<?xml version="1.0" encoding="iso-8859-1"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <!-- console.qdoc --> <head> <title>A non-GUI example</title> <link href="classic.css" rel="stylesheet" type="text/css" /> </head> <body> <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr> <td align="left" valign="top" width="32"><img src="images/qt-logo.png" align="left" width="57" height="67" border="0" /></td> <td width="1"> </td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a></td> </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. ** ** 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." ** ****************************************************************************/</span> #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> <p /><address><hr /><div align="center"> <table width="100%" cellspacing="0" border="0"><tr class="address"> <td width="30%" align="left">Copyright © 2010 Nokia Corporation and/or its subsidiary(-ies)</td> <td width="40%" align="center"><a href="http://qt.nokia.com/doc/trademarks.html">Trademarks</a></td> <td width="30%" align="right"><div align="right">Qt Solutions</div></td> </tr></table></div></address></body> </html>