On Sat, 21 Mar 1998, Paul A Vixie wrote:

> I've always preferred to have O_NONBLOCK just be a way to force an
> EWOULDBLOCK errno rather than a way to bypass carrier checking, but
> I don't know how to get a tty device open (so I can set its CLOCAL)
> if its carrier isn't up unless we use O_NONBLOCK on tty devices to
> mean "ignore carrier when opening, but return EIO on read and write
> unless either carrier is on or CLOCAL is on".  Maybe a new open flag
> like O_IGNCARR?

As far as I am concerned, this is the true matter behind the cua/tty
debate.  I too get an icky feeling when using O_NONBLOCK to ignore carrier
detect on open.  If someone solve it some other way I will be just as
satisfied and will shut up about the whole thing.  However, it seems
really wrong to export an idea like ``carrier detect'' into the open()
call.  Thus, I find the cua/tty device split as the best option so far.

-J