diff --git a/man2/poll.2 b/man2/poll.2
index ffd718c8d..390e7a9b7 100644
--- a/man2/poll.2
+++ b/man2/poll.2
@@ -83,7 +83,8 @@ file descriptor for a single
 .BR poll ()
 call: simply negate the
 .I fd
-field.)
+field.
+Note, however, that this technique can't be used to ignore file descriptor 0.)
 
 The field
 .I events