Re: Shrinking the C core

[Eli Zaretskii]

> From: Emanuel Berg <incal@dataswamp.org>
> Date: Fri, 15 Sep 2023 19:11:22 +0200
> 
> Eli Zaretskii wrote:
> 
> >> I think the biggest problem with uncooperative
> >> multi-threading in Emacs is that Emacs has so much global
> >> state. As a consequence, it's unsafe to let two threads use
> >> anything in the C code in parallel.
> >
> > Indeed, that's the main problem. Just adding threads to Lisp
> > is easy.
> 
> Is there a part that is safe to access in parallel?

No.  The global state cannot be possibly accessed in parallel from two
or more threads.

> If not, or for the part that is unsafe, where is
> synchronization of access to be done, in Lisp or in C?

Both.