Re: multi-threaded Emacs

[Richard M Stallman]

    The cooperative threads approach moves to Elisp packages more work as
    they will have explicitly to yield control but it simplifies a lot the C
    code.

If thread-switching occurs inside QUIT, then Lisp code will never
need to explicitly say where switching occurs.

On the other hand, if thread-switching only occurs in
wait_reading_process_output, Lisp programs could permit
thread-switching by doing (accept-process-output).

The former would be more convenient.  Stefan said it has
problems, but didn't explain them yet.