/****************************************************************************+
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**+
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** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).+
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** All rights reserved.+
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** Contact: Nokia Corporation (qt-info@nokia.com)+
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**+
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** This file is part of the QtGui module of the Qt Toolkit.+
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**+
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** $QT_BEGIN_LICENSE:LGPL$+
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** No Commercial Usage+
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** This file contains pre-release code and may not be distributed.+
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** You may use this file in accordance with the terms and conditions+
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** contained in the Technology Preview License Agreement accompanying+
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** this package.+
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**+
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** GNU Lesser General Public License Usage+
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** Alternatively, this file may be used under the terms of the GNU Lesser+
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** General Public License version 2.1 as published by the Free Software+
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** Foundation and appearing in the file LICENSE.LGPL included in the+
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** packaging of this file.  Please review the following information to+
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** ensure the GNU Lesser General Public License version 2.1 requirements+
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** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.+
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**+
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** In addition, as a special exception, Nokia gives you certain additional+
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** rights.  These rights are described in the Nokia Qt LGPL Exception+
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.+
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**+
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** If you have questions regarding the use of this file, please contact+
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** Nokia at qt-info@nokia.com.+
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**+
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**+
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**+
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**+
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**+
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**+
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**+
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**+
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** $QT_END_LICENSE$+
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**+
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****************************************************************************/+
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+
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#include "qwssharedmemory_p.h"+
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+
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#if !defined(QT_NO_QWS_MULTIPROCESS)+
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+
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#include <sys/shm.h>+
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+
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QT_BEGIN_NAMESPACE+
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+
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QWSSharedMemory::QWSSharedMemory()+
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    : shmBase(0), shmSize(0), character(0),  shmId(-1), key(-1)+
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{+
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}+
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+
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+
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QWSSharedMemory::~QWSSharedMemory()+
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{+
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    detach();+
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}+
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+
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/*+
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  man page says:+
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    On  Linux,  it is possible to attach a shared memory segment even if it+
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    is already marked to be deleted.  However, POSIX.1-2001 does not  spec-+
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    ify this behaviour and many other implementations do not support it.+
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*/+
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+
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bool QWSSharedMemory::create(int size)+
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{+
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    if (shmId != -1)+
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        detach();+
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    shmId = shmget(IPC_PRIVATE, size, IPC_CREAT|0600);+
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+
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    if (shmId == -1) {+
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#ifdef QT_SHM_DEBUG+
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        perror("QWSSharedMemory::create allocating shared memory");+
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        qWarning("Error allocating shared memory of size %d", size);+
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#endif+
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        return false;+
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    }+
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    shmBase = shmat(shmId,0,0);+
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    shmctl(shmId, IPC_RMID, 0);+
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    if (shmBase == (void*)-1) {+
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#ifdef QT_SHM_DEBUG+
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        perror("QWSSharedMemory::create attaching to shared memory");+
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        qWarning("Error attaching to shared memory id %d", shmId);+
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#endif+
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        shmBase = 0;+
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        return false;+
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    }+
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    return true;+
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}+
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+
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bool QWSSharedMemory::attach(int id)+
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{+
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    if (shmId == id)+
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        return id != -1;+
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    if (shmId != -1)+
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        detach();+
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+
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    shmBase = shmat(id,0,0);+
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    if (shmBase == (void*)-1) {+
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#ifdef QT_SHM_DEBUG+
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        perror("QWSSharedMemory::attach attaching to shared memory");+
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        qWarning("Error attaching to shared memory 0x%x of size %d",+
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                 id, size());+
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#endif+
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        shmBase = 0;+
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        return false;+
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    }+
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    shmId = id;+
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    return true;+
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}+
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+
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+
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void QWSSharedMemory::detach ()+
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{+
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    if (!shmBase)+
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        return;+
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    shmdt (shmBase);+
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    shmBase = 0;+
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    shmSize = 0;+
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    shmId = -1;+
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}+
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+
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void QWSSharedMemory::setPermissions (mode_t mode)+
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{+
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  struct shmid_ds shm;+
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  shmctl (shmId, IPC_STAT, &shm);+
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  shm.shm_perm.mode = mode;+
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  shmctl (shmId, IPC_SET, &shm);+
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}+
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+
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int QWSSharedMemory::size () const+
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{+
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    struct shmid_ds shm;+
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    shmctl (shmId, IPC_STAT, &shm);+
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    return shm.shm_segsz;+
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}+
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+
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+
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// old API+
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+
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+
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+
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QWSSharedMemory::QWSSharedMemory (int size, const QString &filename, char c)+
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{+
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  shmSize = size;+
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  shmFile = filename;+
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  shmBase = 0;+
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  shmId = -1;+
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  character = c;+
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  key = ftok (shmFile.toLatin1().constData(), c);+
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}+
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+
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+
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+
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bool QWSSharedMemory::create ()+
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{+
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  shmId = shmget (key, shmSize, IPC_CREAT | 0666);+
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  return (shmId != -1);+
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}+
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+
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void QWSSharedMemory::destroy ()+
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{+
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    if (shmId != -1)+
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        shmctl(shmId, IPC_RMID, 0);+
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}+
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+
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bool QWSSharedMemory::attach ()+
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{+
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  if (shmId == -1)+
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    shmId = shmget (key, shmSize, 0);+
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+
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  shmBase = shmat (shmId, 0, 0);+
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  if ((long)shmBase == -1)+
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      shmBase = 0;+
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+
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  return (long)shmBase != 0;+
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}+
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+
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+
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QT_END_NAMESPACE+
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+
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#endif // QT_NO_QWS_MULTIPROCESS+
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