> (define vect (make-u8vector 3))
> (call-with-input-string "string" (lambda (pt) (read-subu8vector vect 0 2 pt)))
*** ERROR IN call-with-input-string -- Input port character buffer is not empty
(read-subu8vector '#u8(0 0 0) 0 1 '#<input-port #2 (string)>)
read-subu8vector calls macro-lock-and-check-input-port-character-buffer-empty
I guess it's a bug since I don't see what would be the use. Or enlighten me...