/****************************************************************************
**
** Copyright (C) 2011 Digia Plc
** All rights reserved.
** For any questions to Digia, please use contact form at http://qt.digia.com
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the 
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  
**
** If you have questions regarding the use of this file, please use
** contact form at http://qt.digia.com
** $QT_END_LICENSE$
** 
** Copyright (c) 2011 Nokia Corporation and/or its subsidiary(-ies).
**
****************************************************************************/

#ifndef QSYSTEMSEMAPHORE_H
#define QSYSTEMSEMAPHORE_H

#include <QtCore/qstring.h>
#include <QtCore/qscopedpointer.h>

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

QT_MODULE(Core)

#ifndef QT_NO_SYSTEMSEMAPHORE

class QSystemSemaphorePrivate;

class Q_CORE_EXPORT QSystemSemaphore
{

public:
    enum AccessMode
    {
        Open,
        Create
    };

    enum SystemSemaphoreError
    {
        NoError,
        PermissionDenied,
        KeyError,
        AlreadyExists,
        NotFound,
        OutOfResources,
        UnknownError
    };

    QSystemSemaphore(const QString &key, int initialValue = 0, AccessMode mode = Open);
    ~QSystemSemaphore();

    void setKey(const QString &key, int initialValue = 0, AccessMode mode = Open);
    QString key() const;

    bool acquire();
    bool release(int n = 1);

    SystemSemaphoreError error() const;
    QString errorString() const;

private:
    Q_DISABLE_COPY(QSystemSemaphore)
    QScopedPointer<QSystemSemaphorePrivate> d;
};

#endif // QT_NO_SYSTEMSEMAPHORE

QT_END_NAMESPACE

QT_END_HEADER

#endif // QSYSTEMSEMAPHORE_H

