Greeter
        .authenticate.username default=null
        .connect_sync replacement="LightDM.Greeter.connect_to_daemon_sync"
        .start_session.session default=null
        .start_session.cancellable default=null
        .start_session_sync.session default=null
        .authentication_user nullable=true
        .autologin_user_hint nullable=true
        .select_user_hint nullable=true
User
        .get_uid type="Posix.uid_t"
        .uid type="Posix.uid_t"