Re: "Asynchronous Requests from Emacs Dynamic Modules"

[Akira Kyle <ak@akirakyle.com>]

On Sat, Oct 31, 2020 at 06:49 AM, Stefan Monnier 
<monnier@iro.umontreal.ca> wrote:

>> With Emacs 28, you can get a file descriptor to a pipe process 
>> and
>> send arbitrary data there (from arbitrary threads).
>
> Cool, so that takes care of it.
>
>> You'd still need some small protocol (e.g. JSON) to 
>> encode/decode
>> requests, but with that you can send arbitrary requests
>> back asynchronously.
>
> I don't think you need a complex protocol: just stash somewhere 
> (inside
> the module data structures) the data you need for the async 
> request,
> then send a dummy byte to the pipe.  On the Lisp side, just 
> install
> a process-filter which calls back the module to "run any pending 
> async
> requests".

Thanks Philipp for pointing this out! I'm glad this was already 
thought of and added so the SIGUSR1 hack isn't necessary going 
forward. For future reference, the module function is 
`open_channel`.