OutgoingMessageCorrelationData Property

Used by the sender of the request message to identify which request the response message is for when it is received.

Syntax

 mqtt.getOutgoingMessageCorrelationData(index, [callback])

Default Value

""

Callback

The 'callback' parameter specifies a function which will be called when the operation completes (or an error is encountered). If the 'callback' parameter is not specified, then the method will block and will not return until the operation completes (or an error is encountered).

The callback for the getOutgoingMessageCorrelationData([callback]) method is defined as:

function(err, data){ }

'err' is the error that occurred. If there was no error, then 'err' is 'null'.

'data' is the value returned by the method.

The callback for the setOutgoingMessageCorrelationData([callback]) method is defined as:

function(err){ }

'err' is the error that occurred. If there was no error, then 'err' is 'null'.

'err' has 2 properties which hold detailed information:

err.code
err.message

Remarks

Used by the sender of the request message to identify which request the response message is for when it is received.

Valid only for MQTT 5.

The index parameter specifies the index of the item in the array. The size of the array is controlled by the OutgoingMessageCount property.

This property is read-only and not available at design time.

Data Type

String