NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

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

NAME         top

       socketpair - create a pair of connected sockets

SYNOPSIS         top

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

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

DESCRIPTION         top

       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 file descriptors used in referencing the new sockets are returned
       in sv[0] and sv[1].  The two sockets are indistinguishable.

RETURN VALUE         top

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

       On Linux (and other systems), socketpair() does not modify sv on
       failure.  A requirement standardizing this behavior was added in
       POSIX.1-2016.

ERRORS         top

       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 The per-process limit on the number of open file descriptors
              has been reached.

       ENFILE The system-wide 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         top

       POSIX.1-2001, POSIX.1-2008, 4.4BSD.  socketpair() first 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         top

       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 in the type argument, as described in socket(2).

       POSIX.1 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         top

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

COLOPHON         top

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Linux                            2016-03-15                    SOCKETPAIR(2)