System V IPC is the label used to refer to three different mechanisms for interprocess communication: message queues, semaphores, and shared memory.
Although these three forms of IPC are quite diverse in function, there are good reasons for discussing them together. One reason is that these mechanisms were developed together, and originally made their way into mainstream Unix by appearing in System V--hence the appellation System V IPC. A more significant reason for discussing the System V IPC mechanisms together is that their programming interfaces share a number of common characteristics, so that many of the same concepts apply to all of these mechanisms.
This chapter provides an overview of the System V IPC mechanisms and details those features that are common to all three mechanisms. The three mechanisms are then discussed individually in the following chapters.
45 Introduction to System V IPC
45.1 API Overview
45.2 IPC Keys
45.3 Associated Data Structure and Object Permissions
45.4 IPC Identifiers and Client-server Applications
45.5 Algorithm Employed by System V IPC get Calls
45.6 The ipcs and ipcrm Commands
45.7 Obtaining a List of All IPC Objects
45.8 IPC Limits