#### 21.1.3 Stream Arguments to Standardized Functions

The operators in Figure 21–7 accept stream arguments that might be either open or closed streams.

      broadcast-stream-streams     file-author       pathnamep
      close                        file-namestring   probe-file
      compile-file                 file-write-date   rename-file
      compile-file-pathname        host-namestring   streamp
      concatenated-stream-streams  load              synonym-stream-symbol
      delete-file                  logical-pathname  translate-logical-pathname
      directory                    merge-pathnames   translate-pathname
      directory-namestring         namestring        truename
      dribble                      open              two-way-stream-input-stream
      echo-stream-input-stream     open-stream-p     two-way-stream-output-stream
      echo-stream-ouput-stream     parse-namestring  wild-pathname-p
      ed                           pathname          with-open-file
      enough-namestring            pathname-match-p

            Figure 21–7: Operators that accept either Open or Closed Streams

The operators in Figure 21–8 accept stream arguments that must be open streams.

     clear-input              output-stream-p         read-char-no-hang
     clear-output             peek-char               read-delimited-list
     file-length              pprint                  read-line
     file-position            pprint-fill             read-preserving-whitespace
     file-string-length       pprint-indent           stream-element-type
     finish-output            pprint-linear           stream-external-format
     force-output             pprint-logical-block    terpri
     format                   pprint-newline          unread-char
     fresh-line               pprint-tab              with-open-stream
     get-output-stream-string pprint-tabular          write
     input-stream-p           prin1                   write-byte
     interactive-stream-p     princ                   write-char
     listen                   print                   write-line
     make-broadcast-stream    print-object            write-string
     make-concatenated-stream print-unreadable-object y-or-n-p
     make-echo-stream         read                    yes-or-no-p
     make-synonym-stream      read-byte
     make-two-way-stream      read-char

                 Figure 21–8: Operators that accept Open Streams only