socketpair(2)                 System Calls Manual                socketpair(2)

NAME
       socketpair - create a pair of connected sockets

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #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
       to indicate the error, 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
       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.

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

STANDARDS
       POSIX.1-2008.

HISTORY
       POSIX.1-2001, 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).

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

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

Linux man-pages 6.7               2023-10-31                     socketpair(2)