+(define-designator filename (string c-string)
+ ("A STRING designating a filename in native namestring syntax.
+
+Note that native namestring syntax is distinct from Lisp namestring syntax:
+
+ \(pathname \"/foo*/bar\")
+
+is a wild pathname with a pattern-matching directory component.
+SB-EXT:PARSE-NATIVE-NAMESTRING may be used to construct Lisp pathnames that
+denote POSIX filenames as understood by system calls, and
+SB-EXT:NATIVE-NAMESTRING can be used to coerce them into strings in the native
+namestring syntax.
+
+Note also that POSIX filename syntax does not distinguish the names of files
+from the names of directories: in order to parse the name of a directory in
+POSIX filename syntax into a pathname MY-DEFAULTS for which
+
+ \(merge-pathnames (make-pathname :name \"FOO\" :case :common)
+ my-defaults)
+
+returns a pathname that denotes a file in the directory, supply a true
+:AS-DIRECTORY argument to SB-EXT:PARSE-NATIVE-NAMESTRING. Likewise, to supply
+the name of a directory to a POSIX function in non-directory syntax, supply a
+true :AS-FILE argument to SB-EXT:NATIVE-NAMESTRING."
+ "Designator for a FILENAME: a STRING designating itself, or a
+designator for a PATHNAME designating the corresponding native namestring."
+ "Converts FILENAME-DESIGNATOR into a FILENAME.")