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nbd_aio_disconnect - Man Page

disconnect from the NBD server


 #include <libnbd.h>

 int nbd_aio_disconnect (
       struct nbd_handle *h, uint32_t flags


Issue the disconnect command to the NBD server.  This is not a normal command because NBD servers are not obliged to send a reply.  Instead you should wait for nbd_aio_is_closed(3) to become true on the connection.  Once this command is issued, you cannot issue any further commands.

Although libnbd does not prevent you from issuing this command while still waiting on the replies to previous commands, the NBD protocol recommends that you wait until there are no other commands in flight (see nbd_aio_in_flight(3)), to give the server a better chance at a clean shutdown.

The flags parameter must be 0 for now (it exists for future NBD protocol extensions).  There is no direct synchronous counterpart; however, nbd_shutdown(3) will call this function if appropriate.

Return Value

If the call is successful the function returns 0.


On error -1 is returned.

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

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


This function first appeared in libnbd 1.0.

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


See Also

nbd_aio_in_flight(3), nbd_aio_is_closed(3), nbd_create(3), nbd_shutdown(3), libnbd(3).


Eric Blake

Richard W.M. Jones


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

Referenced By

libnbd(3), NBD(3), nbd_aio_in_flight(3), nbd_shutdown(3).

2024-06-25 libnbd-1.21.1