>perl -wMstrict -le
"my $s = 'PppP';
 ;;
 my $search = qr{ (?i) pp }xms;
 my $count = my @captures = $s =~ m{ (?= ($search)) }xmsg;
 ;;
 print qq{found $count: (@captures)};
"
found 3: (Pp pp pP)