using Gtk; int main (string[] args) { Gtk.init (ref args); var window = new Window (); window.title = "First GTK+ Program"; window.border_width = 10; window.window_position = WindowPosition.CENTER; window.set_default_size (350, 70); window.destroy.connect (Gtk.main_quit); var button = new Button.with_label ("Click me!"); button.clicked.connect (() => { button.label = "Thank you"; }); window.add (button); window.show_all (); Gtk.main (); return 0; }