How do you force an expose event on a gtkglarea ?

[Jim Parker <hopeye cfl rr com>]

G'Day !

I'm writing a program that a user can draw interactively on a gtkglarea
with a mouse.
Basically the scribble example , but using a gtkglarea instead of the
gtk_drawing_area.

Currently in order to show the drawing, you need to resize the screen, how
can I force an expose event ?  Will gtk_widget_draw ( ) work ?

The examples I have seen either use Glut or swap a backing pixmap.  Neither
of which seem to apply in this case.

TIA

cheers,
Jim Parker