sub functionname {
    my ($string_param, $array_param_ref, $other_string_param) = @_;
    my @array_param = @$array_param_ref;
    # do something with parameters, return values
}

##</code><code>##

sub functionname{
    my ($string_param, $other_string_param, @array_param) = @_;
    # do something with parameters, return values
}