[XForms] mouse wheel in browser crashes whole app

Michal Szymanski msz at astrouw.edu.pl
Sun Mar 13 23:27:16 EST 2005

> > Howerver, quite often, possibly
> > (although I am not sure) when the browser has many lines and I rotate
> > the wheel fast, the whole application crashes badly.
> jason cipriani said:
> > It's weird that it crashes, though. When you say it only happens in
> > browsers with a lot of items, how many items is "a lot"?
> I'm with Jason on this one. I'd bet its a code bug in your app.. I use
> big browser lists and I had exactly the same symptom. I spent a while 
> suspecting xforms too - but it was me ;-(
> If it helps at all, in my case, the root cause was it was a callback
> being called with no line selected in the browser. I didn't check,
> and ended up dereferenced a wild pointer and core-dumped.

It well might be a code bug. As I said before, the crashes are random
and my guess to link them to the number of lines in the browser and/or
the speed of rotating the mice wheel may be wrong. Unfortunately it is a
kind of "production" application, controlling real hardware, so I cannot
make too many experiments.

"A lot of lines" may be several thousand. The browser gets the messages
from the telescope control system, I would estimate this to 1600-1800
lines per night and the program can run several weeks if everything is
going fine.

As for the "callback" suggestion: it is a FL_NORMAL_BROWSER, so AFAIK
there should be no interaction requiring callbacks. Just the scrolling.

I managed to disable mouse buttons 4 & 5 (wheel) for the browser using

regards, Michal.

  Michal Szymanski (msz at astrouw dot edu dot pl)
  Warsaw University Observatory, Warszawa, POLAND

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