1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 4. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)socketpair.2 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD$ 30.\" 31.Dd June 4, 1993 32.Dt SOCKETPAIR 2 33.Os 34.Sh NAME 35.Nm socketpair 36.Nd create a pair of connected sockets 37.Sh LIBRARY 38.Lb libc 39.Sh SYNOPSIS 40.In sys/types.h 41.In sys/socket.h 42.Ft int 43.Fn socketpair "int d" "int type" "int protocol" "int *sv" 44.Sh DESCRIPTION 45The 46.Fn socketpair 47system call creates an unnamed pair of connected sockets in 48the specified domain 49.Fa d , 50of the specified 51.Fa type , 52and using the optionally specified 53.Fa protocol . 54The descriptors used in referencing the new sockets 55are returned in 56.Fa sv Ns [0] 57and 58.Fa sv Ns [1] . 59The two sockets are indistinguishable. 60.Sh RETURN VALUES 61.Rv -std socketpair 62.Sh ERRORS 63The call succeeds unless: 64.Bl -tag -width Er 65.It Bq Er EMFILE 66Too many descriptors are in use by this process. 67.It Bq Er EAFNOSUPPORT 68The specified address family is not supported on this machine. 69.It Bq Er EPROTONOSUPPORT 70The specified protocol is not supported on this machine. 71.It Bq Er EOPNOTSUPP 72The specified protocol does not support creation of socket pairs. 73.It Bq Er EFAULT 74The address 75.Fa sv 76does not specify a valid part of the 77process address space. 78.El 79.Sh SEE ALSO 80.Xr pipe 2 , 81.Xr read 2 , 82.Xr write 2 83.Sh HISTORY 84The 85.Fn socketpair 86system call appeared in 87.Bx 4.2 . 88.Sh BUGS 89This call is currently implemented only for the 90.Ux 91domain. 92