Section (2) socketpair
socketpair — create a pair of connected sockets
#include <sys/types.h> /* See NOTES */ #include <sys/socket.h>
creates an unnamed pair of connected sockets in the specified
domain, of the
using the optionally specified
protocol. For further details
of these arguments, see socket(2).
The file descriptors used in referencing the new sockets
are returned in
sv. The two
sockets are indistinguishable.
On success, zero is returned. On error, −1 is
errno is set
is left unchanged
On Linux (and other systems),
socketpair() does not modify
sv on failure. A requirement
standardizing this behavior was added in POSIX.1-2016.
The specified address family is not supported on this machine.
svdoes not specify a valid part of the process address space.
The per-process limit on the number of open file descriptors has been reached.
The system-wide limit on the total number of open files has been reached.
The specified protocol does not support creation of socket pairs.
The specified protocol is not supported on this machine.
POSIX.1-2001, POSIX.1-2008, 4.4BSD.
socketpair() first appeared in 4.2BSD. It
is generally portable to/from non-BSD systems supporting
clones of the BSD socket layer (including System V
On Linux, the only supported domains for this call are
AF_UNIX (or synonymously,
AF_TIPC (since Linux 4.12).
Since Linux 2.6.27,
socketpair() supports the
SOCK_CLOEXEC flags in the
type argument, as described in
POSIX.1 does not require the inclusion of
> and this header file is not required on
Linux. However, some historical (BSD) implementations
required this header file, and portable applications are
probably wise to include it.
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(#)socketpair.2 6.4 (Berkeley) 3/10/91
Modified 1993-07-24 by Rik Faith <faithcs.unc.edu>
Modified 1996-10-22 by Eric S. Raymond <esrthyrsus.com>
Modified 2002-07-22 by Michael Kerrisk <mtk.manpagesgmail.com>
Modified 2004-06-17 by Michael Kerrisk <mtk.manpagesgmail.com>
2008-10-11, mtk: Add description of SOCK_NONBLOCK and SOCK_CLOEXEC