| 1 | /****************************************************************************
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| 2 | **
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| 3 | ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
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| 4 | ** All rights reserved.
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| 7 | ** This file is part of the documentation of the Qt Toolkit.
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| 9 | ** $QT_BEGIN_LICENSE:LGPL$
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| 16 | ** GNU Lesser General Public License Usage
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| 26 | ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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| 28 | ** GNU General Public License Usage
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| 30 | ** General Public License version 3.0 as published by the Free Software
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| 40 | ****************************************************************************/
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| 41 |
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| 42 | /*!
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| 43 | \page timers.html
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| 44 | \title Timers
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| 45 | \brief How to use timers in your application.
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| 46 |
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| 47 | \ingroup best-practices
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| 48 |
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| 49 | QObject, the base class of all Qt objects, provides the basic
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| 50 | timer support in Qt. With QObject::startTimer(), you start a
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| 51 | timer with an interval in milliseconds as argument. The function
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| 52 | returns a unique integer timer ID. The timer will now fire at
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| 53 | regular intervals until you explicitly call QObject::killTimer()
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| 54 | with the timer ID.
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| 55 |
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| 56 | For this mechanism to work, the application must run in an event
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| 57 | loop. You start an event loop with QApplication::exec(). When a
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| 58 | timer fires, the application sends a QTimerEvent, and the flow of
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| 59 | control leaves the event loop until the timer event is processed.
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| 60 | This implies that a timer cannot fire while your application is
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| 61 | busy doing something else. In other words: the accuracy of timers
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| 62 | depends on the granularity of your application.
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| 63 |
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| 64 | In multithreaded applications, you can use the timer mechanism in
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| 65 | any thread that has an event loop. To start an event loop from a
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| 66 | non-GUI thread, use QThread::exec(). Qt uses the object's
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