements]).

   //

   // For compilers that don't support is_convertible 

   // is_interoperable gives false positives. See comments

   // on operator implementation for consequences.

   //

   template <typename A, typename B>

   struct is_interoperable

 # ifdef BOOST_NO_STRICT_ITERATOR_INTEROPERABILITY

     : mpl::true_

 # else

     : mpl::or_<

           is_convertible< A, B >

         , is_convertible< B, A > >

 # endif

   { 

   };

 } // namespace boost

 # include <boost/iterator/detail/config_undef.hpp>

 #endif // BOOST_INTEROPERABLE_23022003THW_HPP