socketpair(2) — Linux manual page


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

       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, 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.1-2008 TC2.

ERRORS         top

              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.

              The specified protocol does not support creation of socket

              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 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         top

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

COLOPHON         top

       This page is part of release 5.09 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

Linux                            2020-06-09                    SOCKETPAIR(2)

Pages that refer to this page: pipe2(2)pipe(2)socket(2)socketcall(2)syscalls(2)fifo(7)pipe(7)signal-safety(7)socket(7)unix(7)