>perl -le "$s=qq{\0}; $,=q{, }; print length($s), qq{[$s]}, $s eq chr(0) ?1:0"
1, [ ], 1

>perl -le "$s=q{\0}; $,=q{, }; print length($s), qq{[$s]}, $s eq chr(0) ?1:0"
2, [\0], 0