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.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)socketpair.2 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: src/lib/libc/sys/socketpair.2,v 1.6.2.6 2001/12/14 18:34:01 ru Exp $ 34.\" $DragonFly: src/lib/libc/sys/socketpair.2,v 1.4 2007/07/30 22:11:33 swildner Exp $ 35.\" 36.Dd June 4, 1993 37.Dt SOCKETPAIR 2 38.Os 39.Sh NAME 40.Nm socketpair 41.Nd create a pair of connected sockets 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In sys/types.h 46.In sys/socket.h 47.Ft int 48.Fn socketpair "int d" "int type" "int protocol" "int *sv" 49.Sh DESCRIPTION 50The 51.Fn socketpair 52call creates an unnamed pair of connected sockets in 53the specified domain 54.Fa d , 55of the specified 56.Fa type , 57and using the optionally specified 58.Fa protocol . 59The descriptors used in referencing the new sockets 60are returned in 61.Fa sv Ns [0] 62and 63.Fa sv Ns [1] . 64The two sockets are indistinguishable. 65.Sh RETURN VALUES 66.Rv -std socketpair 67.Sh ERRORS 68The call succeeds unless: 69.Bl -tag -width Er 70.It Bq Er EMFILE 71Too many descriptors are in use by this process. 72.It Bq Er EAFNOSUPPORT 73The specified address family is not supported on this machine. 74.It Bq Er EPROTONOSUPPORT 75The specified protocol is not supported on this machine. 76.It Bq Er EOPNOTSUPP 77The specified protocol does not support creation of socket pairs. 78.It Bq Er EFAULT 79The address 80.Fa sv 81does not specify a valid part of the 82process address space. 83.El 84.Sh SEE ALSO 85.Xr pipe 2 , 86.Xr read 2 , 87.Xr write 2 88.Sh HISTORY 89The 90.Fn socketpair 91function call appeared in 92.Bx 4.2 . 93.Sh BUGS 94This call is currently implemented only for the 95.Ux 96domain. 97