As what Ian also mentioned, FLTK by design assumes that a single thread is accessing the GUI at a time. For instance there is a single graphics state (like current transformation matrix, current font, color) and other globals - accessing/changing them (eg during redraw) in parallel would cause a mess. You could get away by having some global "GUI lock" (which FLTK already has) but then you loose all the multi-threading advantage.
You can run as many threads as you wish (eg each window can have additional background thread) for calculation-intensive tasks which do not access GUI directly and once done, send the results to the particular window/main-thread (with proper synchronisation/locking) to visualise the results. R. PS: This question would fit better in fltk.general forum _______________________________________________ fltk-dev mailing list fltk-dev@easysw.com http://lists.easysw.com/mailman/listinfo/fltk-dev
