Re: Gnome/Gtk and thread safety

[Maciej Stachowiak <mjs eazel com>]

Havoc Pennington <hp redhat com> writes:

> Maciej Stachowiak <mjs eazel com> writes: 
> > We could take the classical Unix approach to fixing non-threadsafe
> > interfaces:
> > 
> >   widget = gtk_window_new_r ();
> > 
> > :-)
> > 
> > 
> > Actually, I don't get why the code you posted above with
> > gtk_window_new has a race; how could another thread even have access
> > to the value of `widget' right after you assign it, let alone want to
> > sink or unref it?
> > 
> 
> Assume it's a global variable, or a variable inside some other object
> inside some other object which is a global variable.
>
> A common case might be this code:
> 
>  static GtkWidget *dialog = NULL;
>  if (dialog == NULL)
>    dialog = gtk_dialog_new ();
> 
> You have to avoid the race; otherwise you'll get bizarre bugs
> eventually, pretty guaranteed.
> 

Oh my goodness, using global variables or function-scope statics
concurrently from multiple threads without locking is not threadsafe?
Have you published a paper on this new discovery yet? :-)

 - Maciej