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SOCKETPAIR(2) FreeBSD System Calls Manual SOCKETPAIR(2)
NAME
socketpair - create a pair of connected sockets
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>
int
socketpair(int domain, int type, int protocol, int *sv);
DESCRIPTION
The socketpair() system call creates an unnamed pair of connected sockets
in the specified communications domain, of the specified type, and using
the optionally specified protocol. The descriptors used in referencing
the new sockets are returned in sv[0] and sv[1]. The two sockets are
indistinguishable.
The SOCK_CLOEXEC and SOCK_NONBLOCK flags in the type argument apply to
both descriptors.
RETURN VALUES
The socketpair() function returns the value 0 if successful; otherwise
the value -1 is returned and the global variable errno is set to indicate
the error.
ERRORS
The call succeeds unless:
[EMFILE] Too many descriptors are in use by this process.
[EAFNOSUPPORT] The specified address family is not supported on this
machine.
[EPROTONOSUPPORT] The specified protocol is not supported on this
machine.
[EOPNOTSUPP] The specified protocol does not support creation of
socket pairs.
[EFAULT] The address sv does not specify a valid part of the
process address space.
SEE ALSO
pipe(2), read(2), socket(2), write(2)
STANDARDS
The socketpair() system call conforms to IEEE Std 1003.1-2001 ("POSIX.1")
and IEEE Std 1003.1-2008 ("POSIX.1").
HISTORY
The socketpair() system call appeared in 4.2BSD.
BUGS
This call is currently implemented only for the UNIX domain.