c:\@Work\Perl\monks>perl -wMstrict -le
"my $non_vowel = qr{ [^AEIOUaeiou] }xms;
 ;;
 my $s = 'aePDQioVWXua';
 ;;
 print 'offset of first non-vowel: ', $s =~ m{ (?= $non_vowel) }xmsg ? pos($s) : 'none';
 print 'offset of last non-vowel: ', $s =~ m{ .* (?= $non_vowel) }xmsg ? pos($s) : 'none';
 ;;
 $s = 'aei';
 print 'offset of first non-vowel: ', $s =~ m{ (?= $non_vowel) }xmsg ? pos($s) : 'none';
"
offset of first non-vowel: 2
offset of last non-vowel: 9
offset of first non-vowel: none