.. efun:: int file_size(string file)
  :include: <files.h>

  :return: - :macro:`FSIZE_NOFILE` (-1) : indicates that the file either does not exist, or that it is not readable for the calling object/user.
           - :macro:`FSIZE_DIR` (-2) : indicates that it is a directory.

  Returns the size of the file in bytes.

  .. todo:: above demonstrates use of return field.

  .. seealso:: :efun:`write_file`, :efun:`write_bytes`, :efun:`read_file`, :efun:`read_bytes`, :efun:`get_dir`