Re: gtk_tree_model_get_iter segfault in on_row_activated

[Christopher Backhouse <cjbackhouse gmail com>]

You are both right - it now works fine. Thanks for pointing out what was 
right under my nose. I do honestly know what I am doing with pointers - 
I think this is the effects of code written at 2 in the morning and then 
seeing what should have been there upon trying to debug it.
"All the parameters I pass are at least existing" should have been a 
hint as to where the trouble lay....
Now I'm embarrassed - I think I will crawl away and hide for a bit (at 
least with my faith in GTK restored though)


blythe2 tcnj edu wrote:
> Iter needs to be an actual object, not just a pointer.  You are *creating*
> a n iterator, then passing it by reference to be filled.  As your code
> stands now, you're passing an uninitialized pointer to be written to,
> which of course crashes.  Try the following:
>
> void on_row_activated(GtkTreeView* tree_view,GtkTreePath*
> path,GtkTreeViewColumn* column,gpointer user_data)
> {
>         std::cout<<"path was "<<gtk_tree_path_to_string(path)<<"\n";
>         GtkTreeModel* model=gtk_tree_view_get_model(tree_view);
>         if(model!=NULL)
>                 std::cout<<"got the model OK\n";
>         else
>                 std::cout<<"failed to get the model\n";
>         std::cout<<"trying to get the iter\n";
>         GtkTreeIter iter;
>         if(gtk_tree_model_get_iter(model,&iter,path)==TRUE)
>                 std::cout<<"got the iter ok\n";
>         else
>                 std::cout<<"didn't get the iter\n";
> }
>
>
> That should work better.  Hope that helps!
>
> -Nate
>
>
>   
> > I have connected to the row activated signal and want to handle it - so
> > I am doing this:
> >
> > void on_row_activated(GtkTreeView* tree_view,GtkTreePath*
> > path,GtkTreeViewColumn* column,gpointer user_data)
> > {
> >         std::cout<<"path was "<<gtk_tree_path_to_string(path)<<"\n";
> >         GtkTreeModel* model=gtk_tree_view_get_model(tree_view);
> >         if(model!=NULL)
> >                 std::cout<<"got the model OK\n";
> >         else
> >                 std::cout<<"failed to get the model\n";
> >         std::cout<<"trying to get the iter\n";
> >         GtkTreeIter* iter;
> >         if(gtk_tree_model_get_iter(model,iter,path)==TRUE)
> >                 std::cout<<"got the iter ok\n";
> >         else
> >                 std::cout<<"didn't get the iter\n";
> > }
> >
> > upon double-clicking an item in the list output looks something like (in
> > this case the 4th entry)
> >
> > path was 3
> > got the model OK
> > trying to get the iter
> > Segmentation fault
> >
> > although bizarrely it very occasionally works fine.
> >
> > Any ideas? It's a bit impolite to segfault when all the parameters I
> > pass are at least existing
> > _______________________________________________
> > gtk-app-devel-list mailing list
> > gtk-app-devel-list gnome org
> > http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
> >
> >     
>
>
>
>