PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.

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, which shall include 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.   Pointers  to  this  type
       shall be cast by applications to struct sockaddr * for use with socket functions.

       The <sys/un.h> header shall define the sa_family_t type 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} bytes (256).

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       <sys_socket.h>

       The System Interfaces volume of POSIX.1‐2008, bind(), socket(), socketpair()

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers,  Inc
       and  The  Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
       during  the  conversion  of  the  source  files  to  man  page  format.  To  report  such   errors,   see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2013                                      sys_un.h(7POSIX)