AirTV-Qt/qtsingleapplication/doc/html/qtsinglecoreapplication-example-console.html

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  15 </tr></table><h1 class="title">A non-GUI example<br /><span class="subtitle"></span>
  16 </h1>
  17 <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>
  18 <p>The only differences from the GUI application usage demonstrated in the other examples are:</p>
  19 <p>1) The <tt>.pro</tt> file should include <tt>qtsinglecoreapplication.pri</tt> instead of <tt>qtsingleapplication.pri</tt></p>
  20 <p>2) The class name is <tt>QtSingleCoreApplication</tt> instead of <tt>QtSingleApplication</tt>.</p>
  21 <p>3) No calls are made regarding window activation, for obvious reasons.</p>
  22 <p>console.pro:</p>
  23 <pre> TEMPLATE   = app
  24  CONFIG    += console
  25  SOURCES   += main.cpp
  26  include(../../src/qtsinglecoreapplication.pri)
  27  QT -= gui</pre>
  28 <p>main.cpp:</p>
  29 <pre><span class="comment"> /****************************************************************************
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  67
  68  #include &quot;qtsinglecoreapplication.h&quot;
  69  #include &lt;QtCore/QDebug&gt;
  70
  71  void report(const QString&amp; msg)
  72  {
  73      qDebug(&quot;[%i] %s&quot;, (int)QCoreApplication::applicationPid(), qPrintable(msg));
  74  }
  75
  76  class MainClass : public QObject
  77  {
  78      Q_OBJECT
  79  public:
  80      MainClass()
  81          : QObject()
  82          {}
  83
  84  public slots:
  85      void handleMessage(const QString&amp; message)
  86          {
  87              report( &quot;Message received: \&quot;&quot; + message + &quot;\&quot;&quot;);
  88          }
  89  };
  90
  91  int main(int argc, char **argv)
  92  {
  93      report(&quot;Starting up&quot;);
  94
  95      QtSingleCoreApplication app(argc, argv);
  96
  97      if (app.isRunning()) {
  98          QString msg(QString(&quot;Hi master, I am %1.&quot;).arg(QCoreApplication::applicationPid()));
  99          bool sentok = app.sendMessage(msg, 2000);
 100          QString rep(&quot;Another instance is running, so I will exit.&quot;);
 101          rep += sentok ? &quot; Message sent ok.&quot; : &quot; Message sending failed; the other instance may be frozen.&quot;;
 102          report(rep);
 103          return 0;
 104      } else {
 105          report(&quot;No other instance is running; so I will.&quot;);
 106          MainClass mainObj;
 107          QObject::connect(&amp;app, SIGNAL(messageReceived(const QString&amp;)),
 108                           &amp;mainObj, SLOT(handleMessage(const QString&amp;)));
 109          return app.exec();
 110      }
 111  }
 112
 113  #include &quot;main.moc&quot;</pre>
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