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<?xml version="1.0" encoding="iso-8859-1"?>
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<title>A non-GUI example</title>
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</tr></table><h1 class="title">A non-GUI example<br /><span class="subtitle"></span>
</h1>
<p>This example shows how to use the single-application functionality in a console application. It does not require the <tt>QtGui</tt> library at all.</p>
<p>The only differences from the GUI application usage demonstrated in the other examples are:</p>
<p>1) The <tt>.pro</tt> file should include <tt>qtsinglecoreapplication.pri</tt> instead of <tt>qtsingleapplication.pri</tt></p>
<p>2) The class name is <tt>QtSingleCoreApplication</tt> instead of <tt>QtSingleApplication</tt>.</p>
<p>3) No calls are made regarding window activation, for obvious reasons.</p>
<p>console.pro:</p>
<pre> TEMPLATE = app
CONFIG += console
SOURCES += main.cpp
include(../../src/qtsinglecoreapplication.pri)
QT -= gui</pre>
<p>main.cpp:</p>
<pre><span class="comment"> /****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the Qt Solutions component.
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**
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** 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,
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#include "qtsinglecoreapplication.h"
#include <QtCore/QDebug>
void report(const QString& msg)
{
qDebug("[%i] %s", (int)QCoreApplication::applicationPid(), qPrintable(msg));
}
class MainClass : public QObject
{
Q_OBJECT
public:
MainClass()
: QObject()
{}
public slots:
void handleMessage(const QString& message)
{
report( "Message received: \"" + message + "\"");
}
};
int main(int argc, char **argv)
{
report("Starting up");
QtSingleCoreApplication app(argc, argv);
if (app.isRunning()) {
QString msg(QString("Hi master, I am %1.").arg(QCoreApplication::applicationPid()));
bool sentok = app.sendMessage(msg, 2000);
QString rep("Another instance is running, so I will exit.");
rep += sentok ? " Message sent ok." : " Message sending failed; the other instance may be frozen.";
report(rep);
return 0;
} else {
report("No other instance is running; so I will.");
MainClass mainObj;
QObject::connect(&app, SIGNAL(messageReceived(const QString&)),
&mainObj, SLOT(handleMessage(const QString&)));
return app.exec();
}
}
#include "main.moc"</pre>
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