stream-element-type

stream-element-type stream → typespec

stream — a stream.

typespec — a type specifier.

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.

;; 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))

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