1 /* Copyright (C) 2003-2015 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
19 #ifndef _BITS_ATOMIC_H
20 #define _BITS_ATOMIC_H 1
22 /* We have by default no support for atomic operations. So define
23 them non-atomic. If this is a problem somebody will have to come
24 up with real definitions. */
26 /* The only basic operation needed is compare and exchange. */
27 #define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \
28 ({ __typeof (mem) __gmemp = (mem); \
29 __typeof (*mem) __gret = *__gmemp; \
30 __typeof (*mem) __gnewval = (newval); \
32 if (__gret == (oldval)) \
33 *__gmemp = __gnewval; \
36 #define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
37 ({ __typeof (mem) __gmemp = (mem); \
38 __typeof (*mem) __gnewval = (newval); \
40 *__gmemp == (oldval) ? (*__gmemp = __gnewval, 0) : 1; })
42 #endif /* bits/atomic.h */