* processes.texi (Synchronous Processes): New defvar process-file-side-effects.

doc/lispref/ChangeLog

+2009-08-25  Michael Albinus  <michael.albinus@gmx.de>
+
+	* processes.texi (Synchronous Processes): New defvar
+	process-file-side-effects.
+
 2009-08-25  Glenn Morris  <rgm@gnu.org>
 
 	* display.texi (Fontsets): Fix typo.

doc/lispref/processes.texi

@@ -404,6 +404,19 @@ names as relative to @code{default-directory}.  The function
 file names.
 @end defun
 
+@defvar process-file-side-effects
+This variable indicates, whether a call of @code{process-file} changes
+remote files.
+
+Per default, this variable is always set to @code{t}, meaning that a
+call of @code{process-file} could potentially change any file on a
+remote host.  When set to @code{nil}, a file handler could optimize
+its behaviour with respect to remote file attributes caching.
+
+This variable should never be changed by @code{setq}.  Instead of, it
+shall be set only by let-binding.
+@end defvar
+
 @defun call-process-region start end program &optional delete destination display &rest args
 This function sends the text from @var{start} to @var{end} as
 standard input to a process running @var{program}.  It deletes the text