It looks like we are stuck, but there must be some way to solve this. If you remember
from Chapter 1 , Getting Started , we said that ZeroMQ gives us tools to code our
own message-queuing service. We are going to implement a broker to solve this
Extended request-reply pattern
When there is a broker, servers and clients do not interact directly with each other.
They communicate only through a broker.
This is a brief introduction to more advanced topics that we will cover later in
Writing multithreaded applications with
ZeroMQ threads are native threads, which means they are OS threads instead of green
threads. The difference between native threads and green threads is that the latter run
on user space whereas the former run on kernel space. The main disadvantage of green
threads is that the OS has no clue what is going on since these kinds of threads do not
rely on the operating system.