Chapter 1, Getting Started, explains what a message queuing system is, discusses the importance of message queuing, and introduces ZeroMQ to the reader. It also introduces the request-reply pattern with the "hello world" example and shows examples of how to handle string in C and version reporting in ZeroMQ.

Chapter 2, Introduction to Sockets, explores how to use ZeroMQ with sockets by providing example code.

Chapter 3, Using Socket Topology, goes beyond Chapter 2, Introduction to Sockets, and discusses the difference between ZeroMQ sockets and TCP sockets and shows how to use the topics covered in the previous chapters for real-world applications.

Chapter 4, Advanced Patterns, is a brief introduction to more advanced topics and discusses how to use patterns in ZeroMQ applications.

Appendix, contains bibliography and external links.

To run the examples in the book the following software will be required:

This book is for developers who are interested in learning and implementing ZeroMQ for their applications. The reader needs to have basic C programming knowledge. Prior ZeroMQ experience is not expected.

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text are shown as follows: "You may use czmq.h which lets C developers to code their ZeroMQ applications easier and shorter."

A block of code is set as follows:

#include <string.h>
#include <stdio.h>
#include "zmq.h"


int main (int argc, char const *argv[]) {
  void* context = zmq_init(1);
  void* request = zmq_socket(context, ZMQ_REQ);
  printf("Connecting to server\n");
  zmq_connect(request, "tcp://localhost:4040");
  
  zmq_close(request);
  zmq_term(context);
  return 0;
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

#include <string.h>
#include <stdio.h>
#include "zmq.h"

int main (int argc, char const *argv[]) {
  void* context = zmq_init(1);
  void* request = zmq_socket(context, ZMQ_REQ);
  printf("Connecting to server\n");
  zmq_connect(request, "tcp://localhost:4040");
  
  zmq_close(request);
  zmq_term(context);
  return 0;
}

Any command-line input or output is written as follows:

gcc -Wall -lzmq -o zero zero.c

When we say zmq_socket(2) we mean zmq_socket function takes two parameters. When we say zmq_ctx_new() we mean zmq_ctx_new function does not take any parameters.

New terms and important words are shown in bold.

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