$ LC_CTYPE='en_US.UTF-8' perl -Mlocale -le'my $ch = chr(0x2660); print length($ch);'
1
$ LC_CTYPE='en_US'       perl -Mlocale -le'my $ch = chr(0x2660); print length($ch);'
1

$ LC_CTYPE='en_US.UTF-8' perl -Mlocale -MEncode -le'my $ch = chr(0x2660); my $bytes = encode("utf-8", $ch); print length($bytes);'
3
$ LC_CTYPE='en_US'       perl -Mlocale -MEncode -le'my $ch = chr(0x2660); my $bytes = encode("utf-8", $ch); print length($bytes);'
3