Re: Catching Figure close button - callbacks not running?

[Pavel Hofman]

> Callback functions are written in m-code, as such they must be 
> interpreted and are thus executed in the "interpreter" (or "worker") 
> thread. The "main" (or "GUI")  thread is the one in which GUI objects 
> (as figures) live.

Thanks for the explanation. I am slowly getting to understand octave 
details :-)

> None of those make the interpreter idle: until "pause" or "zmq_poll" 
> have returned, the interpreter is busy. The difference is that the 
> "pause" explicitly calls process_events (only once in Octave 4.4, every 
> 100ms in the soon released Octave 5) while I guess "zmq_poll" doesn't.

That  explains why Tony's callbacks are processed (pause) while mine are 
not (zmq_poll with timeout).

> If you want to obtain the same kind of behavior you could do something like
>
> /havedata = false;/
> /while (! havedata)/
> /havedata/ *=* /zmq_poll (sock, 100);/
> /  drawnow ();/
> /endwhile/

Thanks, I will explicitely call drawnow in the poll loop then.

> I don't understand your use case, but anyway, as stated above, callback 
> functions will always end up being executed in the "interpreter" (not 
> "main") thread, where your program is executed.

IMO the important information (which I was not sure about) is "all code 
in one thread". Thanks for enlightenment.

Do you think it would be technically possible to run the callbacks in 
another thread using parallel package, allowing the callbacks to call 
pause() while the zmq_poll loop could cycle unaffected? It would require 
all the threads sharing/having access to global variables. I do not know 
if the parallel package allows this kind of computing.

Thanks a lot,

Pavel.