cgal/Kernel_23/include/CGAL/Qualified_result_of.h

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1.6 KiB
C++

// Copyright (c) 1999,2003
// Utrecht University (The Netherlands),
// ETH Zurich (Switzerland),
// INRIA Sophia-Antipolis (France),
// Max-Planck-Institute Saarbruecken (Germany),
// and Tel-Aviv University (Israel). All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 3 of the License,
// or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
//
//
// Author(s) : Sylvain Pion
#ifndef CGAL_QUALIFIED_RESULT_OF_H
#define CGAL_QUALIFIED_RESULT_OF_H
#include <boost/type_traits.hpp>
namespace CGAL {
struct Has_qrt {};
template < typename F, bool b >
struct qrt_or_not
{ typedef typename F::result_type type; };
template < typename F >
struct qrt_or_not <F, true>
{ typedef const typename F::result_type & type; };
template <typename Functor, typename P1 = void, typename P2 = void,
typename P3 = void, typename P4 = void,
typename P5 = void, typename P6 = void,
typename P7 = void, typename P8 = void>
struct Qualified_result_of
: qrt_or_not<Functor, boost::is_base_and_derived<Has_qrt, Functor>::value>
{};
} //namespace CGAL
#endif // CGAL_QUALIFIED_RESULT_OF_H