RDF_CLOSING
while ((sc->sc_flags & (RDF_OPENING | RDF_CLOSING)) != 0)
sc->sc_flags |= RDF_CLOSING;
sc->sc_flags &= ~(RDF_CLOSING | RDF_WLABEL);
while (sc->sc_flags & (RDF_OPENING | RDF_CLOSING))
sc->sc_flags |= RDF_CLOSING;
sc->sc_flags &= ~(RDF_CLOSING | RDF_WLABEL);