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[thirdparty/man-pages.git] / man2 / socketpair.2

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.\"     @(#)socketpair.2	6.4 (Berkeley) 3/10/91
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.\" Modified 1993-07-24 by Rik Faith <faith@cs.unc.edu>
.\" Modified 1996-10-22 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified 2002-07-22 by Michael Kerrisk <mtk-manpages@gmx.net>
.\" Modified 2004-06-17 by Michael Kerrisk <mtk-manpages@gmx.net>
.\"
.TH SOCKETPAIR 2 2004-06-17 "Linux" "Linux Programmer's Manual"
.SH NAME
socketpair \- create a pair of connected sockets
.SH SYNOPSIS
.B #include <sys/types.h>
.br
.B #include <sys/socket.h>
.sp
.BI "int socketpair(int " d ", int " type ", int " protocol ", int " sv [2]);
.SH DESCRIPTION
The
.BR socketpair ()
call creates an unnamed pair of connected sockets in
the specified domain
.IR d ,
of the specified
.IR type ,
and using the optionally specified
.IR protocol .
The descriptors used in referencing the new sockets are returned in
.IR sv [0]
and
.IR sv [1].
The two sockets are indistinguishable.
.SH "RETURN VALUE"
On success, zero is returned.
On error, \-1 is returned, and
.I errno
is set appropriately.
.SH ERRORS
.TP
.B EAFNOSUPPORT
The specified address family is not supported on this machine.
.TP
.B EFAULT
The address
.I sv
does not specify a valid part of the process address space.
.TP
.B EMFILE
Too many descriptors are in use by this process.
.TP
.B ENFILE
The system limit on the total number of open files has been reached.
.TP
.B EOPNOTSUPP
The specified protocol does not support creation of socket pairs.
.TP
.B EPROTONOSUPPORT
The specified protocol is not supported on this machine.
.SH "CONFORMING TO"
4.4BSD, POSIX.1-2001.
The
.BR socketpair ()
function call appeared in 4.2BSD.
It is generally portable to/from
non-BSD systems supporting clones of the BSD socket layer (including
System V variants).
.SH NOTES
On Linux, the only supported domain for this call is
.BR AF_UNIX
(or synonymously,
.BR AF_LOCAL ).
(Most implementations have the same restriction.)
.SH "SEE ALSO"
.BR pipe (2),
.BR read (2),
.BR socket (2),
.BR write (2),
.BR unix (7)