ttydev_cdevsw has no d_purge

[Poul-Henning Kamp]

In message <CAJOYFBBbskRbXjKZdv-JgHi4vJgW0S0N2DGvZgm5_oDWcY65ig at mail.gmail.com>
, Ed Schouten writes:
>2012/8/2 Julian Elischer <julian at freebsd.org>:

TTYs are used *two* ways:  As terminals and as comms to the real world.

If a terminal-tty disappears, it should be handled like a HUP would
be, analytically it is the exact same situation as a carrier drop
on a modem.  The implementation may need to do tricky stuff, but the
result should be exactly like a HUP seen from userland.

If a comms-tty disappears, it should be handled like any other
disappearing device: ENXIO.


-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.