1 files changed, 7 insertions, 5 deletions

diff --git a/doc/lispref/files.texi b/doc/lispref/files.texi
index 735e08eb324..edfb045a795 100644
--- a/doc/lispref/files.texi
+++ b/doc/lispref/files.texi
@@ -2421,11 +2421,13 @@ the file, which in some cases may cause a security hole.
   This section describes low-level subroutines for completing a file
 name.  For higher level functions, see @ref{Reading File Names}.
 
-@defun file-name-all-completions partial-filename directory
-This function returns a list of all possible completions for a file
-whose name starts with @var{partial-filename} in directory
-@var{directory}.  The order of the completions is the order of the files
-in the directory, which is unpredictable and conveys no useful
+@defun file-name-all-completions partial-filename directory &optional predicate
+This function returns a list of all possible completions for a file in
+directory @var{directory} whose name starts with
+@var{partial-filename} and for which @var{predicate} (called with the
+filename) returns non-nil. If @var{predicate} is nil (the default), it
+is ignored. The order of the completions is the order of the files in
+the directory, which is unpredictable and conveys no useful
 information.
 
 The argument @var{partial-filename} must be a file name containing no