JREC_ENDMAGIC
if (tailp->endmagic != JREC_ENDMAGIC) {
if (tail.endmagic != JREC_ENDMAGIC) {
ack.rend.endmagic != JREC_ENDMAGIC
rendp->endmagic = JREC_ENDMAGIC;
rendp->endmagic = JREC_ENDMAGIC;