nbd_aio_flush(3)

🌸 nbd_aio_flush(3) 🌸

✨ NAME ✨

nbd_aio_flush — send flush command to the NBD server. welcome to the LIBNBD manual, bestie, we're so back 💖

💖 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_flush (
                  struct nbd_handle *h,
                  nbd_completion_callback completion_callback,
                  uint32_t flags
                );

🦋 DESCRIPTION 🦋

okay so this one issues the flush command to the NBD server. iconic behavior, no notes 💅

to check if the command completed, call nbd_aio_command_completed(3) — that's your vibe check. or supply the optional completion_callback, which will be invoked as described in "Completion callbacks" in libnbd(3).

other parameters behave as documented in nbd_flush(3). periodt 🫶

🌈 RETURN VALUE 🌈

this call returns the 64 bit cookie of the command. the cookie is ≥ 1. cookies are unique (per libnbd handle, not globally). iykyk 🍓

💀 ERRORS 💀

on error -1 is returned. tragic, but at least it's documented 😭

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).

📝 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. strict mode said "not today" 💀✨

👑 HANDLE STATE 👑

nbd_aio_flush 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 basically: be connected, bestie. that's the whole mood 👑💅

⭐ VERSION ⭐

this function first appeared in libnbd 1.0.

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_FLUSH 1

🎀 SEE ALSO 🎀

• nbd_aio_command_completed(3)
• nbd_can_flush(3)
• nbd_create(3)
• nbd_flush(3)
• nbd_set_strict_mode(3)
• "Issuing asynchronous commands" in libnbd(3)
• libnbd(3)

🫶 AUTHORS 🫶

• Eric Blake
• Richard W.M. Jones

💅 COPYRIGHT 💅

Copyright Red Hat

📜 LICENSE 📜

the legal bit, unchanged because we do not mess with legal 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

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mwah 💋 that's the whole page, bestie. this one comes from libnbd-1.25.8, dated 2026-10-13, and it's the nbd_aio_flush(3) page. byeee 🫶✨