nbd_aio_opt_extended_headers(3)

🌸 NAME 🌸

nbd_aio_opt_extended_headers(3) from the LIBNBD manual — bestie, this one is literally “request the server to enable extended headers.” That’s the whole assignment. 💅

✨ SYNOPSIS ✨

#include <libnbd.h>

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

int nbd_aio_opt_extended_headers (
      struct nbd_handle *h,
      nbd_completion_callback completion_callback
    );

🦋 DESCRIPTION 🦋

Okay so here’s the vibe: you’re requesting that the server use extended headers by sending NBD_OPT_EXTENDED_HEADERS. This behaves like the synchronous counterpart nbd_opt_extended_headers(3), except that it does not wait for the server’s response. No cap.

To determine when the request completes, wait for nbd_aio_is_connecting(3) to return false. Or supply the optional completion_callback, which will be invoked as described in “Completion callbacks” in libnbd(3), except that it is automatically retired regardless of return value. Lowkey important: detecting whether the server returns an error (as is done by the return value of the synchronous counterpart) is only possible with a completion callback.

💖 RETURN VALUE 💖

If the call is successful the function returns 0. Slay. ✨

💀 ERRORS 💀

On error -1 is returned. Oof.

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).

👑 HANDLE STATE 👑

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

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

⭐ VERSION ⭐

This function first appeared in libnbd 1.18.

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_OPT_EXTENDED_HEADERS 1

🌈 SEE ALSO 🌈

• nbd_aio_is_connecting(3)
• nbd_create(3)
• nbd_opt_extended_headers(3)
• nbd_set_opt_mode(3)
• libnbd(3)

🫶 AUTHORS 🫶

• Eric Blake
• Richard W.M. Jones

🎀 COPYRIGHT 🎀

Copyright Red Hat

💜 LICENSE 💜

legal bestie 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

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xoxo, your terminal bestie — this page is from libnbd-1.25.8, dated 2026-10-13, and it’s all about nbd_aio_opt_extended_headers(3). 💅✨