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Re: [paho-dev] Publish does not appear in Broker

Hi Mike,

I’m not an expert with the C/C++ lib and the APIs, but it seems you’re trying to use MQTT-SN instead of plain MQTT. At least HiveMQ does currently not support MQTT-SN.

Could this be the source of the problem?


On 19 Jul 2018, at 13:07, Mike Maikaefer wrote:


I'm using the embedded C/C++ variant of the PAHO-project out of a
microcontroller. My Problem: although the data are sent (can be verified with WireShark), a broker these data sent to does not recognise them and does not show the related data. This was testedwith HiveMQ and BevyWise

This is what I'm doing to create and send a message (pseudo-code due to
some microcontroller-specific function calls):

   MQTTSNPacket_connectData data=MQTTSNPacket_connectData_initializer;
   int                      rc=0,payloadlen,len;
   unsigned char            buf[MAX_BUFLEN+1];
   MQTTSN_topicid           topic;
   char                     payload[200+1];
   char                     id[200+1];

--> open a TCP/IP conection to the broker here

data.clientID.cstring=(char*)m_machineID->c_str(); // get identifier
from std::string
   len = MQTTSNSerialize_connect(buf,MAX_BUFLEN,&data);*)topicData->c_str(); // get the topic data;
   strncpy(payload,payData->c_str(),200); // get the data to be sent

// here the fourth parameter has to be "3", when setting it to "0", the
topic does not become part
   // of the data in "buf"


--> send the data in "buf" with the length "len" here - this is successful
--> close the TCP/IP connection to the broker here

Any idea what I'm doing wrong here?

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