socketpair

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 file 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, errno is set
       appropriately, and sv is left unchanged

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

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 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
       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
       On Linux, the only supported domains for this call are AF_UNIX (or
       synonymously, AF_LOCAL) and AF_TIPC (since Linux 4.12).

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

COLOPHON
       This page is part of release 5.03 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.



Linux                             2019-03-06                     SOCKETPAIR(2)