/dev/tty weirdness

[George Pontis]

How come any attempt to open /dev/tty ( as O_RDWR ) fails with the error
"No such device or address".  The system does have a character device
named tty with major 2, minor 0, and rw permission for all.

SunOS 4.0 / 3-60s and 3-50s.

[[ Perhaps the process doing the open has no control terminal?  Is it a
"daemon" or are you running it straight from a shell?  Does
"cat file >/dev/tty" work?  --wnl ]]