#### 21.1.1.7 Other Subclasses of Stream ¶

The class stream has a number of subclasses defined by this specification. Figure 21–5 shows some information about these subclasses.

      Class                Related Operators
      broadcast-stream     make-broadcast-stream
                           broadcast-stream-streams
      concatenated-stream  make-concatenated-stream
                           concatenated-stream-streams
      echo-stream          make-echo-stream
                           echo-stream-input-stream
                           echo-stream-output-stream
      string-stream        make-string-input-stream
                           with-input-from-string
                           make-string-output-stream
                           with-output-to-string
                           get-output-stream-string
      synonym-stream       make-synonym-stream
                           synonym-stream-symbol
      two-way-stream       make-two-way-stream
                           two-way-stream-input-stream
                           two-way-stream-output-stream

      Figure 21–5: Defined Names related to Specialized Streams