205 lines
4.5 KiB
HTML
205 lines
4.5 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML><HEAD><TITLE>Man page of SOCKETPAIR</TITLE>
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</HEAD><BODY>
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<H1>SOCKETPAIR</H1>
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Section: Linux Programmer's Manual (2)<BR>Updated: 2019-03-06<BR><A HREF="#index">Index</A>
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<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
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<A NAME="lbAB"> </A>
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<H2>NAME</H2>
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socketpair - create a pair of connected sockets
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<B>#include <<A HREF="file:///usr/include/sys/types.h">sys/types.h</A>></B> /* See NOTES */
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<BR>
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<B>#include <<A HREF="file:///usr/include/sys/socket.h">sys/socket.h</A>></B>
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<P>
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<B>int socketpair(int </B><I>domain</I><B>, int </B><I>type</I><B>, int </B><I>protocol</I><B>, int </B><I>sv</I><B>[2]);</B>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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The
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<B>socketpair</B>()
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call creates an unnamed pair of connected sockets in the specified
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<I>domain</I>,
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of the specified
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<I>type</I>,
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and using the optionally specified
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<I>protocol</I>.
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For further details of these arguments, see
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<B><A HREF="/cgi-bin/man/man2html?2+socket">socket</A></B>(2).
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<P>
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The file descriptors used in referencing the new sockets are returned in
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<I>sv</I>[0]
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and
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<I>sv</I>[1].
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The two sockets are indistinguishable.
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<A NAME="lbAE"> </A>
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<H2>RETURN VALUE</H2>
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On success, zero is returned.
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On error, -1 is returned,
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<I>errno</I>
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is set appropriately, and
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<I>sv</I>
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is left unchanged
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<P>
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On Linux (and other systems),
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<B>socketpair</B>()
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does not modify
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<I>sv</I>
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on failure.
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A requirement standardizing this behavior was added in POSIX.1-2016.
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<A NAME="lbAF"> </A>
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<H2>ERRORS</H2>
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<DL COMPACT>
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<DT id="1"><B>EAFNOSUPPORT</B>
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<DD>
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The specified address family is not supported on this machine.
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<DT id="2"><B>EFAULT</B>
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<DD>
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The address
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<I>sv</I>
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does not specify a valid part of the process address space.
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<DT id="3"><B>EMFILE</B>
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<DD>
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The per-process limit on the number of open file descriptors has been reached.
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<DT id="4"><B>ENFILE</B>
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<DD>
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The system-wide limit on the total number of open files has been reached.
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<DT id="5"><B>EOPNOTSUPP</B>
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<DD>
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The specified protocol does not support creation of socket pairs.
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<DT id="6"><B>EPROTONOSUPPORT</B>
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<DD>
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The specified protocol is not supported on this machine.
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</DL>
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<A NAME="lbAG"> </A>
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<H2>CONFORMING TO</H2>
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POSIX.1-2001, POSIX.1-2008, 4.4BSD.
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<B>socketpair</B>()
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first appeared in 4.2BSD.
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It is generally portable to/from
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non-BSD systems supporting clones of the BSD socket layer (including
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System V variants).
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<A NAME="lbAH"> </A>
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<H2>NOTES</H2>
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On Linux, the only supported domains for this call are
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<B>AF_UNIX</B>
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(or synonymously,
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<B>AF_LOCAL</B>)
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and
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<B>AF_TIPC</B>
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(since Linux 4.12).
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<P>
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Since Linux 2.6.27,
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<B>socketpair</B>()
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supports the
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<B>SOCK_NONBLOCK</B>
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and
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<B>SOCK_CLOEXEC</B>
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flags in the
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<I>type</I>
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argument, as described in
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<B><A HREF="/cgi-bin/man/man2html?2+socket">socket</A></B>(2).
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<P>
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POSIX.1 does not require the inclusion of
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<I><<A HREF="file:///usr/include/sys/types.h">sys/types.h</A>></I>,
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and this header file is not required on Linux.
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However, some historical (BSD) implementations required this header
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file, and portable applications are probably wise to include it.
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<A NAME="lbAI"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?2+pipe">pipe</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+read">read</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+socket">socket</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+write">write</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?7+socket">socket</A></B>(7),
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<B><A HREF="/cgi-bin/man/man2html?7+unix">unix</A></B>(7)
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<A NAME="lbAJ"> </A>
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<H2>COLOPHON</H2>
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This page is part of release 5.05 of the Linux
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<I>man-pages</I>
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project.
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A description of the project,
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information about reporting bugs,
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and the latest version of this page,
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can be found at
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<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
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<P>
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<HR>
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<A NAME="index"> </A><H2>Index</H2>
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<DL>
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<DT id="7"><A HREF="#lbAB">NAME</A><DD>
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<DT id="8"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="9"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="10"><A HREF="#lbAE">RETURN VALUE</A><DD>
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<DT id="11"><A HREF="#lbAF">ERRORS</A><DD>
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<DT id="12"><A HREF="#lbAG">CONFORMING TO</A><DD>
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<DT id="13"><A HREF="#lbAH">NOTES</A><DD>
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<DT id="14"><A HREF="#lbAI">SEE ALSO</A><DD>
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<DT id="15"><A HREF="#lbAJ">COLOPHON</A><DD>
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</DL>
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<HR>
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This document was created by
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<A HREF="/cgi-bin/man/man2html">man2html</A>,
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using the manual pages.<BR>
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Time: 00:05:34 GMT, March 31, 2021
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