Single-host communication
In this section, we are going to talk about single-host IPC. Multiple-host IPC will be the subject of our discussion in the next chapter. There are four main techniques that can be used by processes to communicate when they reside on the same machine:
- POSIX signals
- POSIX pipes
- POSIX message queues
- Unix domain sockets
POSIX signals, unlike the other preceding techniques, don't create a communication channel between the processes, but can be used as a way to notify a process about an event. In certain scenarios, such signals can be used by processes to notify each other about specific events in the system.
Before jumping to the first IPC technique, POSIX signals, let's discuss file descriptors. Other than POSIX signals, no matter which IPC technique you use, you will be dealing with file descriptors of some sort. Therefore, we'll now dedicate a separate section to them and discuss them further.
