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Re: term & user space console
From: |
Thomas Bushnell, BSG |
Subject: |
Re: term & user space console |
Date: |
30 Jan 2002 16:15:03 -0800 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.1 |
Marcus Brinkmann <Marcus.Brinkmann@ruhr-uni-bochum.de> writes:
> The obvious difference is what happens to data that is available in the
> underlying file while CREAD is turned off. Both, devio and ptyio discard
> such data, while in your design it would be delayed until CREAD is enabled.
> I couldn't find out what is the right thing (the standards just say "enable
> receiver" about CREAD).
It shouldn't be delayed, that would be a bug in my pseudocode.
On a real serial line, it gets dropped.
However, dropping it might involve a CPU spin, so some more thought
needs to happen I think.
> while (1)
> while (output suspended or queue empty)
> block until output resumed and queue non-empty
> write data -- blocking
>
> so basically the same, just taking output stopped into consideration.
By "data remains to be written" I was including stopped and all such
tests. :)
> Mmmh. There probably is a way, but I am not aware of it. Note that I was
> thinking about using io_select, not the glibc select function.
Um, the way is to interrupt it just like you interrupt a read...
> Mmmh. Interesting, and I see how term does this to the user. But how
> would the underlying node inform the bottom handler about it (in the
> transparent model).
You'd need to create the process hair, and use term_open_ctty. It
will then send signals at your process.
- Re: term & user space console, Marcus Brinkmann, 2002/01/27
- Re: term & user space console, Thomas Bushnell, BSG, 2002/01/27
- Re: term & user space console, Marcus Brinkmann, 2002/01/27
- Re: term & user space console, Thomas Bushnell, BSG, 2002/01/27
- Re: term & user space console, Marcus Brinkmann, 2002/01/30
- Re: term & user space console, Thomas Bushnell, BSG, 2002/01/30
- Re: term & user space console, Marcus Brinkmann, 2002/01/30
- Re: term & user space console, Roland McGrath, 2002/01/30
- Re: term & user space console, Thomas Bushnell, BSG, 2002/01/30
- Re: term & user space console,
Thomas Bushnell, BSG <=
- Re: term & user space console, Marcus Brinkmann, 2002/01/30
- Re: term & user space console, Marcus Brinkmann, 2002/01/30
- Re: term & user space console, Marcus Brinkmann, 2002/01/30
- Re: term & user space console, Niels Möller, 2002/01/31
- Re: term & user space console, Thomas Bushnell, BSG, 2002/01/31
- Re: term & user space console, Marcus Brinkmann, 2002/01/31
- Re: term & user space console, Thomas Bushnell, BSG, 2002/01/31
- Re: term & user space console, Marcus Brinkmann, 2002/01/31
- Re: term & user space console, Roland McGrath, 2002/01/31
- Re: term & user space console, Marcus Brinkmann, 2002/01/31