Signals in QT (class taken from clementine's playlist manager header file).

playlistmanager.cpp

class PlaylistManagerInterface : public QObject {
  Q_OBJECT

public:
  PlaylistManagerInterface(Application* app, QObject* parent)
    : QObject(parent) {}
  // methods

public slots:
  virtual void Load(const QString& filename) = 0;
  virtual void SelectionChanged(const QItemSelection& selection) = 0;
  // more slots ...
  
signals:
  void PlaylistManagerInitialized();
  // more signals
  
};