source: trunk/src/corelib/tools/qscopedpointer.cpp@ 890

/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation ([email protected])
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** 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 Nokia.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you have questions regarding the use of this file, please contact
** Nokia at [email protected].
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qscopedpointer.h"

QT_BEGIN_NAMESPACE

/*!
    \class QScopedPointer
    \brief The QScopedPointer class stores a pointer to a dynamically allocated object, and deletes it upon destruction.
    \since 4.6
    \reentrant
    \ingroup misc

    Managing heap allocated objects manually is hard and error prone, with the
    common result that code leaks memory and is hard to maintain.
    QScopedPointer is a small utility class that heavily simplifies this by
    assigning stack-based memory ownership to heap allocations, more generally
    called resource acquisition is initialization(RAII).

    QScopedPointer guarantees that the object pointed to will get deleted when
    the current scope disappears.

    Consider this function which does heap allocations, and have various exit points:

    \snippet doc/src/snippets/code/src_corelib_tools_qscopedpointer.cpp 0

    It's encumbered by the manual delete calls. With QScopedPointer, the code
    can be simplified to:

    \snippet doc/src/snippets/code/src_corelib_tools_qscopedpointer.cpp 1

    The code the compiler generates for QScopedPointer is the same as when
    writing it manually. Code that makes use of \a delete are candidates for
    QScopedPointer usage (and if not, possibly another type of smart pointer
    such as QSharedPointer). QScopedPointer intentionally has no copy
    constructor or assignment operator, such that ownership and lifetime is
    clearly communicated.

    The const qualification on a regular C++ pointer can also be expressed with
    a QScopedPointer:

    \snippet doc/src/snippets/code/src_corelib_tools_qscopedpointer.cpp 2

    \section1 Custom cleanup handlers