Streams

Echo-streams and concatenated-streams are not available. Predefined streams are following:

*standard-input*

stdin fd=0

*standard-output*

stdout fd=1

*error-output*

stderr fd=2 bufsize=1

*terminal-io*

two-way stream made of *standard-input* and *standard-output*

  streamp object [function]

• Any object created from  stream,  io-stream, or their subclasses returns T.

  input-stream-p object [function]

• T if object is a stream and capable of reading.

  output-stream-p object [function]

• T if object is a stream and capable of writing.

  io-stream-p object [function]

• T if object is a two-way stream.

 

• Open makes a stream associated with a file designated by path. path may either be a string or a pathname. Direction should be one of :input, :output or :io. Several open options, :append, :new-version, :overwrite, :error and nil are allowed for :if-exists parameter. However, this parameter is ignored when direction is :input. Alternatives for :if-does-not-exist are :error, :create and nil. :new-version, :rename and :supersede are not recognized. By default, the file is overwritten if direction is either :output or :io when the file exists. For :input files, an error is reported when the file does not exist. To know the existence of a file, probe-file can be used. Default value for buffer-size is 512 bytes, and #O644 for :permission. SunOS4 allows to open as many as sixty files at the same time.

  with-open-file (svar path . open-options) &rest forms [macro]

• A file named path is opened with open-options and the stream is bound to svar. Then forms are evaluated. The stream is automatically closed when evaluation of forms finishes or exits with throw, return-from or error. With-open-file is a macro defined by unwind-protect with close in its clean-up forms.

  close stream [function]

• closes the stream, and returns T if successful. The stream may have already been closed, in which case nil is returned. Streams are automatically closed by GC if there is no reference to that stream object.

  make-string-input-stream string [function]

• makes an input stream from a string.

  make-string-output-stream size [function]

• makes an output stream to a string of size length. Actually, the length is automatically expanded, so size is only advisory information to allocate string at initialization.

  get-output-stream-string string-stream [function]

• gets a string out of a string-stream.

  make-broadcast-stream &rest output-streams [function]

• makes a broad-cast stream which forwards all the messages written to this stream to each of output-streams.