Unix ___domain socket

A Unix ___domain(UDS) or IPC socket (inter-process communication socket) is a virtual socket, similar to an internet socket that is used in POSIX operating systems for inter-process communication. The correct standard POSIX term is POSIX Local IPC Sockets.

These connections appear as byte streams, much like network connections, but all data remains within the local computer. UNIX ___domain sockets use the file system as their address name space, i.e. they are viewed by processes as files in a file system. This allows two distinct processes to reference and open the same socket in order to communicate. However, the actual communication (the data exchange) does not use the file system, but buffers in kernel memory.

In addition to sending data, processes can send file descriptors across a Unix ___domain socket connection using the sendmsg() and recvmsg() system calls.

External links

• socketpair: create a pair of connected sockets – System Interfaces Reference, The Single UNIX Specification, Version 5 from The Open Group
• sendmsg: send a message on a socket – System Interfaces Reference, The Single UNIX Specification, Version 5 from The Open Group
• recvmsg: receive a message from a socket – System Interfaces Reference, The Single UNIX Specification, Version 5 from The Open Group
• cmsg: socket ancillary data, including sending/receiving file descriptors – System Interfaces Reference, The Single UNIX Specification, Version 5 from The Open Group
• ucspi-unix, UNIX-___domain socket client-server command-line tools
• unix ___domain sockets
• Unix sockets vs Internet sockets