Mqtt Toolkit - @octave_mqtt/subscribe

: subs = subscribe (obj, topic)

: subs = subscribe (obj, topic, [propname, propvalue ....])

Subscribe to a topic

Inputs

obj: A previously created octave_mqtt object
topic: String topic to subscribe to.
propname, propvalue: Optional property name / value pairs.

Known property name / value pairs:

QualityOfService

Numeric QualityOfService [0-2] (default 0)

Callback

Callback function name or handle (default "")

If provided, the callback will be called with the topic name and message as arguments.

Outputs

subs: a list of current subscriptions for this client.

Examples

Subscribe to topic ’Test’:

 
 client = mqttclient("tcp://127.0.0.1");
 subs = subscribe(client, "Test");

Subscribe to topic ’Test’ and display any changed via callback:

 
 # define simple function to show callback data
 function showmessage(t,v), printf("Topic: %s Message: %s\n", t, v); endfunction

 client = mqttclient("tcp://127.0.0.1");
 subs = subscribe(client, "Test", "Callback", @showmessage);

See also: mqttclient, unsubscribe.