casier: a variable protected by a lock.

;; https://www.axess-industries.com/casiers-consignes/armoire-casier-a-effet-personnel-p-150576-600x600.jpg
;; casier: a box protected by a lock!

(terpri) (ql:quickload :bordeaux-threads)


(defstruct casier
  value
  (lock (bt:make-lock)))

(defun (setf casier) (new-value casier)
  (bt:with-lock-held ((casier-lock casier))
    (setf (casier-value casier) new-value)))

(defun casier (casier)
  (bt:with-lock-held ((casier-lock casier))
    (casier-value casier)))

(defparameter *stop-worker-thread* (make-casier))

(bt:make-thread (lambda ()
                  (loop
                    :do (sleep 0.1)
                        (princ "+")
                        (finish-output)
                    :until (casier *stop-worker-thread*)))
                :initial-bindings `((*standard-output* . ,*terminal-io*))
                :name "Test Casier")

(sleep 10)
(setf (casier *stop-worker-thread*) t)