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

# [NAME](#NAME)

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

# [SYNOPSIS](#SYNOPSIS)

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

# [DESCRIPTION](#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)](/man/os/libnbd/nbd_connect_systemd_socket_activation.3).

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

# [RETURN VALUE](#RETURN_VALUE)

If the call is successful the function returns 0.

# [ERRORS](#ERRORS)

On error -1 is returned.

Refer to "ERROR HANDLING" in [**libnbd**(3)](/man/os/libnbd/libnbd.3) 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)](/man/os/libnbd/libnbd.3).

# [HANDLE STATE](#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](#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](#SEE_ALSO)

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

# [AUTHORS](#AUTHORS)

Eric Blake

Richard W.M. Jones

# [COPYRIGHT](#COPYRIGHT)

Copyright Red Hat

# [LICENSE](#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

2026-09-11 libnbd-1.25.7

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Document: nbd_aio_connect_systemd_socket_activation(3) from libnbd 1.25.7-r2 (Chainguard OS)