---
name: "nbd_set_request_extended_headers"
section: "3"
platform: "linux"
package: "libnbd"
version: "1.24.4-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/nbd_set_request_extended_headers"
---

# nbd\_set\_request\_extended\_headers(3)

control use of extended headers

## NAME

nbd\_set\_request\_extended\_headers - control use of extended headers

## SYNOPSIS

```
 #include <libnbd.h>
 int nbd_set_request_extended_headers (
       struct nbd_handle *h, bool request
     );
```

## DESCRIPTION

By default, libnbd tries to negotiate extended headers with the server, as this protocol extension permits the use of 64-bit zero, trim, and block status actions.  However, for integration testing, it can be useful to clear this flag rather than find a way to alter the server to fail the negotiation request.

For backwards compatibility, the setting of this knob is ignored if [**nbd\_set\_request\_structured\_replies**(3)](/nbd_set_request_structured_replies/3.md) is also set to false, since the use of extended headers implies structured replies.

## RETURN VALUE

If the call is successful the function returns `0`.

## ERRORS

On error `-1` is returned.

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

## HANDLE STATE

nbd\_set\_request\_extended\_headers 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

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_SET_REQUEST_EXTENDED_HEADERS 1
```

## SEE ALSO

[**nbd\_block\_status\_64**(3)](/nbd_block_status_64/3.md), [**nbd\_cache**(3)](/nbd_cache/3.md), [**nbd\_create**(3)](/nbd_create/3.md), [**nbd\_get\_extended\_headers\_negotiated**(3)](/nbd_get_extended_headers_negotiated/3.md), [**nbd\_get\_request\_extended\_headers**(3)](/nbd_get_request_extended_headers/3.md), [**nbd\_opt\_extended\_headers**(3)](/nbd_opt_extended_headers/3.md), [**nbd\_set\_handshake\_flags**(3)](/nbd_set_handshake_flags/3.md), [**nbd\_set\_request\_structured\_replies**(3)](/nbd_set_request_structured_replies/3.md), [**nbd\_set\_strict\_mode**(3)](/nbd_set_strict_mode/3.md), [**nbd\_trim**(3)](/nbd_trim/3.md), [**nbd\_zero**(3)](/nbd_zero/3.md), [**libnbd**(3)](/libnbd/3.md).

## AUTHORS

Eric Blake

Richard W.M. Jones

## COPYRIGHT

Copyright Red Hat

## 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