reverting non-file buffers in earlier Emacs versions.

[Luc Teirlinck <teirllm@dms.auburn.edu>]

I suggest the following documentation changes to autorevert.el and
emacs-xtra.texi.  The reason for the changes is that in Emacs versions
21.3 and earlier, autoreverting of non-file buffers seems to cause
serious problems.  In Emacs-21.3, Dired buffers autorevert every five
seconds, print a message every five seconds, constantly overshouting
what I am trying to type in the echo area, and point in a Dired buffer
shoots back to the beginning of the buffer every five seconds.

So I want to give the reader at least some indication that
autoreverting of non-file buffers worked quite differently in earlier
Emacs versions.

I will install if there are no objections.

===File ~/autorevert-diff===================================
*** autorevert.el	29 Dec 2004 21:08:55 -0600	1.42
--- autorevert.el	23 Jan 2005 21:57:14 -0600	
***************
*** 208,213 ****
--- 208,216 ----
  of files.  You may still sometimes want to revert them manually.
  
  Use this option with care since it could lead to excessive auto-reverts.
+ This is especially true in versions 21.3 and earlier of Emacs,
+ but should be much less of a problem in 21.4 or later.
+ 
  For more information, see Info node `(emacs-xtra)Autorevert'."
    :group 'auto-revert
    :type 'boolean
============================================================

===File ~/emacs-xtra-diff===================================
*** emacs-xtra.texi	18 Jul 2004 11:01:23 -0500	1.7
--- emacs-xtra.texi	23 Jan 2005 21:50:29 -0600	
***************
*** 10,16 ****
  @copying
  This manual describes specialized features of Emacs.
  
! Copyright (C) 2004
  Free Software Foundation, Inc.
  
  @quotation
--- 10,16 ----
  @copying
  This manual describes specialized features of Emacs.
  
! Copyright (C) 2004, 2005
  Free Software Foundation, Inc.
  
  @quotation
***************
*** 96,101 ****
--- 96,106 ----
  implemented, that is, for the types of buffers listed in the menu
  below.
  
+ This chapter describes the behavior in Emacs versions 21.4 or later.
+ In earlier versions, auto-reverting of non-file buffers, while
+ possible, could cause several problems such as excessive reverts,
+ excessive noisiness, inappropriate point movement and the like.
+ 
  Like file buffers, non-file buffers should normally not revert while
  you are working on them, or while they contain information that might
  get lost after reverting.  Therefore, they do not revert if they are
============================================================