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(librep.info)Functions on File Objects

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Functions on File Objects
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 - Function: seek-file file #!optional offset where
     When called as `(seek-file FILE)', returns the distance in bytes
     from the start of the file that the next character would be read
     from.

     When called as `(seek-file FILE OFFSET [WHERE])' alters the
     position from which the next byte will be read. WHERE can be one
     of the values:

    `()'
          OFFSET bytes after the current position.

    `start'
          OFFSET bytes after the beginning of the file.

    `end'
          OFFSET bytes before the end of the file.

     Note that not all files may be seekable; if `(seek-file FILE)'
     returns false, indicating that the current position is unknown,
     any attempts to set the current position will also fail.

 - Function: flush-file file
     This function flushes any buffered output to the file object FILE
     to disk.

 - Function: file-binding file
     Returns the name of the file which the file object FILE is
     currently bound to. Returns false if the file is currently unbound
     (i.e. `close-file' was called on it).

   The next three functions are used when non-local files are being
accessed. See Note: File Handlers for more details.

 - Function: file-bound-stream file
     If the file object FILE doesn't refer to a file in the local
     filing system, return the stream that it is bound to (allowing the
     file's contents to be accessed), this may or may not be another
     file object.

 - Function: file-handler-data file
     Return the file-handler-specific data associated with the file
     object FILE.

 - Function: set-file-handler-data file data
     Set the handler-specific data of file object FILE to DATA.  This
     should only be done by the handler owning the file.

   It's also possible to register a callback function to be invoked when
input is available on a file,

 - Function: set-input-handler local-file function
     Arrange for FUNCTION to be called whenever pending input is
     available on LOCAL-FILE, a file object bound to a file in the
     local file space.

     Note that this makes LOCAL-FILE subsequently do non-blocking input.

     This function is normally only useful when LOCAL-FILE represents a
     pipe or socket.