Question

I am noticing that device is not part of the 3.0 api … what do I use instead?

zmq::device (ZMQ_QUEUE, clients, workers);

I found that the devices have been moved to here: https://github.com/zeromq/libzfl

Answer 1

AFAIK, currently there no devices available for 3.x but according to the readme

Less is More

Pre-built devices and zmq_device() removed. Should be made available
as a separate project(s).

Exactly one year ago, pieterh wrote the following on the site about the reasons for removing the devices:

It’s mostly about being able to improve the device layers independently from the libzmq core. It’s been hard to improve these device layers as part of libzmq core, mainly because the core API is considered sacred in ways that other stuff isn’t. I.e. one does not touch a core API except between major versions. So, one does not touch devices if they are part of the core, except between major versions.