Re: where is error?

[Paul Davis <pjdavis engineering uiowa edu>]

I've been following this thread a bit and I did some checking. I may be 
way off base here but after doing some checking I think that RadioGroup 
wasn't meant to be overridden.

RadioAction::RadioAction(Group& group, const Glib::ustring& name, const 
Gtk::StockID& stock_id, const Glib::ustring& label, const Glib::ustring& 
tooltip)
:
 Glib::ObjectBase(0), //Mark this class as gtkmmproc-generated, rather 
than a custom class, to allow vfunc optimisations.

I found this bit in the constructor in radioaction.cc line 35 of version 
2.6.something

I have very little experience with the gtk/gnome underpinnings but this 
was a red flag so I thought I'd mention it.

It is quite weird.

...

A thought occurred to me. I dunno why or how but this works:

The important part seems to be theL

Glib::ObjectBase(0)

Perhaps Murray can indulge us all.  It seems like one of those C++ 
gotchyas from where I'm sitting. Granted thats post-alcohol, but still...

#include <gtkmm.h>

 class Radio_action : public Gtk::RadioAction
 {
 public:

   Radio_action (Gtk::RadioButtonGroup& group)
   :
       Glib::ObjectBase(0),
       Gtk::RadioAction ()
   {
       set_group( group ) ;
   }

   static
   Glib::RefPtr<Gtk::RadioAction> Radio_action::create( 
Gtk::RadioButtonGroup& group)
   {
       return Glib::RefPtr<Radio_action>( new Radio_action(group) );
   }
 };


int
main (int argc, char** argv)
{
 Gtk::Main  main (argc, argv);

 Gtk::RadioButtonGroup  test_group;

#if 1
 // This segfaults.
 Radio_action::create (test_group);
#else
 Gtk::RadioAction::create (test_group, "test");
#endif

 return 0;
}

I sure could go into whether this is a library or a user thing. But I 
have got to say, reading the source sure helps quite a bit.

Paul Pogonyshev wrote:

> Murray Cumming wrote:
>  
>
> > It should of course be
> >
> > Glib::RefPtr<Radio_action> Radio_action::create(RadioActionGroup& group)
> > {
> >  return Glib::RefPtr<Radio_action>( new Radio_action(group) );
> > }
> >
> > Again, I have no idea whether this will stop your segfault.
> >    
>
> It will not, since it uses the same constructor, only with RefPtr wrapped
> over the constructed object.  I actually _checked_ this and experienced
> the same crash, as expected.
>
> Can anyone check if this happens with recent Gtkmm too?  Can anyone
> understand (and fix) the reason of the crash?
>
> (I might have not been nice, but it's not like I asked the list when I
> first saw the crash.  I encountered it in a real program, pondered for a
> while and created small test below.  I'm pretty sure it's a problem/bug of
> Gtkmm, but cannot check with recent versions.)
>
> Paul
>
>
> #include <glibmm/refptr.h>
> #include <gtkmm/main.h>
> #include <gtkmm/radioaction.h>
> #include <gtkmm/stock.h>
>
>
> namespace
> {
>
>  class Radio_action : public Gtk::RadioAction
>  {
>  public:
>
>    Radio_action (Group& group)
>      : Gtk::RadioAction (group, "test", Gtk::StockID (), "", "")
>    { }
>
>    static  Glib::RefPtr <Radio_action>
>    create (Group& group)
>    {
>      return Glib::RefPtr <Radio_action> (new Radio_action (group));
>    }
>  };
>
> }
>
>
> int
> main (int argc, char** argv)
> {
>  Gtk::Main  main (argc, argv);
>
>  Radio_action::Group  test_group;
>
> #if 1
>  // This segfaults.
>  Radio_action::create (test_group);
> #else
>  Gtk::RadioAction::create (test_group, "test");
> #endif
>
>  return 0;
> }
> _______________________________________________
> gtkmm-list mailing list
> gtkmm-list gnome org
> http://mail.gnome.org/mailman/listinfo/gtkmm-list
>
>