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Didn't emacs add actual support for OS threads recentishly?

• Paul-Craft 4y ago
  Not to my knowledge. Apparently, according to https://www.emacswiki.org/emacs/NoThreading https://www.emacswiki.org/emacs/NoThreading, dynamic scope makes it devilishly difficult to implement os-level threading. It is, apparently, possible to automatically translate elisp into a lexically scoped lisp dialect, and rebuilt emacs on that foundation, but, again, to my knowledge, nobody's done that. And, there are occasional mutterings about making a new, natively multithreaded emacs, but nothing's ever made it into the GNU emacs repo, AFAIK. It does have process-based concurrency, which is basically where you spawn off a whole new emacs, then run your code within that. I've never used it, so I don't know how it works, other than the obvious disadvantage of having a large startup time and potentially memory use to start up another instance of emacs.
  • gpderetta 4y ago
    You are indeed right. I had understood that actual preemptive threads had been added, but it seems that for now it is still cooperative and requires explicit yields. Note that elisp has lexical scoping now, but it will be years of course before all packages will have been updated (and for many things you still want dynamic scoping).