cgal/BGL/include/CGAL/boost/graph/internal/Has_member_id.h

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// Copyright (c) 2016 GeometryFactory (France). All rights reserved.
//
// This file is part of CGAL (www.cgal.org)
//
// $URL$
// $Id$
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
// Author(s) : Jane Tournois
#ifndef CGAL_HAS_MEMBER_ID_H
#define CGAL_HAS_MEMBER_ID_H
namespace CGAL {
namespace internal {
template <typename Type>
class Has_member_id
{
typedef char yes[1];
typedef char no[2];
struct BaseWithId
{
void id(){}
};
struct Base : public Type, public BaseWithId {};
template <typename T, T t>
class Helper{};
template <typename U>
static no &check(U*, Helper<void (BaseWithId::*)(), &U::id>* = 0);
static yes &check(...);
public:
static const bool value = (sizeof(yes) == sizeof(check((Base*)(0))));
};
} // internal
} // cgal
#endif /* CGAL_HAS_MEMBER_ID_H */