IncomingMessageCorrelationData Property
Used by the sender of the request message to identify which request the response message is for when it is received.
Syntax
mqtt.getIncomingMessageCorrelationData(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 getIncomingMessageCorrelationData([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 setIncomingMessageCorrelationData([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 IncomingMessageCount property.
This property is read-only and not available at design time.
Data Type
String