sub large_array_ref {
  my $large_array_ref = [];
  ...populate @$large_array_ref...
  return $large_array_ref;
}

my $c = large_array_ref();

$c->[ ... ];

##</code><code>##

sub large_array_ref {
  my $large_array_ref = shift;
  ...populate @$large_array_ref...
  return;
}

large_array_ref( \my @c );

$c[ ... ];

##</code><code>##

populateThingArray( \my @c );

$c[ ... ];