> On Nov 7, 2022, at 1:19 PM, Marc Feeley <xxxxxx@iro.umontreal.ca> wrote:
>
> Note that ##thread-call can be written on top of ##thread-int! (using a mutex to wait for the result).  So ##thread-int! is the fundamental primitive.

For completeness here is the implementation:

(define (make-locked-mutex)
  (let ((mut (make-mutex)))
    (mutex-lock! mut)
    mut))

(define (thread-call thread thunk)
  (let ((mut (make-locked-mutex))
        (result #f))
    (##thread-int!
     thread
     (lambda ()
       (set! result (thunk))
       (mutex-unlock! mut))) ;; result is ready!
    (mutex-lock! mut) ;; wait for result
    result))

Marc