sub RLS_ropen($) {
    (@_ == 1) || die "RLS_ropen called w/ invalid argument list: ".scalar(@_)." params instead of 1";
    my $name = $_[0];

    unless ( $name ) {
        # invalid - null or empty file name
        return "";
    }

    unless ( -e $name && -r $name ) {
        # file doesn't exits or is unreadable
        return "";
    }

    open( my $dbh, "< $name");
    return $dbh;
}   # end RLS_ropen