Re: "Asynchronous Requests from Emacs Dynamic Modules"

[Eli Zaretskii <eliz@gnu.org>]

> From: Akira Kyle <ak@akirakyle.com>
> Cc: yyoncho@gmail.com, all_but_last@163.com, emacs-devel@gnu.org,
>  monnier@iro.umontreal.ca, p.stephani2@gmail.com
> Date: Sat, 31 Oct 2020 18:14:32 -0600
> 
> It seems the lisp threading functionality is still pretty beta 
> quality. Have the data races that Chris Wellons mentions here [1] 
> ever been addressed?

It's hard to tell, because that blog has no specifics, just a broad
accusation.  It is also quite old.

> It looks like it's mostly just exposing the pthread interface.

That's simply not true.  It _uses_ pthreads to start and manage
threads, and to implement mutexes, condvars, etc.  But if you look
closely at the level of thread.c (_not_ systhread.c), you will see
something very different from a typical pthreads application.

> What is the use case for the current lisp threads given the severe
> limitation that only will ever run at a time and the constraints the
> cooperative nature puts on when threads can switch?

The main use case is to allow you to write one or more background Lisp
programs that go about their job while a foreground command lets the
user interact normally with Emacs.