4 The COMMON-LISP Package

output-stream-p

Generic Function

Summary

A generic function that determines if an object is an output stream.

Package

common-lisp

Signature

output-stream-p stream => result

Arguments

stream: A stream.

Values

result: A generalized boolean.

Description

The predicateoutput-stream-p is implemented as a generic function. The default method returnst if stream is an output stream. If the user wants to implement a stream with no inherent directionality (and thus does not includefundamental-input-stream orfundamental-output-stream) but for which the directionality depends on the instance, then a method should be provided foroutput-stream-p.