@end example
@end defun
-@defun file-name-completion filename directory
+@defun file-name-completion filename directory &optional predicate
This function completes the file name @var{filename} in directory
@var{directory}. It returns the longest prefix common to all file names
-in directory @var{directory} that start with @var{filename}.
+in directory @var{directory} that start with @var{filename}. If
+@var{predicate} is non-@code{nil} then it ignores possible completions
+that don't satisfy @var{predicate}, after calling that function
+with one argument, the expanded absolute file name.
If only one match exists and @var{filename} matches it exactly, the
function returns @code{t}. The function returns @code{nil} if directory