(use-modules (rnrs bytevectors) (rnrs io ports))
(let ((port (open-bytevector-input-port
	     (string->utf8 "Blablabla\nBlablabla\n"))))
  (seek port 13 SEEK_SET)
  (format #t "~c ~d\n" (peek-char port)
	  (ftell port)))
;; Outputs b 3 but should output b 13