Untested: 
use 5.010;
my $t = $s1 ^ $s2;
my ($f) = $t =~ /^(\x{00}*)/;
say length $f;

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In reply to Re: If there a way to find the location of the first difference between two strings? by JavaFan
in thread If there a way to find the location of the first difference between two strings? by flexvault

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