c++ sharing single class object between multiple processes

Question

I have a relatively complex class in c++. It works perfectly when used within one process. However, now I want multiple processes to be able to share one object instance of this class. One process (Master) will access read and write functions of the object, while the other 2 processes (Slave) will only use the read functions. I want to modify the class as little as possible. So far I have considered singletons and shared memory, but neither seems ideal or straightforward. This is a research application that will only ever be used by me on Linux. What is the simplest possible solution?

Thanks so much!

Edit: To be absolutely clear, the asker is interested in sharing an object across multiple processes, not threads.

Answer 1

Inter-process communication is never simple. You may want to use a library for IPC/RPC and expose only the function the slaves use to read data, not the entire class.

I can't give you any good recommendations because I have never found a library that made it simple and I don't have much experience with it.

Answer 2

One idea might be to use socket or a socket library to share the data amongst the processes. A library which seems to be very handy for that might be ØMQ. You can also try to use Boost::Asio which is a bit more complex.

You can find a small example for ØMQ here.