;; https://issues.guix.gnu.org/41948

(use-modules (ice-9 match))

(setvbuf (current-output-port) 'line)
(sigaction SIGCHLD pk)                            ;start signal thread

(match (primitive-fork)
  (0
   (format #t "child: ~a~%" (getpid))
   (let loop ()
     (unless (zero? (usleep 500000))
       ;; If this happens, it means the select(2) call in 'scm_std_select'
       ;; returned because one of our file descriptors had input data
       ;; available (which shouldn't happen).
       (format #t "child woken up!~%"))
     (loop)))
  (pid
   (format #t "parent: ~a~%" (getpid))
   (sigaction SIGALRM (lambda _
                        (format #t "alarm in parent!~%")))
   (let loop ()
     (kill (getpid) SIGALRM)
     (usleep 100000)
     (loop))))