mysub(
   FH => *INPUT,
   arr1 => \@arr1,
   arr2 => \@arr2
   );

sub mysub
{
   my %args = @_;

   my $first = $args{arr1}->[0];

}

##</code><code>##

sub named_params_with_defaults
   {
      my %args = (
         one => 'default value',
         two => 'default value',
         @_, # Will override the above values.
      );
   }

   named_params_with_defaults(
      one => "override arg 'one'"
   );