$\ = "\n"; utf8::downgrade $dn = chr(0xC9); utf8::upgrade $up = chr(0xC9); # <5.10 >=5.10 print pack('A', $dn) eq chr(0xC9) ?1:0; # 1 1 print pack('A', $up) eq chr(0xC9) ?1:0; # 0 1 print $dn =~ /\w/ ?1:0; # 0 print $up =~ /\w/ ?1:0; # 1