nbd_aio_connec...cket_activation(3)

✨ nbd_aio_connect_systemd_socket_activation — the libnbd girlie's guide ✨

okay so this is a page from the LIBNBD manual, bestie — yes, the C library for talking to NBD servers — and today we're learning about nbd_aio_connect_systemd_socket_activation. it's a mouthful, i know, but it's literally iconic, trust. 🎀

nbd_aio_connect_systemd_socket_activation — connect using systemd socket activation

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🌸 SYNOPSIS 🌸

like, here's the whole vibe, character for character:

#include <libnbd.h>

int nbd_aio_connect_systemd_socket_activation (
      struct nbd_handle *h, char **argv
    );

💖 DESCRIPTION 💖

So what does it do? It runs the command as a subprocess and starts connecting to it using systemd socket activation. That's it, that's the whole thing. ✨

And the parameters? They behave exactly as documented in nbd_connect_systemd_socket_activation(3) — same energy, different function (this one's the async version, she's doing her own thing 🦋).

👑 RETURN VALUE 👑

If the call is successful, the function returns 0. Slay. ✅

💀 ERRORS 💀

On error, -1 is returned. Not slay. 😭

For how to get further details of the error, refer to "ERROR HANDLING" in libnbd(3) — it's got you.

Also, heads up: the following parameters must not be NULL: h, argv. For more info, see "Non-NULL parameters" in libnbd(3). don't test fate, bestie. 🙈

🌈 NOTES 🌈

Asynchronous connect call

You can check if the connection attempt is still underway by calling nbd_aio_is_connecting(3). 👀

If nbd_set_opt_mode(3) is enabled, the connection is ready for manual option negotiation once nbd_aio_is_negotiating(3) returns true. Otherwise, the connection attempt will include the NBD handshake, and it's ready for use once nbd_aio_is_ready(3) returns true. main character energy honestly. ⭐

🫶 HANDLE STATE 🫶

so nbd_aio_connect_systemd_socket_activation can be called when the handle is in the following state — vibe check time:

• Handle created, before connecting — ✅ allowed (this is your moment, periodt)
• Connecting — ❌ error
• Connecting & handshaking (opt_mode) — ❌ error
• Connected to the server — ❌ error
• Connection shut down — ❌ error
• Handle dead — ❌ error

like, the only green flag here is "Handle created, before connecting". everything else? error, bestie. no cap. 🚩

🎀 VERSION 🎀

This function first appeared in libnbd 1.2. lil baby icon. 💜

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 🔥

the whole friend group, go say hi:

• nbd_aio_is_connecting(3)
• nbd_aio_is_negotiating(3)
• nbd_aio_is_ready(3)
• nbd_connect_systemd_socket_activation(3)
• nbd_create(3)
• nbd_set_opt_mode(3)
• libnbd(3)

⭐ AUTHORS ⭐

• Eric Blake
• Richard W.M. Jones

🌸 COPYRIGHT 🌸

Copyright Red Hat

💅 LICENSE 💅

okay legal moment, keeping it exact because that's the law and we respect her:

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

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and that's the page, bestie 🧚 this lil slice of docs is from libnbd-1.25.8, dated 2026-10-1 — mwah, bye 💖