Return codes used for MyQttOnPublish handler.

Enumerator
MYQTT_PUBLISH_OK 

Reports to the engine that the publish operation can continue.

MYQTT_PUBLISH_DISCARD 

Reports to the engine that the message must be discarded and to skip any publish/relay.

Note MQTT protocol does not have any support to notify a PUBLISH denial. In this case, the engine will just unref the message without taking any further action (including publishing it to subscribers).

MYQTT_PUBLISH_CONN_CLOSE 

Close publisher's connection.

MYQTT_PUBLISH_DUNNO 

Publish autorization code that means neutral result: it means the server will take no action and a further rule will have the decide (or a user/server configuration).