Inter-process communication

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For other uses, see IPC.

In computing, inter-process communication (IPC) is a set of methods for the exchange of data among multiple threads in one or more processes. Processes may be running on one or more computers connected by a network. IPC methods are divided into methods for message passing, synchronization, shared memory, and remote procedure calls (RPC). The method of IPC used may vary based on the bandwidth and latency of communication between the threads, and the type of data being communicated.

There are several reasons for providing an environment that allows process cooperation:

IPC may also be referred to as inter-thread communication and inter-application communication.

The combination of IPC with the address space concept is the foundation for address space independence/isolation.[1]

Main IPC methods[edit]

Method Short Description Provided by (operating systems or other environments)
File A record stored on disk, or a record synthesized on demand by a file server, which can be accessed by name by a process Most operating systems
Signal A system message sent from one process to another, not usually used to store information but instead give commands. Most operating systems; some systems, such as Win NT subsystem, implement signals in only the C run-time library and provide no support for their use as an IPC method[citation needed]. But other subsystems like the POSIX subsystem provided by default until windows 2000. Then available with interix in XP/2003 then with « windows services for UNIX » (SFU).
Socket A data stream sent over a network interface, either to a different process on the same computer or to another computer Most operating systems
Message queue An anonymous data stream similar to the pipe, but stores and retrieves information in packets. Most operating systems
Pipe A two-way data stream interfaced through standard input and output and is read character by character. All POSIX systems, Windows
Named pipe A pipe implemented through a file on the file system instead of standard input and output. All POSIX systems, Windows
Semaphore A simple structure that synchronizes threads or processes acting on shared resources. All POSIX systems, Windows
Shared memory Multiple processes given access to the same memory, allowing all to change it and read changes made by other processes. All POSIX systems, Windows
Message passing (shared nothing) Similar to the message queue. Used in MPI paradigm, Java RMI, CORBA, DDS, MSMQ, MailSlots, QNX, others
Memory-mapped file A file mapped to RAM and can be modified by changing memory addresses directly instead of outputting to a stream, shares same benefits as a standard file. All POSIX systems, Windows


There are several mechanisms which may be used for IPC, including the following:

The following are platform or programming language specific APIs:

See also[edit]


  1. ^ Jochen Liedtke. On µ-Kernel Construction, Proc. 15th ACM Symposium on Operating System Principles (SOSP), December 1995

External links[edit]