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 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, and errno is set appropriately.

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 Too many descriptors are in use by this process.

       ENFILE The system 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

       4.4BSD, POSIX.1-2001.  The socketpair() function call 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  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  described  in
       socket(2).

       POSIX.1-2001  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 3.54 of the Linux man-pages project.  A description of the project, and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.