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.\" $FreeBSD$ 34.\" 35.Dd June 4, 1993 36.Dt SOCKETPAIR 2 37.Os 38.Sh NAME 39.Nm socketpair 40.Nd create a pair of connected sockets 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In sys/types.h 45.In sys/socket.h 46.Ft int 47.Fn socketpair "int d" "int type" "int protocol" "int *sv" 48.Sh DESCRIPTION 49The 50.Fn socketpair 51system call creates an unnamed pair of connected sockets in 52the specified domain 53.Fa d , 54of the specified 55.Fa type , 56and using the optionally specified 57.Fa protocol . 58The descriptors used in referencing the new sockets 59are returned in 60.Fa sv Ns [0] 61and 62.Fa sv Ns [1] . 63The two sockets are indistinguishable. 64.Sh RETURN VALUES 65.Rv -std socketpair 66.Sh ERRORS 67The call succeeds unless: 68.Bl -tag -width Er 69.It Bq Er EMFILE 70Too many descriptors are in use by this process. 71.It Bq Er EAFNOSUPPORT 72The specified address family is not supported on this machine. 73.It Bq Er EPROTONOSUPPORT 74The specified protocol is not supported on this machine. 75.It Bq Er EOPNOTSUPP 76The specified protocol does not support creation of socket pairs. 77.It Bq Er EFAULT 78The address 79.Fa sv 80does not specify a valid part of the 81process address space. 82.El 83.Sh SEE ALSO 84.Xr pipe 2 , 85.Xr read 2 , 86.Xr write 2 87.Sh BUGS 88This call is currently implemented only for the 89.Ux 90domain. 91.Sh HISTORY 92The 93.Fn socketpair 94system call appeared in 95.Bx 4.2 . 96