Re: gtk and multithreading]

[Ralph Walden <rwalden tripos com>]

In my case, the worker thread could do what it needed to do
by setting a variable that some other callback to use.  The
thread didn't really NEED to call any gtk functions.  I can
see that you might need to however.  

One crappy way of doing it would be to set some flag variables,
and then check them in the main thread in a timer callback.

The alternative seems to be to wrap every call to GTK in a 
GDK_THREADS_ENTER/LEAVE() pair.  YEAAACHH...



Brad House wrote:
> 
> Hmm.  How did you "set flags" for the main thread to act
> upon it?  Did you have to emit some sort of signal?
> when running gtk_main() the only way to interact with it
> seems to be with signals or events...
> 
> what you're saying makes sense...I just don't know how to
> do it!
> 
> Thanks.
> -Brad
> 
> Ralph Walden wrote:
> >
> > I had a similar problem using threads in a GTK application.
> > My problem was that my final gtk_main_quit would not end the
> > application.  I suppose it has to do with GTK not enjoying
> > multiple threads calling into GTK functions.
> >
> > I solved my problem by making darn sure that my worker thread
> > made no GTK calls, just setting flags for the main thread to
> > act upon.  I know that there are gdk functions for thread enter/exit,
> > but I don't understand how to use them.
> >
> > Do you have to wrap EVERY call to any gtk/gdk API functions with the
> > thread enter/exit calls in a multi-threaded app?
> >
> > Is there a threading FAQ for GTK?
> >
> > Thanks all,
> >
> > Ralph Walden
> >
> > Brad House wrote:
> > >
> > > I've got a problem.
> > >
> > > The main program I have calls gtk_main()
> > > and everything works great until I get into threads.
> > >
> > > What I'm trying to do is call a thread to connect to a remote
> > > server. And when it recieves a response, it needs to pop up a
> > > window showing the response.
> > >
> > > Well anyhow it works for the most part...I'm using libglade
> > > so I'm doing a gtk_widget_show(widget);  where the widget has
> > > already been referenced and hidden, etc.  But the use of
> > > libglade should be most irrelevant.
> > >
> > > the only problem is that the widget won't display until I move
> > > the mouse...
> > >
> > > if I use gtk_widget_show_now(widget) instead it gives me an error
> > > about the main loop running in another thread, but again it displays
> > > properly as soon as I move the mouse.
> > >
> > > The only solution I can think of is to emit an event of some sort, and
> > > have the main loop capture the event and show the window for me instead
> > > of having my thread do it, but this is my first attempt at creating any
> > > GUI ... ever ... anywhere. So, the whole event structure is new to me
> > > (but I seem to have everything else besides threads down!)
> > >
> > > Also, I looked at the example in the FAQ, and it IS showing a redraw
> > > of a text field.  So it seems as though a thread can update the GUI,
> > > so this really confuses me...maybe I'm not using the gdk_enter_thread()
> > > stuff properly....
> > >
> > > Any help would be much appreciated...thank you.
> > >
> > > -----------------------------
> > > Brad House
> > > Sr. Developer
> > > Main Street Softworks, Inc.
> > >
> > > brad mainstreetsoftworks com
> > > (352) 378-8228
> > > -----------------------------
> > >
> > > _______________________________________________
> > > gtk-list mailing list
> > > gtk-list gnome org
> > > http://mail.gnome.org/mailman/listinfo/gtk-list
> >
> > --
> >
> > Ralph E. Walden
> > Tripos, Inc.
> > rwalden tripos com
> 
> --
> -----------------------------
> Brad House
> Sr. Developer
> Main Street Softworks, Inc.
> 
> brad mainstreetsoftworks com
> (352) 378-8228
> -----------------------------
> 
> _______________________________________________
> gtk-list mailing list
> gtk-list gnome org
> http://mail.gnome.org/mailman/listinfo/gtk-list

-- 

Ralph E. Walden
Tripos, Inc.
rwalden tripos com