#include <sys/socket.h>

     int
     socketpair(int d, int type, int protocol, int *sv);

DESCRIPTION

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

DIAGNOSTICS

     A 0 is returned if the call succeeds, -1 if it fails.

ERRORS

     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.

     [EOPNOSUPPORT]     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.

SEE ALSO

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

BUGS

     This call is currently implemented only for the UNIX domain.

HISTORY

     The socketpair() function call appeared in 4.2BSD.

4.2 Berkeley Distribution        June 4, 1993        4.2 Berkeley Distribution