using-continuations.scm

(define (do-read sock n)
  (linux/do-syscall 'read (sock n 'linux/onoblock)))

(define (read sock n)
  (let ((result (do-read sock n)))
    (if (equal? result 'linux/ewouldblock)
      (call-with-current-continuation
        (lambda (cc)
          (wait sock cc))
      result)))


;; Efficiently doing this requires keeping a queue of ready
;; tasks and a queue of not-ready tasks. You loop over the
;; ready tasks and run them until they wait, then push them
;; to the unready tasks. Then you loop over the unready tasks
;; and check if they're ready, if they are you push them to
;; a new ready queue and otherwise you push them to a new
;; unready queue.
(define (wait obj cont)
  nil)