<sys/un.h>(P)						     POSIX Programmer's Manual						     <sys/un.h>(P)

NAME

       sys/un.h - definitions for UNIX domain sockets

SYNOPSIS

       #include <sys/un.h>

DESCRIPTION

       The <sys/un.h> header shall define the sockaddr_un structure that includes at least the following members:

	      sa_family_t  sun_family  Address family.
	      char	   sun_path[]  Socket pathname.

       The  sockaddr_un  structure is used to store addresses for UNIX domain sockets. Values of this type shall be cast by applications to struct
       sockaddr for use with socket functions.

       The sa_family_t type shall be defined as described in <sys/socket.h> .

       The following sections are informative.

APPLICATION USAGE

       The size of sun_path has intentionally been left undefined.  This is because different implementations use different  sizes.  For  example,
       4.3  BSD  uses a size of 108, and 4.4 BSD uses a size of 104. Since most implementations originate from BSD versions, the size is typically
       in the range 92 to 108.

       Applications should not assume a particular length for sun_path or assume that it can hold {_POSIX_PATH_MAX} characters (255).

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       <sys/socket.h> , the System Interfaces volume of IEEE Std 1003.1-2001, bind(), socket(), socketpair()

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and  the  original  IEEE
       and  The  Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003							     <sys/un.h>(P)