freebsd-dev/lib/libc/sys/socketpair.2

.\" Copyright (c) 1983, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
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.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" SUCH DAMAGE.
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.\"     @(#)socketpair.2	8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd May 4, 2015
.Dt SOCKETPAIR 2
.Os
.Sh NAME
.Nm socketpair
.Nd create a pair of connected sockets
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/types.h
.In sys/socket.h
.Ft int
.Fn socketpair "int domain" "int type" "int protocol" "int *sv"
.Sh DESCRIPTION
The
.Fn socketpair
system call creates an unnamed pair of connected sockets in
the specified communications
.Fa domain ,
of the specified
.Fa type ,
and using the optionally specified
.Fa protocol .
The descriptors used in referencing the new sockets
are returned in
.Fa sv Ns [0]
and
.Fa sv Ns [1] .
The two sockets are indistinguishable.
.Pp
The
.Dv SOCK_CLOEXEC
and
.Dv SOCK_NONBLOCK
flags in the
.Fa type
argument apply to both descriptors.
.Sh RETURN VALUES
.Rv -std socketpair
.Sh ERRORS
The call succeeds unless:
.Bl -tag -width Er
.It Bq Er EMFILE
Too many descriptors are in use by this process.
.It Bq Er EAFNOSUPPORT
The specified address family is not supported on this machine.
.It Bq Er EPROTONOSUPPORT
The specified protocol is not supported on this machine.
.It Bq Er EOPNOTSUPP
The specified protocol does not support creation of socket pairs.
.It Bq Er EFAULT
The address
.Fa sv
does not specify a valid part of the
process address space.
.El
.Sh SEE ALSO
.Xr pipe 2 ,
.Xr read 2 ,
.Xr socket 2 ,
.Xr write 2
.Sh HISTORY
The
.Fn socketpair
system call appeared in
.Bx 4.2 .
.Sh BUGS
This call is currently implemented only for the
.Ux
domain.
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.\" Copyright (c) 1983, 1991, 1993`
			`.\" The Regents of the University of California. All rights reserved.`
			`.\"`
			`.\" Redistribution and use in source and binary forms, with or without`
			`.\" modification, are permitted provided that the following conditions`
			`.\" are met:`
			`.\" 1. Redistributions of source code must retain the above copyright`
			`.\" notice, this list of conditions and the following disclaimer.`
			`.\" 2. Redistributions in binary form must reproduce the above copyright`
			`.\" notice, this list of conditions and the following disclaimer in the`
			`.\" documentation and/or other materials provided with the distribution.`
Renumber copyright clause 4 Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96 2017-02-28 23:42:47 +00:00			`.\" 3. Neither the name of the University nor the names of its contributors`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.\" may be used to endorse or promote products derived from this software`
			`.\" without specific prior written permission.`
			`.\"`
			.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
			`.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE`
			`.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE`
			`.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE`
			`.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL`
			`.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS`
			`.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)`
			`.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT`
			`.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY`
			`.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF`
			`.\" SUCH DAMAGE.`
			`.\"`
			`.\" @(#)socketpair.2 8.1 (Berkeley) 6/4/93`
$Id$ -> $FreeBSD$ 1999-08-28 00:22:10 +00:00			`.\" $FreeBSD$`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.\"`
Partially revert r255486, the first argument to socketpair() is a socket domain, not a file descriptor. Use 'domain' instead of the original 'd' for this argument to match socket(2). PR: 199491 Reported by: sp55aa@qq.com MFC after: 1 week 2015-05-04 14:23:31 +00:00			`.Dd May 4, 2015`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Dt SOCKETPAIR 2`
mdoc(7) police: removed HISTORY info from the .Os call. 2001-07-10 13:41:46 +00:00			`.Os`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh NAME`
			`.Nm socketpair`
			`.Nd create a pair of connected sockets`
Introduce ".Lb" macro to libc manpages. More libraries manpages updates following. 2000-04-21 09:42:15 +00:00			`.Sh LIBRARY`
			`.Lb libc`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh SYNOPSIS`
mdoc(7) police: Use the new .In macro for #include statements. 2001-10-01 16:09:29 +00:00			`.In sys/types.h`
			`.In sys/socket.h`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Ft int`
Partially revert r255486, the first argument to socketpair() is a socket domain, not a file descriptor. Use 'domain' instead of the original 'd' for this argument to match socket(2). PR: 199491 Reported by: sp55aa@qq.com MFC after: 1 week 2015-05-04 14:23:31 +00:00			`.Fn socketpair "int domain" "int type" "int protocol" "int *sv"`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh DESCRIPTION`
