if (""->is_file ()) ...                                                        /* "ERR_EMPTY_FILE_NAME" */

if (""->is_directory ()) ...                                                   /* "ERR_EMPTY_DIRECTORY_NAME" */

if ("?*><"->is_file ()) ...                                                    /* "ERR_INCORRECT_FILE_NAME" */

if ("?*><"->is_directory ()) ...                                               /* "ERR_INCORRECT_DIRECTORY_NAME" */
