my $par1 = $posted_value;        # not marked as utf8 yet
  my $par2 = $already_known_value; # marked as utf8
  my $res  = 0;

##</code><code>##

  # code1 - compare octets
  $par1 = Encode::encode_utf8($par1) if Encode::is_utf8($par1);
  $par2 = Encode::encode_utf8($par2) if Encode::is_utf8($par2);
  $res = ($par1 eq $par2) ? 1 : 0;
  # $res now contain 1 - $par1 and $par2 are equal

##</code><code>##

  # code2 - compare strings
  $par1 = Encode::decode_utf8($par1) if !Encode::is_utf8($par1);
  $par2 = Encode::decode_utf8($par2) if !Encode::is_utf8($par2);
  $res = ($par1 eq $par2) ? 1 : 0;
  # $res now contain 0 - $par1 and $par2 are not equal