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file-stream

file-stream System Class

Class Precedence List:

file-stream, stream, t

Description:

An object of type file-stream is a stream the direct source or sink of which is a file. Such a stream is created explicitly by open and with-open-file, and implicitly by functions such as load that process files.

See Also:

load, open, with-open-file

Expanded Reference: file-stream​

Overview​

file-stream is a system class for streams whose direct source or sink is a file. Such streams are created by open and with-open-file.

Type Check​

(with-open-file (s "/tmp/cl-fs-test.txt"
                   :direction :output :if-exists :supersede)
  (typep s 'file-stream))
=> T

Distinguishing from String Streams​

String streams are not file streams.

(typep (make-string-output-stream) 'file-stream)
=> NIL

Class Hierarchy​

(subtypep 'file-stream 'stream)
=> T
=> T

Created by open and with-open-file​

Both open and with-open-file produce file streams.

(let ((s (open "/tmp/cl-fs-test.txt" :direction :probe)))
  (prog1 (typep s 'file-stream)
    (close s)))
=> T