isbackground      750 kern/tty.c     		while (isbackground(p, tp) &&
isbackground     1451 kern/tty.c     	if (isbackground(p, tp)) {
isbackground     1703 kern/tty.c     	if (isbackground(p, tp) &&
isbackground      301 kern/tty_pty.c 		while (isbackground(p, tp)) {