guy@uunet.uu.net (Guy Harris) (04/22/89)
>I'm a new SUN user and just brought up a 3/60 with Version 4.0. To my >surprise, the stty option [-]nohang was conspicuous by its absence. An oversight, as I remember. >This is the function that kills the control process if the remote carrier is >dropped, thus logging out the faulted user and clearing the remote >port. Actually, "nohang" is the function that tells the system *not* to kill the control process if the remote carrier is dropped. From the 4.3-tahoe TTY(4): When the carrier signal from the dataset drops (usually because the user has hung up his terminal) a SIGHUP hangup signal is sent to the processes in the distinguished process group of the terminal; this usually causes them to terminate. The SIGHUP can be suppressed by setting the LNOHANG bit in the local state word of the driver. "stty -nohang" tells the system to send a SIGHUP to all processes in the process group of the terminal (basically, all processes in the foreground job, at least under a job-control shell; all processes in the session, under a non-job-control shell) when carrier goes away. That setting ("stty -nohang") is the default. >An inquiry to some folks locally informed me that this option was present >in Version 3. Can anyone point me to a way of ressurecting [-]nohang or >achieving the same result another way? "stty clocal" is basically equivalent to "stty nohang" (and "stty -clocal" is equivalent to "stty -nohang"). "stty clocal" also has the effect that an open on the port won't wait for carrier to come up (yes, this does work - open the port no-delay, set "clocal", then do another open; this trick is used on occasion in S5-land). >Try looking at the "hupcl" option of stty. I believe you want >"stty hupcl", but I've never verified that it actually works as >advertised. --wnl Not quite. "hupcl" is the one that works the other way around - it controls whether carrier is dropped by the *local* machine when the last process holding the tty closes it, not whether processes attached to the tty are given a SIGHUP when carrier goes away. [[ Whups! Well.....close anyway. --wnl ]]