ac_tty            220 kern/kern_acct.c 		acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev;
ac_tty            222 kern/kern_acct.c 		acct.ac_tty = NODEV;
ac_tty             57 sys/acct.h     	dev_t	  ac_tty;	/* controlling tty */