+/**
+ * Function to register a hook function that will be called by the main window
+ * when the time span of the traceset is updated.
+ *
+ * This register function is typically called by the constructor of the viewer.
+ *
+ * @param tab the tab the viewer belongs to.
+ * @param hook hook that sould be called by the main window when the time
+ * interval changes.
+ * @param hook_data hook data associated with the hook function. It will
+ * be typically a pointer to the viewer's data structure.
+ */
+void lttvwindow_register_timespan_notify(Tab *tab,
+ LttvHook hook,
+ gpointer hook_data);
+
+/**
+ * Function to unregister the time_span notification hook.
+ *
+ * This unregister function is typically called by the destructor of the viewer.
+ *
+ * @param tab the tab the viewer belongs to.
+ * @param hook hook that sould be called by the main window when the time
+ * interval changes.
+ * @param hook_data hook data associated with the hook function. It will
+ * be typically a pointer to the viewer's data structure.
+ */
+void lttvwindow_unregister_timespan_notify(Tab *tab,
+ LttvHook hook,
+ gpointer hook_data);