socketpair - create a pair of connected sockets
Standard C library (
libc,
-lc)
#include <sys/socket.h>
int socketpair(int domain, int type, int protocol, int sv[2]);
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.
On success, zero is returned. On error, -1 is returned,
errno is set to
indicate the error, and
sv is left unchanged
On Linux (and other systems),
socketpair() does not modify
sv on
failure. A requirement standardizing this behavior was added in POSIX.1-2008
TC2.
- 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.
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 domains for this call are
AF_UNIX (or
synonymously,
AF_LOCAL) and
AF_TIPC (since Linux 4.12).
Since Linux 2.6.27,
socketpair() supports the
SOCK_NONBLOCK and
SOCK_CLOEXEC flags in the
type argument, as described in
socket(2).
pipe(2),
read(2),
socket(2),
write(2),
socket(7),
unix(7)