rb_tree

gcc-you can use this code to learn something about gcc, and inquire further into linux,

// rb_tree extension -*- C++ -*-

// Copyright (C) 2002 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING.  If not, write to the Free
// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.

// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */

/** @file ext/rb_tree
 *  This file is a GNU extension to the Standard C++ Library (possibly
 *  containing extensions from the HP/SGI STL subset).  You should only
 *  include this header if you are using GCC 3 or later.
 */

#ifndef _EXT_RB_TREE
#define _EXT_RB_TREE

#pragma GCC system_header
#include <bits/stl_tree.h>

namespace __gnu_cxx
{
using std::_Rb_tree;
using std::allocator;

// Class rb_tree is not part of the C++ standard.  It is provided for
// compatibility with the HP STL.

/**
 *  This is an SGI extension.
 *  @ingroup SGIextensions
 *  @doctodo
*/
template <class _Key, class _Value, class _KeyOfValue, class _Compare,
          class _Alloc = allocator<_Value> >
struct rb_tree : public _Rb_tree<_Key, _Value, _KeyOfValue, _Compare, _Alloc>
{
  typedef _Rb_tree<_Key, _Value, _KeyOfValue, _Compare, _Alloc> _Base;
  typedef typename _Base::allocator_type allocator_type;

  rb_tree(const _Compare& __comp = _Compare(),
          const allocator_type& __a = allocator_type())
    : _Base(__comp, __a) {}
  
  ~rb_tree() {}
};

} // namespace __gnu_cxx

#endif /* _EXT_RB_TREE */