Re: [ROOT] ROOT/QtROOT within a multithreaded Qt application

From: Valeri Fine (fine@bnl.gov)
Date: Fri Jan 04 2002 - 22:16:48 MET


> 
> The original Qt application (CSF) runs fine without adding any of the ROOT
> stuff, and I do not call any Qt functions in my added code... just ROOT (and
> ROOT definitely does not call any Qt functions).
> 
> So the answer to your question, Valeri, is "yes, I have paid attention". But
> as I mentioned in the section you quoted, creating Qt widgets/dialogs from
> the simulation thread *does* work. It is TCanvas (specifically, displaying a
> TCanvas created in the simulation thread) that causes the program to segv.
> 

 Ok,
 Let me ask you another way.

 Qt GUI thread and the thread you make call to TCanvas (to  X11 in fact) 
 from are one and the same  or they are different? My guess they are different.

  Valeri

> Tony
> 
> -----Original Message-----
> From: Valeri Fine [mailto:fine@bnl.gov]
> Sent: Friday, January 04, 2002 14:46
> To: Colley, Tony; roottalk@pcroot.cern.ch
> Subject: Re: [ROOT] ROOT/QtROOT within a multithreaded Qt application
> 
> 
> > I **am** able to create a popup window using only Qt widgets from the
> > simulation thread, so it appears that my Linux, X11R6 and Qt are properly
> > setup to support threads. I would rather not have to rewrite ROOT to use
> > only Qt widgets.
> > 
> > I have looked at the Qt document "Thread Support in Qt", and at the
> Threads
> > chapter in the ROOT Users Guide, and I have looked at the roottalk
> messages
> > that were found by searching the ROOT website. I have also read through
> > http://go4.gsi.de/Threads/tthread.htm (where item 1.2.4 seems to indicate
> > that there is no hope). I may have missed something, of course, so feel
> free
> > to call me whatever names you prefer as long as you also clearly point me
> > wherever the "blatantly obvious solution" is documented.
> 
>   Have you paid your attention some Qt function can be called from the 
>   Qt GUI thread ONLY ?
> 
> > 
> > Any other helpful hints, suggestions, or fixes would also be appreciated.
> > 
> > Tony Colley
> > 
> > ITT Industries A/CD
> > Fort Wayne, IN  USA
> > Tony.Colley@itt.com
> 
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