mark (07/20/82)
Could someone who is familiar with the pty driver answer a question for me?
I tried installing some ptys on my 4.1BSD system, and then used them by putting
a getty on ttya and doing 'cu ttya'. It works fine for a minute or two,
allowing me to get logged onto the pty and type a few commands. Then, suddenly
cu thinks it lost the line. Turns out one of the reads on the controller end
returned a -1, with errno set to ENXIO. ("No such device or address.") I
couldn't see anything in the driver that could generate this. I changed cu
to ignore the error condition and it seemed to work OK.
What would cause a pty controller device to return a read error? What is
the standard technique for programming around this - just ignore the error?
This seems dangerous - perhaps only ENXIO's should be ignored. Anyone know
what possible errors there might be?
Reply to mark@Berkeley on the arpanet. Thanks much.