Re: Question about handling SIGINT properly in Guile

[Vijay Marupudi]

> So there is two things with signals.  First, when a process get a signal
> queued, the OS only deliver the signal -- at least on linux -- when
> going back to user-space.  Typically, before the process get
> re-scheduled or after a system call.  So sending a signal is not
> immediate.  Furthermore, Guile also queues the signals and deliver them
> to threads with async marks I think.

I understand. I don't get this problem with C, so I assume it's the
asynchronity of Guile that is my issue. I tried running the
scm_async_tick function, which the documentation says runs queued asyncs
(by providing a 'safe point', but that doesn't seem to change anything.

(define-module (testing)
  #:use-module (system foreign)
  #:use-module (system foreign-library))

(define tick
  (foreign-library-function #f "scm_async_tick"))

(define quit? #f)

(sigaction SIGINT (lambda (arg)
                    (pk "SIG" arg)
                    (set! quit? #t)))

(let loop ()
  (pk "QUIT-CHECK")
  (tick)
  (if quit?
      (begin (format #t "Quitting!~%") (exit 0))
      (begin (pk "WORK" (do ((i 0 (+ i 1))
                             (sum 0 (+ sum i)))
                            ((= i 1000) sum)))
             (let ((ret (sleep 10)))
               (pk "SLEEP" ret)
               (loop)))))


~ Vijay