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#### 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.