I want to first thank Guy Harris for all of his help he has
given me concerning these tty devices.
I need just a little bit more info ( I hope) to figure all
of this out.
The manual states that open will block when opening a device
that is a communication device with no carrier. I confirmed
that this works. It also states that when O_NDELAY is set,
the open will not block.
I also confirmed this. QUESTION: Does the open suppose to succeed?
My open did with no carrier and O_NDELAY.
Now for the confusion. With login ( ie getty engaged) turned on`
in /etc/ttytab, the open will block with O_NDELAY set. Reading
through the man pages for the zs devices, I got the idea it was
suppose to, but I want some confirmation because the man pages
are not clear about this point. If it is suppose to hang, has
getty done something to make this happen?