Welcome to the CHICKEN Scheme pasting service

(use srfi-18 mailbox)

(define mbox (make-mailbox))
(define primordial (current-thread))

(define t (thread-start! (lambda ()
                           (thread-sleep! 1)
                           (thread-signal! primordial 'example))))

;; this hangs forever and eats all my cycles (with timeout)
(print (mailbox-receive! mbox 4))

;; this exits as expected with the 'example exception (no timeout)
(print (mailbox-receive! mbox))