our $var;
local $var;

##</code><code>##

sub sum {
    our @a
    local *a = shift;
    my $total = 0;
    $total += $a[ $_ ] for 0 .. $#a;
    return $total;
}

my @data = getNums();

my $sum = sum( \@data );

##</code><code>##

sub sum {
    my $aref = shift;
    my $total = 0;
    $total += $aref->[ $_ ] for 0 .. $#{ $aref };
    return $total;
}

my @data = getNums();

my $sum = sum( \@data );