stream-element-type (ANSI and GNU Common Lisp Document)

Next: streamp, Previous: open-stream-p, Up: Streams Dictionary

#### 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.