MQTT_InitStatefulQoS

Initialize an MQTT context for QoS > 0.

MQTTStatus_t MQTT_InitStatefulQoS( MQTTContext_t * pContext,
                                   MQTTPubAckInfo_t * pOutgoingPublishRecords,
                                   size_t outgoingPublishCount,
                                   MQTTPubAckInfo_t * pIncomingPublishRecords,
                                   size_t incomingPublishCount );

This function must be called on an MQTTContext_t after MQTT_Init and before any other function.

Parameters

[in]	pContext	The context to initialize.
[in]	pOutgoingPublishRecords	Pointer to memory which will be used to store state of outgoing publishes.
[in]	outgoingPublishCount	Maximum number of records which can be kept in the memory pointed to by pOutgoingPublishRecords.
[in]	pIncomingPublishRecords	Pointer to memory which will be used to store state of incoming publishes.
[in]	incomingPublishCount	Maximum number of records which can be kept in the memory pointed to by pIncomingPublishRecords.

Returns

MQTTBadParameter if invalid parameters are passed; MQTTSuccess otherwise.

Example

// Function for obtaining a timestamp.
uint32_t getTimeStampMs();
// Callback function for receiving packets.
void eventCallback(
     MQTTContext_t * pContext,
     MQTTPacketInfo_t * pPacketInfo,
     MQTTDeserializedInfo_t * pDeserializedInfo
);
// Network send.
int32_t networkSend( NetworkContext_t * pContext, const void * pBuffer, size_t bytes );
// Network receive.
int32_t networkRecv( NetworkContext_t * pContext, void * pBuffer, size_t bytes );
 
MQTTContext_t mqttContext;
TransportInterface_t transport;
MQTTFixedBuffer_t fixedBuffer;
uint8_t buffer[ 1024 ];
const size_t outgoingPublishCount = 30;
MQTTPubAckInfo_t outgoingPublishes[ outgoingPublishCount ];
 
// Clear context.
memset( ( void * ) &mqttContext, 0x00, sizeof( MQTTContext_t ) );
 
// Set transport interface members.
transport.pNetworkContext = &someTransportContext;
transport.send = networkSend;
transport.recv = networkRecv;
 
// Set buffer members.
fixedBuffer.pBuffer = buffer;
fixedBuffer.size = 1024;
 
status = MQTT_Init( &mqttContext, &transport, getTimeStampMs, eventCallback, &fixedBuffer );
 
if( status == MQTTSuccess )
{
     // We do not expect any incoming publishes in this example, therefore the incoming
     // publish pointer is NULL and the count is zero.
     status = MQTT_InitStatefulQoS( &mqttContext, outgoingPublishes, outgoingPublishCount, NULL, 0 );
 
     // Now QoS1 and/or QoS2 publishes can be sent with this context.
}