Re: Threads

[Russell Shaw <rjshaw netspace net au>]

Olexiy Avramchenko wrote:
> Russell Shaw wrote:
>
> > Hi,
> > In the faq on threads (http://www.gtk.org/faq/#AEN482), there is:
> >
> > int
> > main (int argc, char *argv[])
> > {
> >   GtkWidget *window;
> >
> >   /* init threads */     g_thread_init(NULL);
> >   gdk_threads_init();
> >
> >   /* init gtk */
> >   gtk_init(&argc, &argv);
> >
> >   window = create_window();
> >   gtk_widget_show(window);
> >
> >   gdk_threads_enter();
> >   gtk_main();
> >   gdk_threads_leave();
> >
> >   return 0;
> > }
> >
> > Because gdk_threads_enter()/leave() surround gtk_main(), then
> > wouldn't that mean other threads that use gdk_threads_enter()/leave()
> > are always blocked until gtk_main() exits?
>
>
> Hello,
> No, gtk_main unlocks mutex before g_main_loop_run() call and then GDK 
> code locks it just before gtk_main_do_event() call. So, mutex is locked 
> only when event is processing.

silly me, i did a case-sensitive grep for threads.

Ok, in gtkmain.c:

void
gtk_main (void)
{
  ...
  if (g_main_loop_is_running (main_loops->data))
    {
      GDK_THREADS_LEAVE ();
      g_main_loop_run (loop);
      GDK_THREADS_ENTER ();
      gdk_flush ();
    }
  ...
}

So if g_main_loop_run() runs for the duration of the app, then there is nothing
guarding gdk calls made by gtk callbacks. So, doesn't this mean that every gtk
operation in a gtk callback that eventually calls a gdk function, should be
surrounded by gdk_threads_enter()/leave() ?