568
edits
MQTT C example: Difference between revisions
no edit summary
Crodriguez (talk | contribs) (Created page with "=What is MQTT?= MQTT (Message Queuing Telemetry Transport) is a lightweight, publish-subscribe network protocol that transports messages between devices. It is designed for connections with remote locations where a small code footprint is required or network bandwidth is limited. It is widely used in Internet of Things (IoT) applications. =How to use MQTT in C?= Using MQTT in C typically involves using an MQTT client library. One popular library for MQTT in C is the [h...") |
Crodriguez (talk | contribs) No edit summary |
||
| Line 6: | Line 6: | ||
Using MQTT in C typically involves using an MQTT client library. One popular library for MQTT in C is the [https://eclipse.dev/paho/ Paho MQTT library] by the Eclipse Foundation. | Using MQTT in C typically involves using an MQTT client library. One popular library for MQTT in C is the [https://eclipse.dev/paho/ Paho MQTT library] by the Eclipse Foundation. | ||
Paho API can be found [https://eclipse.github.io/paho.mqtt.c/MQTTClient/html/index.html here]. | Paho API can be found [https://eclipse.github.io/paho.mqtt.c/MQTTClient/html/index.html here]. | ||
Paho library can be installed with the following steps: | |||
<pre> | |||
git clone https://github.com/eclipse/paho.mqtt.c.git | |||
cd paho.mqtt.c | |||
mkdir build | |||
cd build | |||
cmake .. | |||
make | |||
sudo make install | |||
</pre> | |||
==Creating Publisher== | |||
Paho provides an example publisher application [https://eclipse.github.io/paho.mqtt.c/MQTTClient/html/pubasync.html here]. | |||
In order to test this app, follow these steps: | |||
* Copy the content of the code to a '''pub_async.c''' file | |||
* Compile the file: | |||
<pre> | |||
gcc -o pub_async pub_async.c -lpaho-mqtt3c | |||
</pre> | |||
* Run the app: | |||
<pre> | |||
./pub_async | |||
</pre> | |||
* You will see something like this: | |||
<pre> | |||
Waiting for publication of Hello World! | |||
on topic MQTT Examples for client with ClientID: ExampleClientPub | |||
Message with token value 1 delivery confirmed | |||
</pre> | |||
==Creating Subscriber== | |||
Paho provides an example subscriber application [https://eclipse.github.io/paho.mqtt.c/MQTTClient/html/subasync.html here]. | |||
In order to test this app, follow these steps: | |||
* Copy the content of the code to a '''sub_async.c''' file | |||
* Compile the file: | |||
<pre> | |||
gcc -o sub_async sub_async.c -lpaho-mqtt3c | |||
</pre> | |||
* Run the app: | |||
<pre> | |||
./sub_async | |||
</pre> | |||
* You will see something like this: | |||
<pre> | |||
Subscribing to topic MQTT Examples | |||
for client ExampleClientSub using QoS1 | |||
Press Q<Enter> to quit | |||
</pre> | |||
* The app will wait for the publisher app to send a message, if you run the publisher app once you will see the following message: | |||
<pre> | |||
Message arrived | |||
topic: MQTT Examples | |||
message: Hello World! | |||
</pre> | |||
* The app will remain active listening for messages until the user closes it. | |||