use warnings;
use strict;

my ($len, @temp) = getlists();
my @a = @temp[0..$len-1];
my @b = @temp[$len..@temp-1];
undef @temp;

print "@a\n@b\n";

sub getlists {
  my @foo = (1,2,3);
  my @bar = (4,5,6);
  return scalar(@foo), @foo, @bar;
}