send_describe_portal (PGconn)

    /*
     * call-seq:
     *    conn.send_describe_portal( portal_name ) -> nil
     *
     * Asynchronously send _command_ to the server. Does not block.
     * Use in combination with +conn.get_result+.
     */
    static VALUE
    pgconn_send_describe_portal(VALUE self, VALUE portal)
    {
            VALUE error;
            PGconn *conn = get_pgconn(self);
            /* returns 0 on failure */
            if(PQsendDescribePortal(conn,StringValuePtr(portal)) == 0) {
                    error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
                    rb_iv_set(error, "@connection", self);
                    rb_exc_raise(error);
            }
            return Qnil;
    }