c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = '    a     ';
 ;;
 $s =~ m{ \S }xms;
 print $-[0];
"
4

##</code><code>##

c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = 'xyzzyBARxkcdFOOyz';
 ;;
 my $vowel = qr{ [AEIOUaeiou] }xms;
 ;;
 print qq{offset of first vowel: }, $s =~ m{ ($vowel) }xms ? $-[1] : 'none';
 ;;
 print qq{offset of last vowel: }, $s =~ m{ .* ($vowel) }xms ? $-[1] : 'none';
 ;;
 print qq{offset of first vowel: }, 'XYZ' =~ m{ ($vowel) }xms ? $-[1] : 'none';
"
offset of first vowel: 6
offset of last vowel: 14
offset of first vowel: none