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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 1.0, 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 are unsure which license is appropriate for your use, please
+** contact the sales department at http://qt.nokia.com/contact.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+ \page qt4-threads.html
+ \title Thread Support in Qt 4
+
+ \contentspage {What's New in Qt 4}{Home}
+ \previouspage The Qt 4 Style API
+
+ Qt 4 makes it easier than ever to write multithreaded
+ applications. More classes have been made usable from non-GUI
+ threads, and the signals and slots mechanism can now be used to
+ communicate between threads.
+
+ \section1 General Overview
+
+ QThread now inherits QObject. It emits signals to indicate that
+ the thread started or finished executing, and provides a few
+ slots as well.
+
+ Each thread can now have its own event loop. The initial thread
+ starts its event loops using QCoreApplication::exec(); other
+ threads can start an event loop using QThread::exec(). Like
+ QCoreApplication, QThread also provides an
+ \l{QThread::exit()}{exit(int)} function and a
+ \l{QThread::quit()}{quit()} slot.
+
+ An event loop in a thread makes it possible for the thread to use
+ certain non-GUI Qt classes that require the presence of an event
+ loop (such as QTimer, QTcpSocket, and QProcess). It also makes it
+ possible to connect signals from any threads to slots of a
+ specific thread. When a signal is emitted, the slot isn't called
+ immediately; instead, it is invoked when control returns to the
+ event loop of the thread to which the object belongs. The slot is
+ executed in the thread where the receiver object lives. See
+ QObject::connect() for details.
+
+ Qt 4 also introduces a new synchronization class: QReadWriteLock.
+ It is similar to QMutex, except that it distinguishes between
+ "read" and "write" access to shared data and allows multiple
+ readers to access the data simultaneously. Using QReadWriteLock
+ instead of QMutex when it is possible can make multithreaded
+ programs more concurrent.
+
+ Since Qt 4, \l{implicitly shared} classes can safely be copied
+ across threads, like any other value classes. They are fully
+ reentrant. This is implemented using atomic reference counting
+ operations, which are implemented in assembly language for the
+ different platforms supported by Qt. Atomic reference counting is
+ very fast, much faster than using a mutex.
+
+ See \l{Thread Support in Qt} for more information.
+
+ \section1 Comparison with Qt 3
+
+ Earlier versions of Qt offered an option to build the library
+ without thread support. In Qt 4, threads are always enabled.
+
+ Qt 3 had a class called \c QDeepCopy that you could use to take a
+ deep copy of an implicitly shared object. In Qt 4, the atomic
+ reference counting makes this class superfluous.
+*/