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Diffstat (limited to 'doc/src/snippets/qelapsedtimer/main.cpp')
-rw-r--r-- | doc/src/snippets/qelapsedtimer/main.cpp | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/doc/src/snippets/qelapsedtimer/main.cpp b/doc/src/snippets/qelapsedtimer/main.cpp new file mode 100644 index 0000000..9d0421f --- /dev/null +++ b/doc/src/snippets/qelapsedtimer/main.cpp @@ -0,0 +1,112 @@ +/**************************************************************************** +** +** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the QtNetwork module 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 Technology Preview License Agreement accompanying +** this package. +** +** 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. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ +#include <QtCore> + +void slowOperation1() +{ + static char buf[256]; + for (int i = 0; i < (1<<20); ++i) + buf[i % sizeof buf] = i; +} + +void slowOperation2(int) { slowOperation1(); } + +void startExample() +{ +//![0] + QElapsedTimer timer; + timer.start(); + + slowOperation1(); + + qDebug() << "The slow operation took" << timer.elapsed() << "milliseconds"; +//![0] +} + +//![1] +void executeSlowOperations(int timeout) +{ + QElapsedTimer timer; + timer.start(); + slowOperation1(); + + int remainingTime = timeout - timer.elapsed(); + if (remainingTime > 0) + slowOperation2(remainingTime); +} +//![1] + +//![2] +void executeOperationsForTime(int ms) +{ + QElapsedTimer timer; + timer.start(); + + while (!timer.hasExpired(ms)) + slowOperation1(); +} +//![2] + +int restartExample() +{ +//![3] + QElapsedTimer timer; + + int count = 1; + timer.start(); + do { + count *= 2; + slowOperation2(count); + } while (timer.restart() < 250); + + return count; +//![3] +} + +int main(int argc, char **argv) +{ + QCoreApplication app(argc, argv); + + startExample(); + restartExample(); + executeSlowOperations(5); + executeOperationsForTime(5); +} |