atomicity.h revision 169691 
176264Sgreen// Low-level functions for atomic operations: Generic version  -*- C++ -*-
276264Sgreen
3255460Sdes// Copyright (C) 1999, 2001, 2002, 2003, 2004, 2005, 2006
4255460Sdes// Free Software Foundation, Inc.
576264Sgreen//
6126282Sdes// This file is part of the GNU ISO C++ Library.  This library is free
7158519Sdes// software; you can redistribute it and/or modify it under the
8293396Sbdrewery// terms of the GNU General Public License as published by the
976264Sgreen// Free Software Foundation; either version 2, or (at your option)
10255460Sdes// any later version.
11255460Sdes
12255386Sdes// This library is distributed in the hope that it will be useful,
1376264Sgreen// but WITHOUT ANY WARRANTY; without even the implied warranty of
14255460Sdes// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15255460Sdes// GNU General Public License for more details.
16255460Sdes
17255460Sdes// You should have received a copy of the GNU General Public License along
18255460Sdes// with this library; see the file COPYING.  If not, write to the Free
19255460Sdes// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
20255460Sdes// USA.
21255460Sdes
22255460Sdes// As a special exception, you may use this file as part of a free software
23255460Sdes// library without restriction.  Specifically, if other files instantiate
2476264Sgreen// templates or use macros or inline functions from this file, or you compile
2576264Sgreen// this file and link it with other files to produce an executable, this
2676264Sgreen// file does not by itself cause the resulting executable to be covered by
27// the GNU General Public License.  This exception does not however
28// invalidate any other reasons why the executable file might be covered by
29// the GNU General Public License.
30
31/** @file ext/atomicity.h
32 *  This file is a GNU extension to the Standard C++ Library.
33 */
34
35#include <ext/atomicity.h>
36#include <ext/concurrence.h>
37
38namespace
39{
40  __gnu_cxx::__mutex atomic_mutex;
41} // anonymous namespace
42
43_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
44
45  _Atomic_word
46  __attribute__ ((__unused__))
47  __exchange_and_add(volatile _Atomic_word* __mem, int __val)
48  {
49    __gnu_cxx::__scoped_lock sentry(atomic_mutex);
50    _Atomic_word __result;
51    __result = *__mem;
52    *__mem += __val;
53    return __result;
54  }
55
56  void
57  __attribute__ ((__unused__))
58  __atomic_add(volatile _Atomic_word* __mem, int __val)
59  { __exchange_and_add(__mem, __val); }
60
61_GLIBCXX_END_NAMESPACE
62