nbd\_poll2(3) LIBNBD nbd\_poll2(3)

# [NAME](#NAME)

nbd\_poll2 - poll the handle once, with fd

# [SYNOPSIS](#SYNOPSIS)

```
 #include <libnbd.h>
 int nbd_poll2 (
       struct nbd_handle *h, int fd, int timeout
     );
```

# [DESCRIPTION](#DESCRIPTION)

This is the same as [**nbd\_poll**(3)](/man/os/libnbd/nbd_poll.3), but an additional file descriptor parameter is passed. The additional fd is also polled (using "POLLIN"). One use for this is to wait for an [**eventfd**(2)](/man/os/libnbd/eventfd.2).

# [RETURN VALUE](#RETURN_VALUE)

This call returns an integer ≥ 0.

# [ERRORS](#ERRORS)

On error -1 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).

# [VERSION](#VERSION)

This function first appeared in libnbd 1.16.

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

```
 #define LIBNBD_HAVE_NBD_POLL2 1
```

# [SEE ALSO](#SEE_ALSO)

[**nbd\_create**(3)](/man/os/libnbd/nbd_create.3), [**nbd\_poll**(3)](/man/os/libnbd/nbd_poll.3), [**libnbd**(3)](/man/os/libnbd/libnbd.3), [**eventfd**(2)](/man/os/libnbd/eventfd.2).

# [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

2026-10-13 libnbd-1.25.8

---

Document: nbd_poll2(3) from libnbd 1.25.8-r0 (Chainguard OS)