onMessageIn (event)

Fired when an incoming message has been received and/or fully acknowledged.


- (void)onMessageIn:(int)packetId :(NSString*)topic :(int)QOS :(NSData*)message :(BOOL)retained :(BOOL)duplicate;
func onMessageIn(_ packetId: Int32, _ topic: String, _ QOS: Int32, _ message: Data, _ retained: Bool, _ duplicate: Bool)


The MessageIn event fires once for each incoming message either immediately after it is received (QoS 0), or after it has been fully acknowledged (QoS 1 and 2).

  • PacketId: The message packet Id. This will always be -1 if QOS is 0.
  • Topic: The message's topic string.
  • QOS: The message's QoS level.
  • Message: The message data.
  • Retained: Whether or not this message was received as a result of subscribing to a topic.
  • Duplicate: Whether or not the server has indicated that this message is a duplicate of another message sent previously.

Refer to MessageAck for more information about QoS 1 and 2 message processing steps.

// MessageIn event handler.
mqtt1.OnMessageIn += (s, e) => {
  Console.WriteLine("Received message from topic '" + e.Topic + "' with QoS " + e.QOS + ":");

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IPWorks MQ 2020 iOS Edition - Version 20.0 [Build 8162]