ncbiatomic.cpp

ncbi源码

/*
 * ===========================================================================
 * PRODUCTION $Log: ncbiatomic.cpp,v $
 * PRODUCTION Revision 1000.1  2004/06/01 19:08:51  gouriano
 * PRODUCTION PRODUCTION: UPGRADED [GCC34_MSVC7] Dev-tree R1.2
 * PRODUCTION
 * ===========================================================================
 */

/*  $Id: ncbiatomic.cpp,v 1000.1 2004/06/01 19:08:51 gouriano Exp $
 * ===========================================================================
 *
 *                            PUBLIC DOMAIN NOTICE
 *               National Center for Biotechnology Information
 *
 *  This software/database is a "United States Government Work" under the
 *  terms of the United States Copyright Act.  It was written as part of
 *  the author's official duties as a United States Government employee and
 *  thus cannot be copyrighted.  This software/database is freely available
 *  to the public for use. The National Library of Medicine and the U.S.
 *  Government have not placed any restriction on its use or reproduction.
 *
 *  Although all reasonable efforts have been taken to ensure the accuracy
 *  and reliability of the software and data, the NLM and the U.S.
 *  Government do not and cannot warrant the performance or results that
 *  may be obtained by using this software or data. The NLM and the U.S.
 *  Government disclaim all warranties, express or implied, including
 *  warranties of performance, merchantability or fitness for any particular
 *  purpose.
 *
 *  Please cite the author in any work or product based on this material.
 *
 * ===========================================================================
 *
 * Author:  Aaron Ucko
 *
 * File Description:
 *      SwapPointers     -- atomic pointer swap operation
 *
 */


#include <ncbi_pch.hpp>
#include <corelib/ncbiatomic.hpp>

#ifdef NCBI_SLOW_ATOMIC_SWAP

#include <corelib/ncbimtx.hpp>

BEGIN_NCBI_SCOPE

DEFINE_STATIC_FAST_MUTEX(sx_AtomicPointerMutex);

void* x_SwapPointers(void * volatile * nv_loc, void* new_value)
{
    CFastMutexGuard LOCK(sx_AtomicPointerMutex);
    void* old_value = *nv_loc;
    *nv_loc = new_value;
    return old_value;
}

END_NCBI_SCOPE

#endif//NCBI_SLOW_ATOMIC_SWAP

/*
 * ===========================================================================
 * $Log: ncbiatomic.cpp,v $
 * Revision 1000.1  2004/06/01 19:08:51  gouriano
 * PRODUCTION: UPGRADED [GCC34_MSVC7] Dev-tree R1.2
 *
 * Revision 1.2  2004/05/14 13:59:27  gorelenk
 * Added include of ncbi_pch.hpp
 *
 * Revision 1.1  2003/09/17 15:20:46  vasilche
 * Moved atomic counter swap functions to separate file.
 * Added CRef<>::AtomicResetFrom(), CRef<>::AtomicReleaseTo() methods.
 *
 * Revision 1.28  2003/06/27 17:28:08  ucko
 * +SwapPointers
 * ===========================================================================
 */