(use posix extras)

(set-signal-handler! signal/chld void)

(let lp ((n 0))
  (receive (in out)
    (create-pipe)
    (let ((pid1 (process-fork (lambda ()
                                (file-close in)
                                (fprintf (open-output-file* out)
                                         "hi, there\n")
                                (exit 0))))
          ;; Trigger an early sigchld while reading from pid1's output
          (pid2 (process-fork void)))
      (file-close out)
      (let ((res (read-string #f (open-input-file* in))))
        (process-wait pid1)
        (process-wait pid2)
        (unless (string=? "hi, there\n" res)
          (printf "ERROR after ~A runs, got ~S\n" n res)
          (exit 1))))
    (lp (fx+ n 1))))