prog/vala/test.vala

int main (string[] args) {
   Gtk.init (ref args);

   var window = new Gtk.Window ();

   window.title = "This new window.";

   window.border_width = 10;

   window.window_position = Gtk.WindowPosition.CENTER;
   window.set_default_size (350, 80);

   window.destroy.connect (Gtk.main_quit);

   window.show_all ();

   Gtk.main ();
   return 0;
}