UNIX(7P) UNIX(7P)
NAME
UNIX - local communication domain protocol
SYNOPSIS
DESCRIPTION
The local communication domain protocol, commonly referred to in the industry as the Unix domain protocol, utilizes the path name address
format and the address family. This protocol can be used as an alternative to the Internet protocol family (TCP/IP or UDP/IP) for communi-
cation between processes executing on the same node. It has a significant throughput advantage when compared with local IP loopback, due
primarily to its much lower code execution overhead. Data is looped back at the protocol layer (OSI Level 4), rather than at the driver
layer (OSI Level 2).
Only is supported in the address family.
The HP-UX implementation of the local communication domain protocol does not support the flag in (see recv(2)) and (see send(2)).
Addressing
socket addresses are path names. They are limited to 92 bytes in length, including a terminating null byte. Calls to to an socket utilize
an addressing structure called (see bind(2)). Pointers to this structure should be used in all socket system calls wherever they require a
pointer to a
The include file defines this addressing structure. Within this structure are two notable fields. The first is sun_family, which must be
set to The next is sun_path, which is the null-terminated character string that specifies the path name of the file associated with the
socket (for example,
Only the passive (listening) socket must bind to an address. The active socket connects to that address, but it does not need an address
of its own.
For additional information on using sockets for interprocess communication, refer to the BSD Sockets Interface Programmer's Guide.
Socket Buffer Size
For stream and datagram sockets, the maximum send and receive buffer size is 262142 bytes. The default buffer size is 32768 bytes. The
send and receive buffer sizes can be altered by using the and options of the system call. Refer to getsockopt(2) for details.
AUTHOR
was developed by the University of California, Berkeley.
SEE ALSO
getsockopt(2), socket(2).
UNIX(7P)
