* @param end end time of the traceset.
*/
-TimeInterval *lttvwindow_viewer_get_time_span(MainWindow *main_win);
+const TimeInterval *lttvwindow_viewer_get_time_span(MainWindow *main_win);
/**
* Function to get the current time window of the current tab.
* @param time_interval a pointer where time interval will be stored.
*/
-TimeWindow *lttvwindow_viewer_get_time_window(MainWindow *main_win);
+const TimeWindow *lttvwindow_viewer_get_time_window(MainWindow *main_win);
/**
* @param time a pointer where time will be stored.
*/
-LttTime *lttvwindow_viewer_get_current_time(MainWindow *main_win);
+const LttTime *lttvwindow_viewer_get_current_time(MainWindow *main_win);
/**
* Function to get the traceset from the current tab.
* @param traceset a pointer to a traceset.
*/
-LttvTraceset *lttvwindow_viewer_get_traceset(MainWindow *main_win);
+const LttvTraceset *lttvwindow_viewer_get_traceset(MainWindow *main_win);
/**
* @param filter, a pointer to a filter.
*/
-lttv_filter *lttvwindow_viewer_get_filter(MainWindow *main_win);
+const lttv_filter *lttvwindow_viewer_get_filter(MainWindow *main_win);
/**