/*
 * call-seq:
 *    conn.error_message -> String
 *
 * Returns the error message about connection.
 */
static VALUE
pgconn_error_message(VALUE self)
{
        char *error = PQerrorMessage(get_pgconn(self));
        if (!error) return Qnil;
        return rb_tainted_str_new2(error);
}