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Technical Standard: Networking Services (XNS), Issue 5.2 Draft 2.0
Copyright © 1999 The Open Group
Use of Sockets for Local UNIX Connections
Support for UNIX-Domain sockets is mandatory.
UNIX domain sockets provide process-to-process communication in a
single system.
Headers
Symbolic constant
AF_UNIX
is defined in
<sys/socket.h>
(see
<sys/socket.h>)
to identify the UNIX domain address family.
Header
<sys/un.h>
(see
<sys/un.h>)
contains other definitions used in connection with UNIX domain sockets.
The
sockaddr_storage
structure defined in
<sys/socket.h>
is large enough to accommodate a
sockaddr_un
structure (see
<sys/un.h>)
and is aligned
at an appropriate boundary so that pointers to it can
be cast as pointers to
sockaddr_un
structures and used to access the fields of those structures
without alignment problems. When a
sockaddr_storage
structure is cast as a
sockaddr_un
structure, the
ss_family
field maps onto the
sun_family
field.