21.2.12 stream-element-type [Function]

stream-element-type stream ⇒ typespec

Arguments and Values::

stream—a stream.

typespec—a type specifier.

Description::

stream-element-type returns a type specifier that indicates the types of objects that may be read from or written to stream.

Streams created by open have an element type restricted to integer or a subtype of type character.

Examples::

;; Note that the stream must accomodate at least the specified type,
;; but might accomodate other types.  Further note that even if it does
;; accomodate exactly the specified type, the type might be specified in
;; any of several ways.
 (with-open-file (s "test" :element-type '(integer 0 1)
                           :if-exists :error
                           :direction :output)
   (stream-element-type s))
⇒  INTEGER
OR⇒ (UNSIGNED-BYTE 16)
OR⇒ (UNSIGNED-BYTE 8)
OR⇒ BIT
OR⇒ (UNSIGNED-BYTE 1)
OR⇒ (INTEGER 0 1)
OR⇒ (INTEGER 0 (2))

Exceptional Situations::

Should signal an error of type type-error if stream is not a stream.