MQTT_DeserializeAck

Deserialize an MQTT CONNACK, SUBACK, UNSUBACK, PUBACK, PUBREC, PUBREL, PUBCOMP, or PINGRESP.

MQTTStatus_t MQTT_DeserializeAck( const MQTTPacketInfo_t * pIncomingPacket,
                                  uint16_t * pPacketId,
                                  bool * pSessionPresent );

Parameters

[in]	pIncomingPacket	MQTTPacketInfo_t containing the buffer.
[out]	pPacketId	The packet ID of obtained from the buffer. Not used in CONNACK or PINGRESP.
[out]	pSessionPresent	Boolean flag from a CONNACK indicating present session.

Returns

MQTTBadParameter, MQTTBadResponse, MQTTServerRefused, or MQTTSuccess.

Example

// Variables used in this example.
MQTTStatus_t status;
MQTTPacketInfo_t incomingPacket;
// Used for SUBACK, UNSUBACK, PUBACK, PUBREC, PUBREL, and PUBCOMP.
uint16_t packetId;
// Used for CONNACK.
bool sessionPresent;
 
// Receive an incoming packet and populate all fields. The details are out of scope
// for this example.
receiveIncomingPacket( &incomingPacket );
 
// Deserialize ack information if the incoming packet is not a publish.
if( ( incomingPacket.type & 0xF0 ) != MQTT_PACKET_TYPE_PUBLISH )
{
     status = MQTT_DeserializeAck( &incomingPacket, &packetId, &sessionPresent );
     if( status == MQTTSuccess )
     {
         // The packet ID or session present flag information is available. For
         // ping response packets, the only information is the status code.
     }
}