Update Backups chapter of Lisp manual.

* doc/lispref/backups.texi (Making Backups): Mention default value of backup-directory-alist.
(Rename or Copy): Note that backup-by-copying-when-mismatch is t.
(Auto-Saving): New minor mode behavior for auto-save-mode.
(Reverting): Add defvar for revert-buffer-in-progress-p.

1 files changed, 17 insertions, 10 deletions

diff --git a/doc/lispref/backups.texi b/doc/lispref/backups.texi
index de41efacdeb..2bcb768aea8 100644
--- a/doc/lispref/backups.texi
+++ b/doc/lispref/backups.texi
@@ -140,8 +140,8 @@ For the common case of all backups going into one directory, the alist
 should contain a single element pairing @samp{"."} with the appropriate
 directory name.
 
-If this variable is @code{nil}, or it fails to match a filename, the
-backup is made in the original file's directory.
+If this variable is @code{nil} (the default), or it fails to match a
+filename, the backup is made in the original file's directory.
 
 On MS-DOS filesystems without long names this variable is always
 ignored.
@@ -192,7 +192,7 @@ significance).  @xref{Saving Buffers}.
 
 @defopt backup-by-copying
 If this variable is non-@code{nil}, Emacs always makes backup files by
-copying.
+copying.  The default is @code{nil}.
 @end defopt
 
   The following three variables, when non-@code{nil}, cause the second
@@ -201,7 +201,7 @@ treatment of files that don't fall into the special cases.
 
 @defopt backup-by-copying-when-linked
 If this variable is non-@code{nil}, Emacs makes backups by copying for
-files with multiple names (hard links).
+files with multiple names (hard links).  The default is @code{nil}.
 
 This variable is significant only if @code{backup-by-copying} is
 @code{nil}, since copying is always used when that variable is
@@ -209,8 +209,9 @@ non-@code{nil}.
 @end defopt
 
 @defopt backup-by-copying-when-mismatch
-If this variable is non-@code{nil}, Emacs makes backups by copying in cases
-where renaming would change either the owner or the group of the file.
+If this variable is non-@code{nil} (the default), Emacs makes backups
+by copying in cases where renaming would change either the owner or
+the group of the file.
 
 The value has no effect when renaming would not alter the owner or
 group of the file; that is, for files which are owned by the user and
@@ -442,10 +443,11 @@ buffer-auto-save-file-name
 
 @deffn Command auto-save-mode arg
 When used interactively without an argument, this command is a toggle
-switch: it turns on auto-saving of the current buffer if it is off, and
-vice versa.  With an argument @var{arg}, the command turns auto-saving
-on if the value of @var{arg} is @code{t}, a nonempty list, or a positive
-integer.  Otherwise, it turns auto-saving off.
+switch: it turns on auto-saving of the current buffer if it is off,
+and vice versa.  When called from Lisp with no argument, it turns
+auto-saving on.  With an argument @var{arg}, it turns auto-saving on
+if the value of @var{arg} is @code{t}, a nonempty list, or a positive
+integer; otherwise, it turns auto-saving off.
 @end deffn
 
 @defun auto-save-file-name-p filename
@@ -755,3 +757,8 @@ This normal hook is run by @code{revert-buffer} after inserting
 the modified contents---but only if @code{revert-buffer-function} is
 @code{nil}.
 @end defvar
+
+@defvar revert-buffer-in-progress-p
+This variable is bound to a non-@code{nil} value by
+@code{revert-buffer} while it is working.
+@end defvar