life after death (of uport)

[Vernon Schryver]

> vjs at calcite.UUCP (Vernon Schryver)  [the undersigned] wrote:
> >                      The 2.0.2 driver seems to understand NDELAY to mean
> >(1) "open even if DCD is false, and die if ever NDELAY and DCD are both
> >false", instead of (2) "open even if DCD is false, and do not pay attention
> >to DCD until DCD has been true."   Whatever, the result is that cu(1)
> >looses the port as soon as it turns off NDELAY. 
 
In article <1355 at ctisbv.cti-software.nl>, pim at cti-software.nl (Pim Zandbergen) writes:
> This is exactly how NDELAY should work. You should set CLOCAL immediately
> after having opened with O_NDELAY, if you want to keep the line after
> having turned off NDELAY.
> 
> Cu and uucp will do this if you specify \M (set CLOCAL) and \m (turn it off)
>in the Dialers file. This feature was introduced in HDB uucp in System V r 3.1.
> Pim Zandbergen                                 internet : pim at cti-software.nl
> CTI Software BV                                uucp     : ..!uunet!ctisbv!pim
> Laan Copes van Cattenburch 70                  phone    : +31 70 542302
> 2585 GD The Hague, The Netherlands             fax      : +31 70 512837

I disagree.  It is fine for open(2) wait until DCD is true unless NDELAY
is present.  It is good to suffer SIGHUP and permanent "eof" (read(2)==0)
after the driver sees a falling edge.  It is wrong to generate SIGHUP or
eof if DCD has not changed.  I did try \M & \m, and there is no way I can
find to set CLOCAL soon enough.

If ISC is right, then SVR3.2 cu(1) and UUCP do not work for any modem which
supports out-going carrier indication.  I repeat, if you do it "right" by
my definition, not only do cu & UUCP work, but so do uugetty, SLIP, etc.
It seems likely to me that my definition of right is not that far from
AT&T's.  At least, for one major workstation maker, my word is canonical.

I don't recall seeing the \[mM] stuff in the source until SVR3.2, at least
on the 3B2 tape, from which I merge AT&T changes with local "improvments."


Vernon Schryver
vjs at calcite.uucp