signal handling different in 1.8.3 than 1.8.1?

[Gregory Marton <gremio@csail.mit.edu>]

Hi folks,

Now that I've upgraded to 1.8.3 from 1.8.1, some old test cases are 
failing.  In particular:

(define (ensure body-lambda ensuring-lambda)
    (dynamic-wind
        (lambda () #t)
        body-lambda
        ensuring-lambda))

(define (with-sigaction signum handler flags lamb)
      (let ((old-sigaction (sigaction signum)))
        (if flags (sigaction signum handler flags) (sigaction signum handler))
        (ensure
         lamb
         (lambda ()
           (sigaction signum (car old-sigaction) (cdr old-sigaction))))))

;; imagine an appropriate (assert bool message) and (assert-equal a b msg)

(let ((orig (sigaction SIGALRM))
        (sigcalled #f))
     (with-sigaction
      SIGALRM (lambda (sig) (set! sigcalled #t)) #f (lambda () (raise SIGALRM)))
     (assert sigcalled "we set and handled an alarm")) ;; FAILS in 1.8.3
     (assert-equal orig (sigaction SIGALRM) "returned to the original state")
     (let ((outer "nop")
           (inner "nop"))
       (with-sigaction
           SIGALRM (lambda (sig) (set! outer "outer")) #f
           (lambda ()
             (with-sigaction
              SIGALRM (lambda (sig) (set! inner "inner")) #f
              (lambda ()
                (raise SIGALRM)))
             (raise SIGALRM)))
       (and (assert-equal "inner" inner "inner sig got handled") ;; FAILS
            (assert-equal "outer" outer "outer sig got handled")))
     (assert-equal orig (sigaction SIGALRM) "returned to the original state")

All of these passed in 1.8.1.  If this is no longer The Recommended Way, 
how would one go about it?

Many thanks,
Grem

-- 
------ __@   Gregory A. Marton                http://csail.mit.edu/~gremio/
--- _`\<,_                                                                .
-- (*)/ (*)          Lots of Insidious Silly Parentheses (LISP :-)
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