Drawing on the root window

[Joao Victor <jvital gmail com>]

Hello folks,

I'm trying to draw on the root window using the gtk API, but with no
success. Basically this is what i'm trying to do:

---------- begin code -------------

static void draw( GtkWidget *widget,
                         gpointer   data ) {

   GdkWindow *root_window;
   GdkPixmap *pixmap;
	
   root_window = widget->window;
   pixmap = gdk_pixmap_new(root_window,
			  100,
			  100,
			  -1);
	
   gdk_draw_rectangle (pixmap, widget->style->black_gc, TRUE, 0, 0, 100, 100);

---------- end code -------------

But it doesn't happen anything. Could somebody please help me?

Thanks,
J.V.