Opinions solicted for changes to tty names in 1.7.10

Andy Koppe andy.koppe@gmail.com
Wed Jun 15 20:46:00 GMT 2011

On 15 June 2011 15:55, Christopher Faylor wrote:
> On Wed, Jun 15, 2011 at 01:28:55PM +0100, Andy Koppe wrote:
>>On 14 June 2011 21:36, Christopher Faylor wrote:
>>> After some discussion with Corinna, I'm thinking about making a change to
>>> the tty naming in Cygwin as part of the removal of CYGWIN=tty.
>>> (In case you haven't noticed, CYGWIN=tty, is no longer supported in
>>> snapshots. ??If you do have the tty option set you get one warning per
>>> session telling you to unset it.)
>>> Since the only thing using Cygwin's "tty layer" will now be ptys, I'd
>>> like to rename /dev/ttyN to /dev/ptyN. ??I've already added /dev/consN
>>> support for consoles but I'd like to change that so that consoles are
>>> represented as /dev/ttyN instead.
>>Makes plenty of sense.
>>The only concern I see is that BSD PTYs (as previously used on Linux
>>as well, IIRC) are called "pty[p-za-e][0-9a-f]" on the master side,
>>whereas they're "tty[p-za-e][0-9a-f]" on the slave side. Therefore
>>calling the slave side "ptyN" could conceivably cause issues.
>>Is the Unix98 scheme ("/dev/pts/N") that's used on Linux these days
>>out of the question?
> No.  I considered that but adding an arbitrary directory structure under
> out /dev kludge seemed wrong.  I would prefer to make it look more like
> Linux though.  The man reason why I didn't implement that is that I
> thought someone would report that "ls /dev/pts" doesn't work

Good point. Unlike "ls /dev/pty*", it would actually be useful as it's
supposed to contain the currently used ptys.

> not that it couldn't be made to work.

That would be nice.

>>> Corinna suggested that I should send a query here to see if anyone knows
>>> if this proposed change will affect any existing applications which use
>>> ptys like mintty, emacs, xterm, rxvt, or screen.
>>Mintty currently only looks for "tty" when cutting down the device
>>name to fill in the utmp.ut_id field, but that's trivial to change
>>(and utmp isn't on by default anyway).
> Shouldn't it just be using basename(3)?

The terminal is supposed to cut off all of "/dev/tty", especially as
Cygwin's ut_id is only 2 chars, whereas Linux's is 4.


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