Index: io.c
===================================================================
--- io.c	(revision 25765)
+++ io.c	(working copy)
@@ -1215,8 +1215,9 @@
  *     r, w = IO.pipe
  *     r.eof?  # blocks forever
  *
- *  Note that <code>IO#eof?</code> reads data to a input buffer.
- *  So <code>IO#sysread</code> doesn't work with <code>IO#eof?</code>.
+ *  Note that <code>IO#eof?</code> reads data to the input buffer.
+ *  So <code>IO#sysread</code> only works with <code>IO#eof?</code>
+ *  if you call <code>IO#rewind</code> first.
  */
 
 VALUE