Index: /trunk/source/level-1/l1-streams.lisp
===================================================================
--- /trunk/source/level-1/l1-streams.lisp	(revision 14521)
+++ /trunk/source/level-1/l1-streams.lisp	(revision 14522)
@@ -3351,4 +3351,5 @@
                    ((:character-special :tty) (#_fpathconf fd #$_PC_MAX_INPUT))
                    (t nominal))))
+    (when (<= octets 0) (setq octets nominal))
     (case (subtag-bytes (element-type-subtype element-type) 1)
       (1 octets)