+ /*
+ -- ** -- S I G N A L S -------------------------------------------------------
+ */
+
+private:
+
+ sigc::signal<void> signal_progress_;
+
+ /*
+ -- ** -- S I G N A L I N T E R F A C E -------------------------------------
+ */
+
+public:
+
+ sigc::signal<void>& signal_progress() { return signal_progress_; }
+
+ /*
+ -- ** -- C O N S T R U C T O R S ---------------------------------------------
+ */
+
+public: