= nng_socket_pair(3)
//
// Copyright 2023 Staysail Systems, Inc. <info@staysail.tech>
//
// This document is supplied under the terms of the MIT License, a
// copy of which should be located in the distribution where this
// file was obtained (LICENSE.txt).  A copy of the license may also be
// found online at https://opensource.org/licenses/MIT.
//

== NAME

nng_socket_pair - create a connected pair of BSD sockets

== SYNOPSIS

[source, c]
----
#include <nng/nng.h>
#include <nng/supplemental/util/platform.h>

int nng_socket_pair(int fds[2]);
----

== DESCRIPTION

The `nng_socket_pair()` function creates a pair of connected BSD sockets.
These sockets, which are returned in the _fds_ array, are suitable for
use with the xref:nng_socket.7.adoc[_socket_] transport.

On POSIX platforms, this is a thin wrapper around the standard `socketpair()` function,
using the `AF_UNIX` family and the `SOCK_STREAM` socket type.

NOTE: At present only POSIX platforms implementing `socketpair()` are supported with this function.

TIP: This function may be useful for creating a shared connection between a parent process and
a child process on UNIX platforms, without requiring the processes use a shared filesystem or TCP connection.

== RETURN VALUES

This function returns 0 on success, and non-zero otherwise.

== ERRORS

[horizontal]
`NNG_ENOMEM`:: Insufficient memory exists.
`NNG_ENOTSUP`:: This platform does not support socket pairs.

== SEE ALSO

[.text-left]
xref:nng_socket.7.adoc[nng_socket(7)],
xref:nng.7.adoc[nng(7)]
