nbd_aio_zero(3)

📦
version 1.25.8 · 18 versions
, in centos-stream 10

🦋 nbd_aio_zero(3) — LIBNBD's async zero-sending era ✨

okay so bestie, this is the libnbd page for nbd_aio_zero and it's literally the moment you send a write zeroes command to the NBD server without waiting around like a lost little ghost 👻💅

🎀 NAME 🎀

nbd_aio_zero — send write zeroes command to the NBD server 🫶

✨ SYNOPSIS ✨

        #include <libnbd.h>

        typedef struct {
          int (*callback) (void *user_data, int *error);
          void *user_data;
          void (*free) (void *user_data);
        } nbd_completion_callback;

        int64_t nbd_aio_zero (
                  struct nbd_handle *h, uint64_t count,
                  uint64_t offset,
                  nbd_completion_callback completion_callback,
                  uint32_t flags
                );

🌸 DESCRIPTION 🌸

Issue a write zeroes command to the NBD server. that's the whole vibe, no cap ✨

To check if the command completed, call nbd_aio_command_completed(3). Or supply the optional completion_callback which will be invoked as described in "Completion callbacks" in libnbd(3) — yes bestie, the callback is optional, so you can either poll or let it ping you when it's done 📲💖

Other parameters behave as documented in nbd_zero(3). iykyk 🧚

👑 RETURN VALUE 👑

This call returns the 64 bit cookie of the command. The cookie is ≥ 1. Cookies are unique (per libnbd handle, not globally) — so like, your handle has its own little cookie jar and nobody else can claim those cookies 🍪🔥

💀 ERRORS 💀

On error -1 is returned. rude, but okay 😭

Refer to "ERROR HANDLING" in libnbd(3) for how to get further details of the error.

The following parameters must not be NULL: "h". For more information see "Non-NULL parameters" in libnbd(3). so pls don't pass a NULL handle, that's not the move 🙈

⭐ NOTES ⭐

🧚 Strict call 🧚

By default, libnbd will reject attempts to use this function with parameters that are likely to result in server failure, such as requesting an unknown command flag. The nbd_set_strict_mode(3) function can be used to alter which scenarios should await a server reply rather than failing fast. so if you're out here trying unknown flags, libnbd is gonna look at you like "bestie no" 💅

🦋 HANDLE STATE 🦋

nbd_aio_zero can be called when the handle is in the following state:

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

so literally the only green flag is a connected handle, everything else is giving error energy 💀🌈

🎀 VERSION 🎀

This function first appeared in libnbd 1.0. vintage but still iconic ⭐

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_ZERO 1

🔥 SEE ALSO 🔥

go read those when you're done here, bestie 📚💖

🫶 AUTHORS 🫶

Eric Blake

Richard W.M. Jones

Copyright Red Hat

🧚 LICENSE 🧚

okay legal moment, here's the exact tea:

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

this little page is from libnbd-1.25.8, dated 2026-10-13 — mwah, slay, periodt 💋🎀🦋

📦 where this page comes from