Re: Reading from pipes directly with a process-filter

[Eli Zaretskii]

> From: "Peter" <emacs@nexoid.at>
> Date: Fri, 13 Jan 2023 20:01:37 +0100
> 
> I've been slowly sliding into using Emacs more and more like a Lisp OS,
> so one thing that has come up is directly reading data from pipes or
> special devices (like /dev/input/event...). I can do that fine by
> running `start-process' with `cat /dev/input/event..', however that
> seems a bit wasteful. Is there any way to *directly* open such a file
> and put a process-filter in front of it?

Did you try to use make-pipe-process?

> Semi-relatedly, is there any support for `fnctl' or `ioctl' in elisp, so
> that I could even *write* to those special devices?

Doesn't a simple 'write' (a.k.a. write-region in Emacs) work?  If not,
can you show a recipe that fails with all the details?