MQTT_SerializeAck

Serialize an MQTT PUBACK, PUBREC, PUBREL, or PUBCOMP into the given buffer.

MQTTStatus_t MQTT_SerializeAck( const MQTTFixedBuffer_t * pFixedBuffer,
                                uint8_t packetType,
                                uint16_t packetId );

Parameters

[out]	pFixedBuffer	Buffer for packet serialization.
[in]	packetType	Byte of the corresponding packet fixed header per the MQTT spec.
[in]	packetId	Packet ID of the publish.

Returns

MQTTBadParameter, MQTTNoMemory, or MQTTSuccess.

Example

// Variables used in this example.
MQTTStatus_t status;
MQTTFixedBuffer_t fixedBuffer;
uint8_t buffer[ BUFFER_SIZE ];
uint16_t packetId;
uint8_t packetType;
 
fixedBuffer.pBuffer = buffer;
fixedBuffer.size = BUFFER_SIZE;
// The fixed buffer must be large enough to hold 4 bytes.
assert( BUFFER_SIZE >= MQTT_PUBLISH_ACK_PACKET_SIZE );
 
// The packet ID must be the same as the original publish packet.
packetId = publishPacketId;
 
// The byte representing a packet of type ACK. This function accepts PUBACK, PUBREC, PUBREL, or PUBCOMP.
packetType = MQTT_PACKET_TYPE_PUBACK;
 
// Serialize the publish acknowledgment into the fixed buffer.
status = MQTT_SerializeAck( &fixedBuffer, packetType, packetId );
 
if( status == MQTTSuccess )
{
     // The publish acknowledgment can now be sent to the broker.
}