nbd\_get\_uri(3) LIBNBD nbd\_get\_uri(3)

# [NAME](#NAME)

nbd\_get\_uri - construct an NBD URI for a connection

# [SYNOPSIS](#SYNOPSIS)

```
 #include <libnbd.h>
 char * nbd_get_uri (
          struct nbd_handle *h
        );
```

# [DESCRIPTION](#DESCRIPTION)

This makes a best effort attempt to construct an NBD URI which could be used to connect back to the same server (using [**nbd\_connect\_uri**(3)](/man/os/libnbd/nbd_connect_uri.3)).

In some cases there is not enough information in the handle to successfully create a URI (eg. if you connected with [**nbd\_connect\_socket**(3)](/man/os/libnbd/nbd_connect_socket.3)). In such cases the call returns "NULL" and further diagnostic information is available via [**nbd\_get\_errno**(3)](/man/os/libnbd/nbd_get_errno.3) and [**nbd\_get\_error**(3)](/man/os/libnbd/nbd_get_error.3) as usual.

Even if a URI is returned it is not guaranteed to work, and it may not be optimal.

[**nbdinfo**(1)](/man/os/libnbd/nbdinfo.1) *--uri* option is a way to access this API from shell scripts.

# [RETURN VALUE](#RETURN_VALUE)

This call returns a string. The caller must free the returned string to avoid a memory leak.

# [ERRORS](#ERRORS)

On error "NULL" is returned.

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

# [HANDLE STATE](#HANDLE_STATE)

nbd\_get\_uri can be called when the handle is in the following states:

```
 ┌─────────────────────────────────────┬─────────────────────────┐
 │ Handle created, before connecting   │ ❌ error                │
 │ Connecting                          │ ✅ allowed              │
 │ Connecting & handshaking (opt_mode) │ ✅ allowed              │
 │ Connected to the server             │ ✅ allowed              │
 │ Connection shut down                │ ✅ allowed              │
 │ Handle dead                         │ ✅ allowed              │
 └─────────────────────────────────────┴─────────────────────────┘
```

# [VERSION](#VERSION)

This function first appeared in libnbd 1.8.

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

```
 #define LIBNBD_HAVE_NBD_GET_URI 1
```

# [SEE ALSO](#SEE_ALSO)

[**nbd\_aio\_connect\_uri**(3)](/man/os/libnbd/nbd_aio_connect_uri.3), [**nbd\_connect\_socket**(3)](/man/os/libnbd/nbd_connect_socket.3), [**nbd\_connect\_uri**(3)](/man/os/libnbd/nbd_connect_uri.3), [**nbd\_create**(3)](/man/os/libnbd/nbd_create.3), [**nbd\_get\_errno**(3)](/man/os/libnbd/nbd_get_errno.3), [**nbd\_get\_error**(3)](/man/os/libnbd/nbd_get_error.3), [**nbd\_is\_uri**(3)](/man/os/libnbd/nbd_is_uri.3), [**nbd\_supports\_uri**(3)](/man/os/libnbd/nbd_supports_uri.3), [**libnbd**(3)](/man/os/libnbd/libnbd.3), [**nbdinfo**(1)](/man/os/libnbd/nbdinfo.1).

# [AUTHORS](#AUTHORS)

Eric Blake

Richard W.M. Jones

# [COPYRIGHT](#COPYRIGHT)

Copyright Red Hat

# [LICENSE](#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

2026-10-11 libnbd-1.25.7

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Document: nbd_get_uri(3) from libnbd 1.25.7-r3 (Chainguard OS)