1 // Low-level functions for atomic operations: Generic version -*- C++ -*- 2 3 // Copyright (C) 1999, 2001, 2002, 2003, 2004, 2005, 2006 4 // Free Software Foundation, Inc. 5 // 6 // This file is part of the GNU ISO C++ Library. This library is free 7 // software; you can redistribute it and/or modify it under the 8 // terms of the GNU General Public License as published by the 9 // Free Software Foundation; either version 2, or (at your option) 10 // any later version. 11 12 // This library is distributed in the hope that it will be useful, 13 // but WITHOUT ANY WARRANTY; without even the implied warranty of 14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 // GNU General Public License for more details. 16 17 // You should have received a copy of the GNU General Public License along 18 // with this library; see the file COPYING. If not, write to the Free 19 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 20 // USA. 21 22 // As a special exception, you may use this file as part of a free software 23 // library without restriction. Specifically, if other files instantiate 24 // templates or use macros or inline functions from this file, or you compile 25 // this file and link it with other files to produce an executable, this 26 // 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 38 namespace 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