			`The`
			`.Fn socketpair`
mdoc(7) police: Tidy up the syscall language. Stop calling system calls "function calls". Use "The .Fn system call" a-la "The .Nm utility". When referring to a non-BSD implementation in the HISTORY section, call syscall a function, to be safe. 2002-12-18 09:22:32 +00:00			`system call creates an unnamed pair of connected sockets in`
Partially revert r255486, the first argument to socketpair() is a socket domain, not a file descriptor. Use 'domain' instead of the original 'd' for this argument to match socket(2). PR: 199491 Reported by: sp55aa@qq.com MFC after: 1 week 2015-05-04 14:23:31 +00:00			`the specified communications`
			`.Fa domain ,`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`of the specified`
			`.Fa type ,`
			`and using the optionally specified`
			`.Fa protocol .`
			`The descriptors used in referencing the new sockets`
			`are returned in`
			`.Fa sv Ns [0]`
			`and`
			`.Fa sv Ns [1] .`
			`The two sockets are indistinguishable.`
Implement SOCK_CLOEXEC, SOCK_NONBLOCK and MSG_CMSG_CLOEXEC. This change allows creating file descriptors with close-on-exec set in some situations. SOCK_CLOEXEC and SOCK_NONBLOCK can be OR'ed in socket() and socketpair()'s type parameter, and MSG_CMSG_CLOEXEC to recvmsg() makes file descriptors (SCM_RIGHTS) atomically close-on-exec. The numerical values for SOCK_CLOEXEC and SOCK_NONBLOCK are as in NetBSD. MSG_CMSG_CLOEXEC is the first free bit for MSG_. The SOCK_ flags are not passed to MAC because this may cause incorrect failures and can be done later via fcntl() anyway. On the other hand, audit is expected to cope with the new flags. For MSG_CMSG_CLOEXEC, unp_externalize() is extended to take a flags argument. Reviewed by: kib 2013-03-19 20:58:17 +00:00			`.Pp`
			`The`
			`.Dv SOCK_CLOEXEC`
			`and`
			`.Dv SOCK_NONBLOCK`
			`flags in the`
			`.Fa type`
			`argument apply to both descriptors.`
Rename the DIAGNOSTICS sections in several man pages to RETURN VALUES like they should be. 1997-01-12 00:09:02 +00:00			`.Sh RETURN VALUES`
Use the ``.Rv -std'' mdoc(7) macro in appropriate cases. Reviewed by: ru 2001-08-09 13:32:13 +00:00			`.Rv -std socketpair`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh ERRORS`
			`The call succeeds unless:`
Use `Er' variable to define first column width in ERRORS section. It was initially suggested by mdoc(7) style, but was broken over the years 2000-05-04 13:09:25 +00:00			`.Bl -tag -width Er`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.It Bq Er EMFILE`
			`Too many descriptors are in use by this process.`
			`.It Bq Er EAFNOSUPPORT`
			`The specified address family is not supported on this machine.`
			`.It Bq Er EPROTONOSUPPORT`
			`The specified protocol is not supported on this machine.`
mdoc(7) police: Er macro usage cleanup. 2000-11-22 16:02:00 +00:00			`.It Bq Er EOPNOTSUPP`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`The specified protocol does not support creation of socket pairs.`
			`.It Bq Er EFAULT`
			`The address`
			`.Fa sv`
			`does not specify a valid part of the`
			`process address space.`
Prepare for mdoc(7)NG. 2000-12-29 14:08:20 +00:00			`.El`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh SEE ALSO`
Sort cross references. 1997-01-20 23:23:22 +00:00			`.Xr pipe 2 ,`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Xr read 2 ,`
Implement SOCK_CLOEXEC, SOCK_NONBLOCK and MSG_CMSG_CLOEXEC. This change allows creating file descriptors with close-on-exec set in some situations. SOCK_CLOEXEC and SOCK_NONBLOCK can be OR'ed in socket() and socketpair()'s type parameter, and MSG_CMSG_CLOEXEC to recvmsg() makes file descriptors (SCM_RIGHTS) atomically close-on-exec. The numerical values for SOCK_CLOEXEC and SOCK_NONBLOCK are as in NetBSD. MSG_CMSG_CLOEXEC is the first free bit for MSG_. The SOCK_ flags are not passed to MAC because this may cause incorrect failures and can be done later via fcntl() anyway. On the other hand, audit is expected to cope with the new flags. For MSG_CMSG_CLOEXEC, unp_externalize() is extended to take a flags argument. Reviewed by: kib 2013-03-19 20:58:17 +00:00			`.Xr socket 2 ,`
Sort cross references. 1997-01-20 23:23:22 +00:00			`.Xr write 2`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh HISTORY`
			`The`
Correctly use .Fn instead of .Nm to reference function names in a bunch of man pages. Use the correct .Bx (BSD UNIX) or .At (AT&T UNIX) macros instead of explicitly specifying the version in the text in a bunch of man pages. 1996-08-22 23:31:07 +00:00			`.Fn socketpair`
mdoc(7) police: Tidy up the syscall language. Stop calling system calls "function calls". Use "The .Fn system call" a-la "The .Nm utility". When referring to a non-BSD implementation in the HISTORY section, call syscall a function, to be safe. 2002-12-18 09:22:32 +00:00			`system call appeared in`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Bx 4.2 .`
Sort sections. 2005-01-20 09:17:07 +00:00			`.Sh BUGS`
			`This call is currently implemented only for the`
			`.Ux`
			`domain.`