gtk and threads

[Ole Myren Rohne <ole dot rohne at cern dot ch>]

Sorry if this is off-topic, please tell if there is a dedicated
list for guile/gtk integration...

As I didn't expect gtk and threads to mix at all, I was surprised to
see that the naive approach sort of works - see below. 

However, when looking closer it appears that widget drawing is not
done properly: pressed buttons are not rendered as pressed and more
complicated examples (eg gtk-tree-new) gets totally messed up. I use a
slightly dated gtk-1.3.

I suspect (gtk-idle-add yield) is really causing the trouble. In fact, 
it seems that adding anything to the idle loop is bad even when no
threading is involved.

Then my question: Is there a way of making threads and gtk work together?

	Thanks, Ole


(use-modules (gtk gtk) 
             (ice-9 threads))
;;; Create hello/goodbye window
(let ((w (gtk-widget-new 'GtkWindow #:type 'toplevel #:title "hello"))
      (b (gtk-hbox-new #f 0))
      (b1 (gtk-button-new-with-label "hello"))
      (b2 (gtk-button-new-with-label "goodbye")))
  (gtk-signal-connect b1 "clicked" 
                      (lambda () 
                        (display "hello" (current-error-port))))
  (gtk-signal-connect b2 "clicked" 
                      (lambda () 
                        (display "goodbye" (current-error-port))
                        (gtk-widget-destroy w)))
  (gtk-container-add w b)
  (gtk-box-pack-start b b1 #f #f 1)
  (gtk-box-pack-start b b2 #f #f 1)
  (gtk-widget-show-all w))
;;; Start gtk-main in separate thread
(gtk-idle-add yield)
(call-with-new-thread 
 gtk-main 
 (lambda args 
   (display "throw from gtk-main: " (current-error-port)) 
   (display args (current-error-port))))
;;; Mess with gtk-idle-add
; (gtk-idle-add (lambda () (display #\. (current-error-port))))
;;; Start gtk-main normally
; (gtk-main)