williamr@2: // (C) Copyright David Abrahams 2002.
williamr@2: // (C) Copyright Jeremy Siek    2002.
williamr@2: // (C) Copyright Thomas Witt    2002.
williamr@2: // Distributed under the Boost Software License, Version 1.0. (See
williamr@2: // accompanying file LICENSE_1_0.txt or copy at
williamr@2: // http://www.boost.org/LICENSE_1_0.txt)
williamr@2: #ifndef BOOST_INTEROPERABLE_23022003THW_HPP
williamr@2: # define BOOST_INTEROPERABLE_23022003THW_HPP
williamr@2: 
williamr@2: # include <boost/mpl/bool.hpp>
williamr@2: # include <boost/mpl/or.hpp>
williamr@2: 
williamr@2: # include <boost/type_traits/is_convertible.hpp>
williamr@2: 
williamr@2: # include <boost/iterator/detail/config_def.hpp> // must appear last
williamr@2: 
williamr@2: namespace boost
williamr@2: {
williamr@2: 
williamr@2:   //
williamr@2:   // Meta function that determines whether two
williamr@2:   // iterator types are considered interoperable.
williamr@2:   //
williamr@2:   // Two iterator types A,B are considered interoperable if either
williamr@2:   // A is convertible to B or vice versa.
williamr@2:   // This interoperability definition is in sync with the
williamr@2:   // standards requirements on constant/mutable container
williamr@2:   // iterators (23.1 [lib.container.requirements]).
williamr@2:   //
williamr@2:   // For compilers that don't support is_convertible 
williamr@2:   // is_interoperable gives false positives. See comments
williamr@2:   // on operator implementation for consequences.
williamr@2:   //
williamr@2:   template <typename A, typename B>
williamr@2:   struct is_interoperable
williamr@2: # ifdef BOOST_NO_STRICT_ITERATOR_INTEROPERABILITY
williamr@2:     : mpl::true_
williamr@2: # else
williamr@2:     : mpl::or_<
williamr@2:           is_convertible< A, B >
williamr@2:         , is_convertible< B, A > >
williamr@2: # endif
williamr@2:   { 
williamr@2:   };
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: # include <boost/iterator/detail/config_undef.hpp>
williamr@2: 
williamr@2: #endif // BOOST_INTEROPERABLE_23022003THW_HPP