---
name: "nbd_aio_connect_systemd_socket_activation"
section: "3"
platform: "linux"
package: "libnbd"
version: "1.24.4-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/nbd_aio_connect_systemd_socket_activation"
---

# nbd\_aio\_connect\_systemd\_socket\_activation(3)

connect using systemd socket activation

## NAME

nbd\_aio\_connect\_systemd\_socket\_activation - connect using systemd socket activation

## SYNOPSIS

```
 #include <libnbd.h>
 int nbd_aio_connect_systemd_socket_activation (
       struct nbd_handle *h, char **argv
     );
```

## DESCRIPTION

Run the command as a subprocess and begin connecting to it using systemd socket activation.  Parameters behave as documented in [**nbd\_connect\_systemd\_socket\_activation**(3)](/nbd_connect_systemd_socket_activation/3.md).

You can check if the connection attempt is still underway by calling [**nbd\_aio\_is\_connecting**(3)](/nbd_aio_is_connecting/3.md).  If [**nbd\_set\_opt\_mode**(3)](/nbd_set_opt_mode/3.md) is enabled, the connection is ready for manual option negotiation once [**nbd\_aio\_is\_negotiating**(3)](/nbd_aio_is_negotiating/3.md) returns true; otherwise, the connection attempt will include the NBD handshake, and is ready for use once [**nbd\_aio\_is\_ready**(3)](/nbd_aio_is_ready/3.md) returns true.

## RETURN VALUE

If the call is successful the function returns `0`.

## ERRORS

On error `-1` is returned.

Refer to "ERROR HANDLING" in [**libnbd**(3)](/libnbd/3.md) for how to get further details of the error.

The following parameters must not be NULL: `"h"`, `"argv"`. For more information see "Non-NULL parameters" in [**libnbd**(3)](/libnbd/3.md).

## HANDLE STATE

nbd\_aio\_connect\_systemd\_socket\_activation can be called when the handle is in the following state:

```
 ┌─────────────────────────────────────┬─────────────────────────┐
 │ Handle created, before connecting   │ ✅ allowed              │
 │ Connecting                          │ ❌ error                │
 │ Connecting & handshaking (opt_mode) │ ❌ error                │
 │ Connected to the server             │ ❌ error                │
 │ Connection shut down                │ ❌ error                │
 │ Handle dead                         │ ❌ error                │
 └─────────────────────────────────────┴─────────────────────────┘
```

## VERSION

This function first appeared in libnbd 1.2.

If you need to test if this function is available at compile time check if the following macro is defined:

```
 #define LIBNBD_HAVE_NBD_AIO_CONNECT_SYSTEMD_SOCKET_ACTIVATION 1
```

## SEE ALSO

[**nbd\_aio\_is\_connecting**(3)](/nbd_aio_is_connecting/3.md), [**nbd\_aio\_is\_negotiating**(3)](/nbd_aio_is_negotiating/3.md), [**nbd\_aio\_is\_ready**(3)](/nbd_aio_is_ready/3.md), [**nbd\_connect\_systemd\_socket\_activation**(3)](/nbd_connect_systemd_socket_activation/3.md), [**nbd\_create**(3)](/nbd_create/3.md), [**nbd\_set\_opt\_mode**(3)](/nbd_set_opt_mode/3.md), [**libnbd**(3)](/libnbd/3.md).

## AUTHORS

Eric Blake

Richard W.M. Jones

## COPYRIGHT

Copyright Red Hat

## LICENSE

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA