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Diffstat (limited to 'doc/src/snippets/qelapsedtimer/main.cpp')
-rw-r--r-- | doc/src/snippets/qelapsedtimer/main.cpp | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/doc/src/snippets/qelapsedtimer/main.cpp b/doc/src/snippets/qelapsedtimer/main.cpp new file mode 100644 index 0000000000..3e5b520f57 --- /dev/null +++ b/doc/src/snippets/qelapsedtimer/main.cpp @@ -0,0 +1,111 @@ +/**************************************************************************** +** +** Copyright (C) 2011 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. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor +** the names of its contributors may be used to endorse or promote +** products derived from this software without specific prior written +** permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** $QT_END_LICENSE$ +** +****************************************************************************/ +#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); +} |