SOCKETPAIR(2) BSD System Calls Manual SOCKETPAIR(2)
socketpair -- create a pair of connected sockets
socketpair(int d, int type, int protocol, int sv);
The socketpair() call creates an unnamed pair of connected sockets in the
specified domain d, of the specified type, and using the optionally spec-
ified protocol. The descriptors used in referencing the new sockets are
returned in sv and sv. The two sockets are indistinguishable.
Any combination of the following flags may additionally be used in the
SOCK_CLOEXEC Set close-on-exec flag on both the new descriptors.
SOCK_NONBLOCK Set non-blocking I/O mode on both the new sockets.
Upon successful completion, the value 0 is returned; otherwise the
value -1 is returned and the global variable errno is set to indicate the
The call succeeds unless:
[EAFNOSUPPORT] The specified address family is not supported on this
[EPROTONOSUPPORT] The specified protocol is not supported on this
[EOPNOTSUPP] The specified protocol does not support creation of
[EPROTOTYPE] The combination of the specified protocol and type is
[EMFILE] The per-process descriptor table is full.
[ENFILE] The system file table is full.
[ENOBUFS] Insufficient resources were available in the system to
perform the operation.
[EFAULT] The address sv does not specify a valid part of the
process address space.
pipe(2), read(2), socket(2), write(2)
The socketpair() function conforms to IEEE Std 1003.1-2008 (``POSIX.1'').
The socketpair() function call appeared in 4.2BSD.
This call is currently implemented only for the LOCAL domain. Many oper-
ating systems only accept a protocol of PF_UNSPEC, so that should be used
instead of PF_LOCAL for maximal portability.
BSD April 29, 2017 BSD