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 indistinguishable.

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  systems	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 restric-
       tion.)

       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 3.27 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)