cation.html#sendMessage">sendMessage</a>() fails, that is an indication that the running instance is frozen.</p>
<p>Here's an example that shows how to convert an existing application to use QtSingleApplication. It is very simple and does not make use of all QtSingleApplication's functionality (see the examples for that).</p>
<pre><span class="comment"> // Original</span>
 int main(int argc, char **argv)
 {
     QApplication app(argc, argv);

     MyMainWidget mmw;
     mmw.show();
     return app.exec();
 