QNOENB
{ SF(QNOENB), "Don't enable Q via putq" },
q->q_flag |= QNOENB;
q->q_flag &= ~QNOENB;
q->q_flag = QISDRV | QMTSAFE | QNOENB | QREADR | QUSE;
#define canenable(q) !((q)->q_flag & QNOENB)