21.2.9 input-stream-p, output-stream-p [Function]

input-stream-p stream ⇒ generalized-boolean

output-stream-p stream ⇒ generalized-boolean

Arguments and Values::

stream—a stream.

generalized-boolean—a generalized boolean.

Description::

input-stream-p returns true if stream is an input stream; otherwise, returns false.

output-stream-p returns true if stream is an output stream; otherwise, returns false.

Examples::

 (input-stream-p *standard-input*) ⇒  true
 (input-stream-p *terminal-io*) ⇒  true
 (input-stream-p (make-string-output-stream)) ⇒  false

 (output-stream-p *standard-output*) ⇒  true
 (output-stream-p *terminal-io*) ⇒  true
 (output-stream-p (make-string-input-stream "jr")) ⇒  false

Exceptional Situations::

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