QT plugins: a plugin that is a GUI

[trallallero]

I don't understand how to create an empy application that only loads a plugin that is a GUI itself.
I cannot make it work ...

Actually I have a main.cpp that creates and executes a QApplication

int main(int argc, char *argv[])
{
	MainApp app(argc, argv);
	return app.exec();
}

int main(int argc, char *argv[])
{
	MainApp app(argc, argv);
	return app.exec();
}

To copy to clipboard, switch view to plain text mode 

class MainApp : public QApplication
{
	Q_OBJECT
 
	public:
		MainApp(int &argc, char **argv);
		~MainApp();
 
	private:
		void loadPlugins();
 
		QDir         pluginsDir;
		QStringList  pluginFileNames;
}

class MainApp : public QApplication
{
	Q_OBJECT

	public:
		MainApp(int &argc, char **argv);
		~MainApp();

	private:
		void loadPlugins();

		QDir         pluginsDir;
		QStringList  pluginFileNames;
}

To copy to clipboard, switch view to plain text mode 

when MainApp is created it calls loadPlugins:

MainApp::MainApp(int &argc, char **argv) :
   QApplication(argc, argv)
{
   loadPlugins();
}

MainApp::MainApp(int &argc, char **argv) :
   QApplication(argc, argv)
{
   loadPlugins();
}

To copy to clipboard, switch view to plain text mode 

QPluginLoader loader(..) fails as I get:

ERROR !!! loader.isLoaded(): <0> - loader.errorString(): <Unknown error>

Does anybody know something about it ?
Thanks.