How to read a string output with `open-input-pipe` on Mac OS?

[Panisuan Chasinga]

Hi list, I want to read a string output using `ice-9/popen/open-input-pipe`
but somehow always got an empty string. Here is my test code:


(use-modules (ice-9 popen))
(use-modules (ice-9 textual-ports))

(define (test-read-port)
  (let* ((port (open-input-pipe "ls"))
           (str (get-string-all p)))
     (close-port p)
     str))


I was able to read from a file with `open-input-file`, but not
`open-input-pipe` with any command. Running `(system "ls")` seemed to work
just fine.