SOCKETPAIR(2) Linux Programmer's Manual SOCKETPAIR(2)NAMEsocketpair - create a pair of connected sockets
SYNOPSIS
#include <sys/types.h> /* See NOTES */
#include <sys/socket.h>
int socketpair(int domain, int type, int protocol, int sv[2]);
DESCRIPTION
The socketpair() call creates an unnamed pair of connected sockets in
the specified domain, of the specified type, and 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[0] and sv[1]. The two sockets are indistinguishable.
RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is
set appropriately.
On Linux (and other systems), socketpair() does not modify sv on fail‐
ure. A requirement standardizing this behavior was added in
POSIX.1-2016.
ERRORS
EAFNOSUPPORT
The specified address family is not supported on this machine.
EFAULT The address sv does not specify a valid part of the process
address space.
EMFILE The per-process limit on the number of open file descriptors has
been reached.
ENFILE The system-wide limit on the total number of open files has been
reached.
EOPNOTSUPP
The specified protocol does not support creation of socket
pairs.
EPROTONOSUPPORT
The specified protocol is not supported on this machine.
CONFORMING TO
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 variants).
NOTES
On Linux, the only supported domain for this call is AF_UNIX (or syn‐
onymously, AF_LOCAL). (Most implementations have the same restric‐
tion.)
Since Linux 2.6.27, socketpair() supports the SOCK_NONBLOCK and
SOCK_CLOEXEC flags in the type argument, as described in socket(2).
POSIX.1 does not require the inclusion of <sys/types.h>, 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.
SEE ALSOpipe(2), read(2), socket(2), write(2), socket(7), unix(7)COLOPHON
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Linux 2017-09-15 SOCKETPAIR(2)
