+
+ /*!
+ * \brief Block message handler.
+ *
+ * \param msg Arbitrary message encapsulated as pmt::pmt_t
+ *
+ * This function is called by the runtime system whenever there are
+ * messages in its queue. Blocks should override this to receive
+ * messages; the default behavior is to drop them on the floor.
+ */
+ virtual void handle_msg(pmt::pmt_t msg) { };