Re: Debugging propagated events

[zahlenmeer gmx de]

I added some logic and after that I got a warning that there is a
mismatch between cairo_save and cairo_restore. So I fixed that and I got
it working. The cairo logic was faulty all the time but only some new
lines of code triggered that warning.
So I guess I was just lucky that I stopped debugging for a moment and
added those few lines.

On 11/29/16 03:13, Jim Charlton wrote:
> In Gtkmm (C++) you can overload the on_draw() function with your own. 
> This might give you a foothold in the on_draw() routine that is called
> after a redraw event occurs.  I guess in GTK you would have to connect a
> callback function to the "draw" signal.  Might help.??
>
> jim...
>
>
> On 2016-11-28 04:50 PM, zahlenmeer gmx de wrote:
> > This was one of the first things I did. Debug compilation option, debug
> > CFLAGS, no stripping - without a change. The backtrace only shows 3
> > lines, my draw function and two from libc.
> > The faulty address is not null. But the segfault happens after the
> > return where all local variables are no longer in scope, and the
> > addresses of the widget and the cairo context are valid.
> >
> > On 11/29/16 00:44, Alfonso Arbona Gimeno wrote:
> > > Hi,
> > >
> > > Why don't you link against the debug version of the library so that it
> > > shows you the complete stack?
> > > It will give you some extra clues on why the segfault is happening.
> > >
> > > Regards,
> > > Alfonso Arbona
> > >
> > > On November 29, 2016 6:17:05 AM GMT+09:00, zahlenmeer gmx de wrote:
> > >
> > >      For a custom widget I have a draw function. I do some drawing
> > > there and
> > >      when I am finished I return FALSE to let the parent draw.
> > > Immediately
> > >      after the return statement I get a segfault. gdb's backtrace
> > > only shows
> > >      my draw function and an address I cannot associate to any object.
> > >      Are there some general tricks how to debug such errors?
> > >
> > >      Kind regards
> > >     
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>
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