Info Catalog elisp: Saving Buffers elisp: Files elisp: Writing to Files

elisp: Reading from Files

 
 24.3 Reading from Files
 =======================
 
 To copy the contents of a file into a buffer, use the function
 ‘insert-file-contents’.  (Don’t use the command ‘insert-file’ in a Lisp
 program, as that sets the mark.)
 
  -- Function: insert-file-contents filename &optional visit beg end
           replace
      This function inserts the contents of file FILENAME into the
      current buffer after point.  It returns a list of the absolute file
      name and the length of the data inserted.  An error is signaled if
      FILENAME is not the name of a file that can be read.
 
      This function checks the file contents against the defined file
      formats, and converts the file contents if appropriate and also
      calls the functions in the list ‘after-insert-file-functions’.
      Format Conversion.  Normally, one of the functions in the
      ‘after-insert-file-functions’ list determines the coding system
      (Coding Systems) used for decoding the file’s contents,
      including end-of-line conversion.  However, if the file contains
      null bytes, it is by default visited without any code conversions.
      inhibit-null-byte-detection Lisp and Coding Systems.
 
      If VISIT is non-‘nil’, this function additionally marks the buffer
      as unmodified and sets up various fields in the buffer so that it
      is visiting the file FILENAME: these include the buffer’s visited
      file name and its last save file modtime.  This feature is used by
      ‘find-file-noselect’ and you probably should not use it yourself.
 
      If BEG and END are non-‘nil’, they should be numbers that are byte
      offsets specifying the portion of the file to insert.  In this
      case, VISIT must be ‘nil’.  For example,
 
           (insert-file-contents filename nil 0 500)
 
      inserts the first 500 characters of a file.
 
      If the argument REPLACE is non-‘nil’, it means to replace the
      contents of the buffer (actually, just the accessible portion) with
      the contents of the file.  This is better than simply deleting the
      buffer contents and inserting the whole file, because (1) it
      preserves some marker positions and (2) it puts less data in the
      undo list.
 
      It is possible to read a special file (such as a FIFO or an I/O
      device) with ‘insert-file-contents’, as long as REPLACE and VISIT
      are ‘nil’.
 
  -- Function: insert-file-contents-literally filename &optional visit
           beg end replace
      This function works like ‘insert-file-contents’ except that it does
      not run ‘find-file-hook’, and does not do format decoding,
      character code conversion, automatic uncompression, and so on.
 
    If you want to pass a file name to another process so that another
 program can read the file, use the function ‘file-local-copy’; see 
 Magic File Names.
 

Info Catalog elisp: Saving Buffers elisp: Files elisp: Writing to Files