(PECL getdns >= 0.10.0)
php_getdns_context_set_limit_outstanding_queries — Set the limit for the number of oustanding queries.
This function sets an upper limit on the number of outstanding DNS queries. The getdns library will block itself from sending more queries if it is about to exceed this value, and instead keep those queries in an internal queue.
The previously created DNS context that is to be used with this request.
An integer value between 0 and 65535 inclusive that represents the upper limit on the number of outstanding DNS queries. A value of 0 (zero) indicates that no limit should be set.
This function returns an integer response code. GETDNS_RETURN_GOOD indicates successful completion.