RE: Fwd: RE: [ROOT] bug in TCanvas TestBit ??

From: joe robe (joer00@yahoo.com)
Date: Sun Oct 07 2001 - 19:27:11 MEST


Dear Rene,

I guess I do not have do send you any codce examples
or more info since axels post should make it clear or
?

joe


> 
> Sorry to correct you, but the problem is not fixed
> yet. It's easy to imagine
> what's happening, although the problem is caused by
> a combination of TCanvas
> and TGWin32 code.
> 
> If a new canvas is created under Win, a message
> handler thread has to be
> created, too. This thread calls methods of TCanvas
> in case of e.g. mouse
> moves. The problem is that the windows message
> handler thread is created (in
> TGWin32) _before_ TCanvas initializes all its
> members. Valeri did move one
> initialization of a TCanvas member in front of the
> creation of the message
> handler thread, but only one - now it crashes at the
> next uninitialized
> member.
> 
> So we need a general fix here: FIRST initialize,
> THEN create the message
> handler. That's what the fix does I sent in some
> months ago. I've patched my
> private root version, it works perfectly for me, but
> as usually I won't bet
> what the side effects to Unix's TCanvas is... It
> might actually solve the
> TCanvas / thread problem observed on Unix, too, but
> who knows.
> 
> I hope that clarifies the problem.
> Cheers, Axel.
> 
> >
> > Rene Brun
> >
> >
> > >
> > > attached you find a message from axel neuman
> > > describing the same problem, so it seems you are
> aware
> > > of it.
> > >
> > > My current code might be to much stuff to send
> it, I
> > > will try to reproduce the behavior with less
> code.
> > >
> > > Undoubtly it ALWAYS crashes in debug mode ! In
> release
> > > mode I could avoid teh crahs now by IMMEDIATELY
> in the
> > > FIRTS LINE create the canvas. This might indeed
> work
> > > because in that 10 of a second I do not move the
> mouse
> > > over the screen.
> > >
> > > Joe
> > >
> > >
> > > Note: forwarded message attached.
> > >
> > >
> > >
> __________________________________________________
> > > Do You Yahoo!?
> > > NEW from Yahoo! GeoCities - quick and easy web
> site hosting,
> > just $8.95/month.
> > > http://geocities.yahoo.com/ps/info1
> >
> >
> 


__________________________________________________
Do You Yahoo!?
NEW from Yahoo! GeoCities - quick and easy web site hosting, just $8.95/month.
http://geocities.yahoo.com/ps/info1



This archive was generated by hypermail 2b29 : Tue Jan 01 2002 - 17:51:02 MET