在sbcl lisp中使用線程時在lisp中變量unbound

Question

我正在使用add和shift方法在​​sbcl中編寫一個程序來乘以兩個數字。而我的正常程序會很好地運行，但是當我使用線程時，程序顯示沒有輸出並且沒有錯誤消息。我應該刪除代碼中是否有任何錯誤。

(use-package :sb-thread) 
(defvar *buffer-queue* (make-waitqueue)) 
(defvar *buffer-lock* (make-mutex :name "buffer-lock")) 
(defvar *buffer* (list nil)) 

(defun writer() 
    (let ((res 0)) 
     (loop for lpr from 0 to 63 
       do (let ((end-bit (logand num2 1))) 
       (with-mutex (*buffer-lock*) 
        (setf *buffer* (cons end-bit *buffer*)) 
        (setq num2 (ash num2 -1)) 
        (condition-notify *buffer-queue*) 
       ))))) 

(defun reader() 
    (let ((end-bit 0) (res 0)) 
    (with-mutex (*buffer-lock*) 
     (loop 
     (condition-wait *buffer-queue* *buffer-lock*) 
      (loop 
       (unless *buffer* (return)) 
       (end-bit (car *buffer*)) 
       (setf *buffer* (cdr *buffer*))))) 
    (if (= end-bit 1) 
        (setq res (+ res num1))) 
     (setq num1 (ash num1 1)) 
     (format t "result is ~a.~%" res) 
    ) 
) 





(let ((num1 (progn 
       (write-line "Enter first number: ") 
       (finish-output) 
       (read))) 
     (num2 (progn 
       (write-line "Enter second number: ") 
       (finish-output) 
       (read)))) 
    (if (or (= num1 0) (= num2 0)) 
     (write-line "result is 0.0") 
     (calculator num1 num2)) 

）

爲什麼它是怎麼回事？

Answer 1

爲了弄清楚發生了什麼，我強烈建議使用(trace writer)和(trace reader)（甚至可能是(trace calculator)）。

我也會建議使用bordeaux-thread，它只是一個墊片（bordeaux = shim用法語）來使線程在多個實現中工作。