---
name: "nng_socket"
section: "7"
platform: "linux"
package: "libnng-dev"
version: "1.10.1-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/nng_socket/7"
---

# nng\_socket(7)

BSD Socket transport (experimental)

## NAME

nng\_socket - BSD Socket transport (experimental)

## DESCRIPTION

The *socket* transport supports communication between peers across arbitrary BSD sockets, such as those that are created with `nng_socket_pair()`.

This transport only supports listeners, using `nng_listener_create()`.

**Note**\

Attempts to create dialers using this transport will result in `NNG_ENOTSUP`.

The socket file descriptor is passed to the listener using the `NNG_OPT_SOCKET_FD` option (as an integer). Setting this option will cause the listener to create a pipe associated backed by the file descriptor.

The protocol between peers using this transport is compatible with the protocol used for the TCP transport, but this is an implementation detail and subject to change without notice.

**Note**\

This transport is **experimental**, and at present is only supported on POSIX platforms.

### Registration

No special action is necessary to register this transport.

### URI Format

This transport uses the URL `socket://`, without further qualification.

### Socket Address

The socket address will be of family `NNG_AF_UNSPEC`. There are no further socket details available.

### Transport Options

The following transport option is available:

`NNG_OPT_SOCKET_FD`

(int) This is a write-only option, that may be set multiple times on a listener. Each time this is set, the listener will create a pipe backed by the given file descriptor passed as an argument.

Additionally, the following options may be supported on pipes when the platform supports them:

• `NNG_OPT_PEER_GID`

• `NNG_OPT_PEER_PID`

• `NNG_OPT_PEER_UID`

• `NNG_OPT_PEER_ZONEID`

## SEE ALSO

nng\_socket\_pair(3), [nng\_dialer(5)](/nng_dialer/5.md), [nng\_listener(5)](/nng_listener/5.md), [nng\_options(5)](/nng_options/5.md), [nng\_pipe(5)](/nng_pipe/5.md), [nng\_sockaddr(5)](/nng_sockaddr/5.md), [nng(7)](/nng/7.md)