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.

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.