GtkStatusIcon::set_from_stock

void set_from_stock(GtkStockItems stock_id);

Set icon image of the GtkStatusIcon using the supplied stock_id. The icon image should easily identify the state of the item being monitored by the user.

$tray = new GtkStatusIcon();
$tray->set_from_stock(Gtk::STOCK_EXECUTE);

See also: GtkStatusIcon::new_from_stock()