socketpair(3N)

NAME
     socketpair - create a pair of connected sockets

SYNOPSIS
     #include <sys/types.h>
     #include <sys/socket.h>

     int socketpair(int d, int type, int protocol, int sv[2]);

DESCRIPTION
     The socketpair library call creates an unnamed pair of connected sockets
     in the specified address family d, 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.

RETURN VALUE
     socketpair returns a -1 on failure, otherwise it returns the number of
     the second file descriptor it creates.

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.

     ENOMEM              There was insufficient user memory for the operation
                         to complete.

     ENOSR               There were insufficient STREAMS resources for the
                         operation to complete.

SEE ALSO
     pipe(2), read(2), write(2)

NOTES
     This call is currently implemented only for the AF_UNIX address family.