diff --git a/src/code/fd-stream.lisp b/src/code/fd-stream.lisp
index e41b33193ba97be0acc78d13b3ad953b9ff55baf..7fcd0bca8599967bbd1858f9408d07a6ad20b709 100644
--- a/src/code/fd-stream.lisp
+++ b/src/code/fd-stream.lisp
@@ -1756,8 +1756,9 @@
 		   #+nil
 		   (progn
 		     (format t "in-buffer-length = ~D~%" in-buffer-length)
+		     (format t "in-length = ~D~%" (fd-stream-in-length stream))
 		     (format t "fd-stream-in-index = ~D~%" (fd-stream-in-index stream)))
-		   (decf posn (- in-buffer-length
+		   (decf posn (- (fd-stream-in-length stream)
 				 (fd-stream-in-index stream))))
 		 #+nil
 		 (format t "fd-stream-unread = ~S~%" (fd-stream-unread stream))