if (tty_register_ldisc(N_SYNC_PPP, NULL) != 0) 
if (tty_unregister_ldisc(N_SYNC_PPP) != 0) 
ppp_sync_cleanup(void){	if (tty_register_ldisc(N_SYNC_PPP, NULL) != 0)		printk(KERN_ERR "failed to unregister Sync PPP line discipline\n");}
4520	/local/tlutelli/issta_data/temp/c/2005_temp/2005/4520/64ccd715d3cf498318b14b646ce5f97e7ab15bb5/ppp_synctty.c/clean/drivers/net/ppp_synctty.c