---
name: "nbd_clear_meta_contexts"
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_clear_meta_contexts"
---

# nbd\_clear\_meta\_contexts(3)

reset the list of requested meta contexts

## NAME

nbd\_clear\_meta\_contexts - reset the list of requested meta contexts

## SYNOPSIS

```
 #include <libnbd.h>
 int nbd_clear_meta_contexts (
       struct nbd_handle *h
     );
```

## DESCRIPTION

During connection libnbd can negotiate zero or more metadata contexts with the server.  Metadata contexts are features (such as `"base:allocation"`) which describe information returned by the [**nbd\_block\_status\_64**(3)](/nbd_block_status_64/3.md) command (for `"base:allocation"` this is whether blocks of data are allocated, zero or sparse).

This command resets the list of meta contexts to request back to an empty list, for re-population by further use of [**nbd\_add\_meta\_context**(3)](/nbd_add_meta_context/3.md).  It is primarily useful when option negotiation mode is selected (see [**nbd\_set\_opt\_mode**(3)](/nbd_set_opt_mode/3.md)), for altering the list of attempted contexts between subsequent export queries.

## 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\_clear\_meta\_contexts can be called when the handle is in the following states:

```
 ┌─────────────────────────────────────┬─────────────────────────┐
 │ Handle created, before connecting   │ ✅ allowed              │
 │ 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 1.6.

If you need to test if this function is available at compile time check if the following macro is defined:

```
 #define LIBNBD_HAVE_NBD_CLEAR_META_CONTEXTS 1
```

## SEE ALSO

[**nbd\_add\_meta\_context**(3)](/nbd_add_meta_context/3.md), [**nbd\_block\_status\_64**(3)](/nbd_block_status_64/3.md), [**nbd\_can\_meta\_context**(3)](/nbd_can_meta_context/3.md), [**nbd\_create**(3)](/nbd_create/3.md), [**nbd\_get\_meta\_context**(3)](/nbd_get_meta_context/3.md), [**nbd\_get\_nr\_meta\_contexts**(3)](/nbd_get_nr_meta_contexts/3.md), [**nbd\_set\_opt\_mode**(3)](/nbd_set_opt_mode/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