socketpair — create a pair of connected sockets

       This call is currently implemented only for the Unix domain.

Debian                                          February 10, 2018                                  SOCKETPAIR(2)

       The socketpair() system call creates an unnamed pair of connected sockets in the specified communications
       domain,  of  the  specified  type,  and using the optionally specified protocol.  The descriptors used in
       referencing the new sockets are returned in sv[0] and sv[1].  The two sockets are indistinguishable.

       The SOCK_CLOEXEC and SOCK_NONBLOCK flags in the type argument apply to both descriptors.

       The call succeeds unless:

       [EMFILE]           Too many descriptors are in use by this process.

       [EAFNOSUPPORT]     The specified address family is not supported on this machine.

       [EPROTONOSUPPORT]  The specified protocol is not supported on this machine.

       [EOPNOTSUPP]       The specified protocol does not support creation of socket pairs.

       [EFAULT]           The address sv does not specify a valid part of the process address space.

       The socketpair() system call appeared in 4.2BSD.

       Standard C Library (libc, -lc)

       socketpair — create a pair of connected sockets

       The socketpair() function returns the value 0 if successful; otherwise the value -1 is returned  and  the
       global variable errno is set to indicate the error.

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

       The  socketpair()  system  call  conforms  to  IEEE  Std 1003.1-2001 (“POSIX.1”) and IEEE Std 1003.1-2008
       (“POSIX.1”).

#include<sys/types.h>#include<sys/socket.h>intsocketpair(intdomain, inttype, intprotocol, int*sv);