Improve documentation of functions that change files

* doc/lispref/files.texi (Changing Files): Document that these
functions signal an error on failure.

diff --git a/doc/lispref/files.texi b/doc/lispref/files.texi
index db2ecc08f95e4ddf7668fd38007d7d402be65ea2..4d2761ed4197ee1445b26afbf339799066c0cec5 100644 (file)
--- a/doc/lispref/files.texi
+++ b/doc/lispref/files.texi
@@ -1481,7 +1481,10 @@ in @code{exec-path}, and tries all the file-name extensions in
 @cindex setting modes of files
 
   The functions in this section rename, copy, delete, link, and set
-the modes (permissions) of files.
+the modes (permissions) of files.  They all signal a @code{file-error}
+error if they fail to perform their function, reporting the
+system-dependent error message that describes the reason for the
+failure.
 
   In the functions that have an argument @var{newname}, if a file by the
 name of @var{newname} already exists, the actions taken depend on the