?- open(f,write,S,[type(binary)]),put_byte(S,0xff),close(S). % f : file with invalid UTF-8
S = '$dropped_value'
| S = ... . % another value would be just as fine
?- open(f,read,S),peek_char(S,C).
S = '$stream'(0x55d200e3b390), C = end_of_file, unexpected.
representation_error(character). % expected, but not found
?- open(f,read,S),get_char(S,C).
error(syntax_error(invalid_data),get_char/2), unexpected.
representation_error(character). % expected, but not found