// valac --pkg gtk+-3.0 --pkg gdk-x11-3.0 test.vala

public class App : Gtk.Application
{
    construct
    {
        application_id = "org.app.testing";
    }

    public override void activate ()
    {
        print ("user time: %u\n",
            Gdk.X11Display.get_user_time (Gdk.Display.get_default ()));
        new Gtk.ApplicationWindow (this).show_all ();
    }
}

int main (string[] args)
{
    Gtk.init (ref args);
    return new App ().run (args);
}