Interprocess communication. A set of programming interfaces that enables a process to communicate data or information to another process. Mechanisms for IPC exist in the various layers of the system, from Mach messaging in the kernel to distributed notifications and Apple events in the application environments. Each IPC mechanism has its own advantages and limitations, so it is not unusual for a program to use multiple IPC mechanisms. Other IPC mechanisms include pipes, named pipes, signals, message queueing, semaphores, shared memory, sockets, the Clipboard, and application services.