window.signal_close.connect(sigc::bind(sigc::mem_fun(this, &Ev::exit), 0));
keyboard.signal_button_press.connect(sigc::bind_return(sigc::mem_fun(this, &Ev::key_press), false));
keyboard.signal_button_release.connect(sigc::bind_return(sigc::mem_fun(this, &Ev::key_release), false));
window.signal_close.connect(sigc::bind(sigc::mem_fun(this, &Ev::exit), 0));
keyboard.signal_button_press.connect(sigc::bind_return(sigc::mem_fun(this, &Ev::key_press), false));
keyboard.signal_button_release.connect(sigc::bind_return(sigc::mem_fun(this, &Ev::key_release), false));