SOCKETPAIR(2) Linux Programmer's Manual SOCKETPAIR(2)
socketpair - create a pair of connected sockets
#include <sys/types.h> /* See NOTES */
int socketpair(int domain, int type, int protocol, int sv);
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
The file descriptors used in referencing the new sockets are returned
in sv and sv. The two sockets are indistinguishable.
On success, zero is returned. On error, -1 is returned, and errno is
On Linux (and other systems), socketpair() does not modify sv on fail-
ure. A requirement standardizing this behavior was added in
The specified address family is not supported on this machine.
EFAULT The address sv does not specify a valid part of the process ad-
EMFILE The per-process limit on the number of open file descriptors has
ENFILE The system-wide limit on the total number of open files has been
The specified protocol does not support creation of socket
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 variants).
On Linux, the only supported domain for this call is AF_UNIX (or syn-
onymously, AF_LOCAL). (Most implementations have the same restric-
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.
pipe(2), read(2), socket(2), write(2), socket(7), unix(7)
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Linux 2017-09-15 SOCKETPAIR(2)