Re: Enhancing pty driver to act like a serial port?

[Grant Edwards <grante@visi.com>]

On 2008-06-22, Peter Åstrand <astrand@cendio.se> wrote:
>
>>The question of emulating a serial port in user-space has come
>>up a number of times in various contexts during the past few
>>years.  
>>
>>The current pty driver isn't really sufficient when the
>>application actually expects to be connected to a physical
>>serial port: 
>
> A better userspace solution would be great. I'm maintaining 
> cyclades-serial-client. It relies on LD_PRELOAD, which is not
> very elegant. 

I can imagine.   (I used a few Cyclades 8-port boards many
years ago, and always liked Cyclades' product lines).

>>you can't set parity or word length, and the modem
>>control/status ioctl() calls fail.
>
> Oh. I was just investigating why it's not possible to set
> "cs7" on the pty. stty fails with:
>
> $ stty cs7 -F /my/pty
> stty: /my/pty: unable to perform all requested operations
>
> I guess this explains it. 

Yup.  It wouldn't be difficult at all to make the pty driver
act like a serial device, but there's a huge difference between
something being easy to change and getting those changes
accepted.  Judging by the silence I got in response to my query
the chances of such a change being accepted are pretty much
zero.

-- 
Grant Edwards                   grante             Yow!  The PINK SOCKS were
                                  at               ORIGINALLY from 1952!! But
                               visi.com            they went to MARS around
                                                   1953!!

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