pubsubclient VS pubsubclient

If you're after example code, take a look in https://github.com/knolleary/pubsubclient/tree/master/examples

Here is a fairly basic MQTT example for Arduino-compatible devices.

Have a look at this example.

What do you mean pubsubclient.h doesn't accept URLs as argument? Check out this example. You can change the mqtt_server variable to be whatever the hivemq URL is.

On Arduino, the most used library is pubsubclient

I'm using v 2.8 of Nick O'Leary's pub/sub client (https://github.com/knolleary/pubsubclient). Other libraries are what gets installed from the install of the toolchain. In the case of Arduino this is apt install arduino on Debian and installing the PlatformIO toolchain via the VS Code extension installer.

I am using this MQTT client library for Arduino/ESP, and its API is like this page. The callback function for message reception event is like the following:

I got the built in LED blinking within a couple minutes. (Great Success! :D ) I haven't done as well with MQTT. :-/ I started following a tutorial at https://vimalb.github.io/IoT-ESP8266-Starter/Lesson_04/lesson.html and immediately ran into the header PubSubClient.h not found. I went into Tools -> Manage Libraries, entered "MQTT" in the search field and came up with over 30 libraries! Next I did a search for the missing header error message and that led me to https://github.com/Imroy/pubsubclient. I installed that and it gets me past the missing header, but when I try to create a PubSubClient I get error: no matching function for call to 'PubSubClient::PubSubClient()' which means there is no default constructor for this class. So I'm not sure if I have the wrong library or if it has been modified since the tutorial was written.