[wxPython-users] Some wxpython questions about gtk wxPython Unicode 2.8.1.1

[Robin Dunn]

Franz Steinhäusler wrote:
> Hello NG,
> 

I just answered most of this on wx-dev, will do so again here for the 
archive's sake.


> Two questions:
> 
>   1) If a "Segmentation fault (core dumped)" happend, it is a crash, isn't it?

Yes, more or less.  It is the program double-checking certain things 
itself and aborting itself if the condition fails.

>   
>       So after that assertions, a segmentation fault follows.
>         
>         ** (python:5936): CRITICAL **: gail_menu_item_ref_child: assertion `(i >= 0)' failed
>           dann kommt segmentation fault
> 
>         wie segmentatoin fault, genauere info, was verursacth dies? (wxwidgets forum, wxpython mailing list, wxwidgets newsgroup)
> 
>           ** (python:12488): CRITICAL **: gail_menu_item_ref_child: assertion `(i >= 0)' failed
>           Segmentation fault (core dumped)
> 
>           ** (python:12542): CRITICAL **: gail_menu_item_ref_child: assertion `(i >= 0)' failed
>           Segmentation fault (core dumped)
> 
>       
>       a) How can I trace back, what a segmentation fault caused?

If there is enough debug info present then loading the core file into 
gdb and running backtrace may give some clues.


>       
>       b) What does that mean (gail_menu_item_ref_child: assertion `(i >= 0)' failed)?

In the gail_menu_item_ref_child function  there is an assert statement 
checking that  the variable i is >=0, but it is failing.  I assume from 
the function name that it is a reference counting error, and that 
something is getting decref'd too many times.


>       
>       c) What do the numbers 12542 and 12488? Could this numbers be useful?

No, they are just the process ID.


>       
>       d) What is the best way to debug or isolate this to a certatin piece of code this?

Go through a few iterations of disabling portions of your code and 
retesting until you are able to narrow down the thing that is causing 
the problem.

> 
>   2) GTK Accessibility Module initialized: 
>       Is this message necessary?

Not sure.  Is it being printed to the console?  It is probably coming 
from gail itself, so it would be up to gail to suppress it.

-- 
Robin Dunn
Software Craftsman
http://wxPython.org  Java give you jitters?  Relax with wxPython!