Info Catalog elisp: File Name Completion elisp: File Names

elisp: Standard File Names

 
 24.8.7 Standard File Names
 --------------------------
 
 Sometimes, an Emacs Lisp program needs to specify a standard file name
 for a particular use—typically, to hold configuration data specified by
 the current user.  Usually, such files should be located in the
 directory specified by ‘user-emacs-directory’, which is ‘~/.emacs.d’ by
 default (Init File).  For example, abbrev definitions are stored
 by default in ‘~/.emacs.d/abbrev_defs’.  The easiest way to specify such
 a file name is to use the function ‘locate-user-emacs-file’.
 
  -- Function: locate-user-emacs-file base-name &optional old-name
      This function returns an absolute file name for an Emacs-specific
      configuration or data file.  The argument ‘base-name’ should be a
      relative file name.  The return value is the absolute name of a
      file in the directory specified by ‘user-emacs-directory’; if that
      directory does not exist, this function creates it.
 
      If the optional argument OLD-NAME is non-‘nil’, it specifies a file
      in the user’s home directory, ‘~/OLD-NAME’.  If such a file exists,
      the return value is the absolute name of that file, instead of the
      file specified by BASE-NAME.  This argument is intended to be used
      by Emacs packages to provide backward compatibility.  For instance,
      prior to the introduction of ‘user-emacs-directory’, the abbrev
      file was located in ‘~/.abbrev_defs’.  Here is the definition of
      ‘abbrev-file-name’:
 
           (defcustom abbrev-file-name
             (locate-user-emacs-file "abbrev_defs" ".abbrev_defs")
             "Default name of file from which to read abbrevs."
             ...
             :type 'file)
 
    A lower-level function for standardizing file names, which
 ‘locate-user-emacs-file’ uses as a subroutine, is
 ‘convert-standard-filename’.
 
  -- Function: convert-standard-filename filename
      This function returns a file name based on FILENAME, which fits the
      conventions of the current operating system.
 
      On GNU and Unix systems, this simply returns FILENAME.  On other
      operating systems, it may enforce system-specific file name
      conventions; for example, on MS-DOS this function performs a
      variety of changes to enforce MS-DOS file name limitations,
      including converting any leading ‘.’ to ‘_’ and truncating to three
      characters after the ‘.’.
 
      The recommended way to use this function is to specify a name which
      fits the conventions of GNU and Unix systems, and pass it to
      ‘convert-standard-filename’.
 

Info Catalog elisp: File Name Completion elisp: File Names