INTERPROCESS
COMMUNICATION OVERVIEW
This chapter presents a brief overview of the facilities that processes and threads
can use to communicate with one another and to synchronize their actions. The
following chapters provide more details about these facilities.43.1 A Taxonomy of IPC Facilities
Figure 43-1 summarizes the rich variety of UNIX communication and synchroniza-
tion facilities, dividing them into three broad functional categories:z Communication: These facilities are concerned with exchanging data between
processes.
z Synchronization: These facilities are concerned with synchronizing the actions
of processes or threads.
z Signals: Although signals are intended primarily for other purposes, they can
be used as a synchronization technique in certain circumstances. More rarely,
signals can be used as a communication technique: the signal number itself is a
form of information, and realtime signals can be accompanied by associated
data (an integer or a pointer). Signals are described in detail in Chapters 20 to 22.