A complex application-programming model might include a number of processes, each implemented to handle a specific job, which contribute to the end functionality of the application as a whole. Depending on the objective, design, and environment in which such applications are hosted, processes involved might be related (parent-child, siblings) or unrelated. Often, such processes need various resources to communicate, share data, and synchronize their execution to achieve desired results. These are provided by the operating system's kernel as services called interprocess communication (IPC). We have already discussed the usage of signals as an IPC mechanism; in this chapter, we shall begin to explore various other resources available for process communication and data sharing.

In this chapter we will cover the following topics:

• Pipes and FIFOs as messaging resources
• SysV IPC resources
• POSX IPC mechanisms