result = argv[optind];
  len = dir_len (result);

  if (! len)
    {
      result = ˙ // сие определено как static char const dot = '.';
      len = 1;
    }

  fwrite (result, 1, len, stdout);
  putchar ('\n');

  exit (EXIT_SUCCESS);

/* Return the length of `dirname (FILE)', or zero if FILE is
   in the working directory.  Works properly even if
   there are trailing slashes (by effectively ignoring them).  */
size_t
dir_len (char const *file)
{
  size_t prefix_length = FILE_SYSTEM_PREFIX_LEN (file); // а это всегда раскрывается в 0. Зачем -- неведомо.
  size_t length;

  /* Strip the basename and any redundant slashes before it.  */
  for (length = base_name (file) - file;  prefix_length < length;  length--)
    if (! ISSLASH (file[length - 1]))
      return length;

  /* But don't strip the only slash from "/".  */
  return prefix_length + ISSLASH (file[prefix_length]);
}