# atomic_word.h

Go to the documentation of this file.

    00001 // Low-level type for atomic operations -*- C++ -*-
    00002
    00003 // Copyright (C) 2004 Free Software Foundation, Inc.
    00004 //
    00005 // This file is part of the GNU ISO C++ Library.  This library is free
    00006 // software; you can redistribute it and/or modify it under the
    00007 // terms of the GNU General Public License as published by the
    00008 // Free Software Foundation; either version 2, or (at your option)
    00009 // any later version.
    00010
    00011 // This library is distributed in the hope that it will be useful,
    00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00014 // GNU General Public License for more details.
    00015
    00016 // You should have received a copy of the GNU General Public License along
    00017 // with this library; see the file COPYING.  If not, write to the Free
    00018 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
    00019 // USA.
    00020
    00021 // As a special exception, you may use this file as part of a free software
    00022 // library without restriction.  Specifically, if other files instantiate
    00023 // templates or use macros or inline functions from this file, or you compile
    00024 // this file and link it with other files to produce an executable, this
    00025 // file does not by itself cause the resulting executable to be covered by
    00026 // the GNU General Public License.  This exception does not however
    00027 // invalidate any other reasons why the executable file might be covered by
    00028 // the GNU General Public License.
    00029
    00030 /** @file atomic_word.h
    00031  *  This file is a GNU extension to the Standard C++ Library.
    00032  */
    00033
    00034 #ifndef _GLIBCXX_ATOMIC_WORD_H
    00035 #define _GLIBCXX_ATOMIC_WORD_H  1
    00036
    00037 typedef int _Atomic_word;
    00038
    00039 // Define these two macros using the appropriate memory barrier for the target.
    00040 // The commented out versions below are the defaults.
    00041 // See ia64/atomic_word.h for an alternative approach.
    00042
    00043 // This one prevents loads from being hoisted across the barrier;
    00044 // in other words, this is a Load-Load acquire barrier.
    00045 // This is necessary iff TARGET_RELAXED_ORDERING is defined in tm.h.
    00046 // #define _GLIBCXX_READ_MEM_BARRIER __asm __volatile ("":::"memory")
    00047
    00048 // This one prevents stores from being sunk across the barrier; in other
    00049 // words, a Store-Store release barrier.
    00050 // #define _GLIBCXX_WRITE_MEM_BARRIER __asm __volatile ("":::"memory")
    00051
    00052 #endif