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Date: Sat, 29 Jul 1995 06:40:16 -0700
From: Bruce Evans <bde>
Message-Id: <199507291340.GAA20080@freefall.cdrom.com>
To: CVS-commiters, cvs-sys
Subject: cvs commit: src/sys/sys tty.h
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bde         95/07/29 06:40:15

  Modified:    sys/kern  tty.c tty_conf.c
               sys/net   if_ppp.c if_sl.c
               sys/sys   tty.h
  Log:
  Obtained from:	partly from ancient patches by ache and me via 1.1.5
  
  Remove nullmodem().
  
  It may be useful to have a null modem routine, but nullmodem()
  wasn't one.  nullmodem() was identical to ttymodem() except it
  didn't implement MDMBUF (carrier) flow control, didn't do any
  wakeups for off to on carrier transitions, and didn't flush the
  i/o queues for on to off carrier transitions (flushing has the side
  effect of waking up readers and writers) although it did generate
  SIGHUPs.  The wakeups must normally be done even if nullmodem() is
  null in case something is sleeping waiting for a carrier transition.
  In any case, the wakeups should be harmless.  They may cause bogus
  results for select(), but select() is already bogus for nonstandard
  line disciplines.