Re: GTK Widget assertion problem

[David NeÄas <yeti physics muni cz>]

On Thu, Jun 10, 2010 at 01:31:33PM +0200, Michael T. wrote:
> In case anyone's interested I solved the problem with a little hack.
> I create the progress bar this way:
>
> progBar = gtk_progress_bar_new();  
> gtk_box_pack_start (GTK_BOX (vboxGr), GTK_PROGRESS_BAR(progBar), FALSE, FALSE, 0);
> gtk_widget_show (progBar));
> progressBarHack(progBar);
>
> the function progressBarHack() looks like this:
>
> void progressBarHack(GtkWidget* bar)
> {
>     progBar = bar; 
> }
>
> progBar is a global variable. I get an assertion error when I try to work with it outside the function 
> where the bar was created.
> When I use my hack, which does nothing except some pointer work, everything works fine.
> I don't know why the hack was needed because I've worked with several widgets with no problems at all. But 
> this thing works.

Hello, this all looks like utter voodoo.  You have probably a trivial
bug somewhere (elsewhere) in your code, maybe some
extern/static/initialization confusion?  Or you overwrite the stack and
calling progressBarHack() causes a change of the layout so that you
overwrite a less sensitive place now?   Anyway, it is recommended fix to
avoid global variables, they are evil, and externs are double-evil.  But
perhaps if you show a minimal *complete* example that exhibits the error
some will be able to help you.  Or, likely, you will find the root cause
while trying to extract the bad behaviour into a simple example...

Yeti