How to get CN from an SSL connection

gistfile1.lisp

(usocket:with-client-socket (socket stream "encrypted.google.com" 443)
           (let* ((enc (cl+ssl:make-ssl-client-stream stream))
                  (crypto (cl+ssl::ssl-stream-handle enc))
                  (cert (cl+ssl::ssl-get-peer-certificate crypto))
                  (subj (cl+ssl::x509-get-subject-name cert)))
             (format t "entry count: ~s~%" (cl+ssl::x509-name-entry-count subj))
             (cffi:with-foreign-pointer (buf 10240)
               (let ((result (cl+ssl::x509-name-get-text-by-nid subj 13 buf 10240)))
                 (if (= result -1)
                     (format t "Could not find nid~%")
                     (format t "Subject name: ~s~%" (cffi:foreign-string-to-lisp buf)))))))