#include <gtk/gtk.h>
#include <ctype.h>
#include <string.h>

static gboolean
key_event (GtkWidget *entry, GdkEvent * event)
{
  if ((strlen (gtk_entry_get_text (GTK_ENTRY (entry))) < 3)
      && isdigit(event->key.keyval))
    {
      // don't abort
      return FALSE;
    }
  // abort event
  gtk_signal_emit_stop_by_name (GTK_OBJECT (entry), "key_press_event");
  return TRUE;
}

int
main (int argc, char *argv[])
{
  GtkWidget *win;
  GtkWidget *entry;

  gtk_init (&argc, &argv);

  win = gtk_window_new (GTK_WINDOW_TOPLEVEL);

  entry = gtk_entry_new ();
  gtk_container_add (GTK_CONTAINER (win), entry);

  gtk_signal_connect (GTK_OBJECT (entry), "key_press_event",
		      GTK_SIGNAL_FUNC (key_event), entry);

  gtk_widget_show_all (win);

  gtk_main ();

  return 0;
}