+ \(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.")
+ (pathname
+ (sb-ext:native-namestring (translate-logical-pathname filename)
+ :as-file t))
+ (string
+ filename)
+ (stream
+ (filename (pathname filename))))
+
+(define-designator file-descriptor (fixnum (integer 32))
+ ("A FIXNUM designating a native file descriptor.
+
+SB-SYS:MAKE-FD-STREAM can be used to construct a FILE-STREAM associated with a
+native file descriptor.
+
+Note that mixing I/O operations on a FILE-STREAM with operations directly on its
+descriptor may produce unexpected results if the stream is buffered."
+ "Designator for a FILE-DESCRIPTOR: either a fixnum designating itself, or
+a FILE-STREAM designating the underlying file-descriptor."
+ "Converts FILE-DESCRIPTOR-DESIGNATOR into a FILE-DESCRIPTOR.")
+ (file-stream
+ (sb-sys:fd-stream-fd file-descriptor))
+ (fixnum
+ file-descriptor))
+
+(define-designator sap-or-nil (sb-sys:system-area-pointer sb-sys:system-area-pointer)
+ ()