This samples uses the Mosquitto (MQTT) library to send a message to an Azure IoT Hub.

1. Follow the general prerequisites

2. Install Visual Studio

   NOTE Enable the Desktop development with C++ workload

3. Install CMake

   NOTE Enable the Add CMake to the system PATH for all users option

4. Install the x64 version of Mosquitto

1. Follow the general prerequisites

2. Install the build tools:

   sudo apt install cmake g++

3. Install Mosquitto client library:

   sudo apt install libmosquitto-dev

1. Change to the mosquitto directory in the cloned repository

2. Edit the config.h file and expand the required connection information:

   #define IOTHUBNAME      "{iothub_name}"
   #define DEVICEID        "{device_id}"
   #define SAS_TOKEN       "{sas_token}"

3. Build the application:

   cmake -Bbuild
   cmake --build build

4. Resulting binaries can be found in the following locations:

   1. Linux: ./build
   2. Windows .\build\Debug

This sample will send a single telemetry message, which can be viewed by monitoring the Hubs events.

1. Start monitoring incoming messages on your Hub:

   az iot hub monitor-events -n {iothub_name}

2. Run the sample executable:

   mosquitto_telemetry

3. Confirm the following output is seen from monitor-events:

   {
       "event": {
           "origin": "pubsub",
           "module": "",
           "interface": "",
           "component": "",
           "payload": "Bonjour MQTT from Mosquitto"
       }
   }

This sample will subscribe to all available MQTT topics, and then display an cloud-to-device message sent from the Hub.

1. Run the sample executable:

   mosquitto_subscribe

2. Send an event from the Hub to the device:

   az iot device c2d-message send --hub-name {iothub_name} --device-id {device_id} --data "hello world"

3. Confirm the following output from the sample:

   Waiting for C2D messages...
   C2D message 'hello world' for topic 'devices/pubsub/messages/devicebound/...`
   Got message for devices/pubsub/messages/# topic

This sample will add a temperature reported property to the device twin, and then read the property back.

1. Run the sample executable:

   mosquitto_device_twin

2. Confirm the following output from the sample, setting and getting a device twin update:

   Setting device twin reported properties....
   Device twin message '' for topic '$iothub/twin/res/204/?$rid=patch_temp&$version=2'
   Setting device twin properties SUCCEEDED.
   
   Getting device twin properties....
   Device twin message '{"desired":{"$version":1},"reported":{"temperature":32,"$version":2}}' for topic '$iothub/twin/res/200/?$rid=123'
   Getting device twin properties SUCCEEDED.