Spin decrements by itself

[alblas <r alblas demon nl>]

In the callback of a spin button  some calculations are done in a loop
which can take some time (1 sec or less).
To prevent that the gui is dead during this time I have added a
g_main_iteration() in the loop.

Now, as soon as I click on the spin button (either up or down arrow) the

spin button starts to decrement 'by itself', until it has reached its
lowest
state.
If I remove the g_main_iteration() everything works normal.
Also, if I remove the long calculation, the spin button works as
expected.
So, the combination of g_main_iteration()  and a "long" execution time
of
the callback gives problems.

If replace the spin button by a normal button (and a printf in the
callback to see if it is activated) everything works fine (just 1
callback activation for each button press).

Any idea how to fix this? Or is it a gtk-bug?

See attached example.


Rob.

(Note: This problem was addressed earlier, I didn't get any reaction.
Maybe because it was in a wrong 'thread'?)

#include "gtk/gtk.h"
/* NOTE: Next is just a simple example which shows the spin problem.
         In reality the sleep is a loop in which a calculation 
         on several data items is done;
         the g_main_iteration() is also in this loop.
         The sleep is here 1 sec, but the problems also pop up with much less
         delay (100ms or even lesser).
*/

void func(GtkWidget *widget, gpointer data)
{
  char *name=(char *)data;
  if (!strcmp(name,"Spintest")) puts("Spin");

/* If one of the 2 next lines is removed the spin works fine. */
  sleep(1);                        /* simulate long execution time */
  while (g_main_iteration(FALSE)); /* serve gui */
}

int main(int argc, char **argv)
{
  GtkWidget *wnd,*spin;
  GtkObject *adjustment;

  gtk_init(&argc, &argv);
  wnd = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  adjustment = gtk_adjustment_new(10,0,100,1,1, 0.0);
  spin = gtk_spin_button_new(GTK_ADJUSTMENT(adjustment),1.0,1);
  gtk_signal_connect(GTK_OBJECT(adjustment),"value-changed",
                                  GTK_SIGNAL_FUNC(func), "Spintest");

  gtk_container_add(GTK_CONTAINER(wnd),spin);
  gtk_widget_show_all(wnd);

  gtk_main();
  return 0;
}