(defun convert-standard-filename (filename)
"Convert a standard file's name to something suitable for the current OS.
-This function's standard definition is trivial; it just returns the argument.
-However, on some systems, the function is redefined
-with a definition that really does change some file names."
+This means to guarantee valid names and perhaps to canonicalize
+certain patterns.
+
+On Windows and DOS, replace invalid characters. On DOS, make
+sure to obey the 8.3 limitations. On Windows, turn Cygwin names
+into native names, and also turn slashes into backslashes if the
+shell requires it (see `w32-shell-dos-semantics')."
(let ((name
(save-match-data
(if (string-match "\\`/cygdrive/\\([a-zA-Z]\\)/" filename)