SOCKETPAIR(2)                                       Linux Programmer's Manual                                      SOCKETPAIR(2)



NAME
       socketpair - create a pair of connected sockets

SYNOPSIS
       #include <sys/types.h>          /* See NOTES */
       #include <sys/socket.h>

       int socketpair(int domain, int type, int protocol, int sv[2]);

DESCRIPTION
       The  socketpair()  call  creates an unnamed pair of connected sockets in the specified domain, of the specified type, and
       using the optionally specified protocol.  For further details of these arguments, see socket(2).

       The descriptors used in referencing the new sockets are returned in sv[0] and sv[1].  The two sockets are  indistinguish-
       able.

RETURN VALUE
       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

ERRORS
       EAFNOSUPPORT
              The specified address family is not supported on this machine.

       EFAULT The address sv does not specify a valid part of the process address space.

       EMFILE Too many descriptors are in use by this process.

       ENFILE The system limit on the total number of open files has been reached.

       EOPNOTSUPP
              The specified protocol does not support creation of socket pairs.

       EPROTONOSUPPORT
              The specified protocol is not supported on this machine.

CONFORMING TO
       4.4BSD,  POSIX.1-2001.  The socketpair() function call appeared in 4.2BSD.  It is generally portable to/from non-BSD sys-
       tems supporting clones of the BSD socket layer (including System V variants).

NOTES
       On Linux, the only supported domain for this call is AF_UNIX (or synonymously, AF_LOCAL).  (Most implementations have the
       same restriction.)

       Since Linux 2.6.27, socketpair() supports the SOCK_NONBLOCK and SOCK_CLOEXEC flags described in socket(2).

       POSIX.1-2001  does  not  require the inclusion of <sys/types.h>, and this header file is not required on Linux.  However,
       some historical (BSD) implementations required this header file, and portable applications are probably wise  to  include
       it.

SEE ALSO
       pipe(2), read(2), socket(2), write(2), socket(7), unix(7)

COLOPHON
       This  page  is  part of release 3.25 of the Linux man-pages project.  A description of the project, and information about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                                                      2008-10-11                                              SOCKETPAIR(2)