my $variable = my_subroutine(\@my_array);
sub my_subroutine
{
	my $array = shift;
	# involves dereferencing the array_reference
	...
	
	return(\$variable);
}

##</code><code>##

my $variable = my_subroutine(\$array_start_idx, \$array_end_idx);
sub my_subroutine
{
	my $start_idx = shift;
	my $end_idx = shift;
	# involves accessong the global array using the indices passed
	...
	
	return(\$variable);
}