socketpair(2) System Calls Manual socketpair(2)
NAME
socketpair - create a pair of connected sockets
LIBRARY
Standard C library (libc, -lc)
SYNOPSIS
#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, errno is set to
indicate the error, and sv is left unchanged
On Linux (and other systems), socketpair() does not modify sv on fail-
ure. A requirement standardizing this behavior was added in
POSIX.1-2008 TC2.
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 ad-
dress 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.
VERSIONS
On Linux, the only supported domains for this call are AF_UNIX (or syn-
onymously, AF_LOCAL) and AF_TIPC (since Linux 4.12).
STANDARDS
POSIX.1-2008.
HISTORY
POSIX.1-2001, 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).
Since Linux 2.6.27, socketpair() supports the SOCK_NONBLOCK and
SOCK_CLOEXEC flags in the type argument, as described in socket(2).
SEE ALSO
pipe(2), read(2), socket(2), write(2), socket(7), unix(7)
Linux man-pages 6.9.1 2024-05-02 socketpair(2)
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