IPC ways

Fasest way: shared memory

If you need fast IPC between two processes on one machine, you should look into whatever form of shared memory the platform offers. A simple protocol based around shared memory and locks or semaphores is by far the fastest technique.

Socket

If you do decide to use sockets, bind the “server” socket to ’localhost’. On most platforms, this will take a shortcut around a couple of layers of network code and be quite a bit faster.