Using signals for IPC – building a client for the daemon

We have already used signals several times in this book. However, when we did, we always used the kill command to send the signal to the program. This time, we'll write a small client that controls the daemon, my-daemon-v2, from Chapter 6, Spawning Processes and Using Job Control.

This is a typical example of when signals are used for IPC. The daemon has a small "client program" that controls it, so that it can stop it, restart it, reload its configuration file, and so on.

Knowing how to use signals for IPC is a solid start in writing programs that can communicate between them.

Getting ready

For this recipe, you'll need the GCC compiler, the Make tool, and the generic Makefile. You will also need the my-daemon-v2.c file from Chapter 6, Spawning Processes and Using Job Control. There is a copy of that file in this chapter's GitHub directory at https://github.com/PacktPublishing/Linux...