* io.c (rb_io_rewind, rb_io_eof): add rdoc. based on a patch from

  Roger Pack in [ruby-core:26771] [Bug #2377].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27361 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 6 insertions, 2 deletions

diff --git a/io.c b/io.c
index 3afa413183..2c18e07c75 100644
--- a/io.c
+++ b/io.c
@@ -1159,6 +1159,8 @@ static void clear_readconv(rb_io_t *fptr);
  *     f.rewind     #=> 0
  *     f.lineno     #=> 0
  *     f.readline   #=> "This is line one\n"
+ * 
+ *  Note that it cannot be used with streams such as pipes, ttys, and sockets.
  */
 
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@@ -1241,8 +1243,10 @@ io_fillbuf(rb_io_t *fptr)
  *     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> may not behave as you intend with
+ *  <code>IO#eof?</code>, unless you call <code>IO#rewind</code>
+ *  first (which is not available for some streams).
  */
 
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