;karlheg@inetarena.com (Karl M. Hegbloom) writes:

;>  Does anyone have any code that shows how to use threads in Guile
;> scheme?  I would like to test my build, and also to see how to make
;> threads.

;Here's a small example:

;----------------------------------------------------------------------
(define c 0)

(define q #f)

(define (start)
  (set! q #f)
  (begin-thread
   (let loop ()
     (if (not q)
	 (begin
	   (set! c (1+ c))
	   (select () () () 0 10000)
	   (loop))))))

(define (stop)
  (set! q #t))
;----------------------------------------------------------------------

;Type (start) to spawn the thread.

;Look at the counter by evaluating `c'.

;Type (stop) to kill the thread.

;Here's an example using the newly released guile-tcltk snapshot:

;----------------------------------------------------------------------
;(use-modules (tcltk tcltk))

;(tk-main-window "Hand" "200x200")
;(define c (canvas #f))
;(pack c)

;(define pi 3.1416)

;(define x0 100)
;(define y0 100)
;(define (x1 a) (+ x0 (* 100 ($cos a))))
;(define (y1 a) (- x0 (* 100 ($sin a))))

;(define angle (/ pi 2))
;(define delta 0.005)
;(define hand (c 'create 'line x0 y0 (x1 angle) (y1 angle)))

;(define moving? #t)

;(define (hand-loop)
;  (if moving?
;      (begin
;	(set! angle (+ angle delta))
;	(c 'coords hand x0 y0 (x1 angle) (y1 angle))
;	(select () () () 0 5000)
;	(hand-loop))))

;(define mu (make-mutex))
;(define cv (make-condition-variable))

;(begin-thread
; (let loop ()
;   (set! moving? #t)
;   (hand-loop)
;   (wait-condition-variable cv mu)
;   (loop)))

;(define (start)
;  (signal-condition-variable cv))

;(define (stop)
;  (set! moving? #f))
;----------------------------------------------------------------------

;/mdj