nbd_aio_peek_command_completed - check if any command has completed

       Eric Blake

       Richard W.M. Jones

       Copyright Red Hat

       Return the unique positive 64 bit cookie of the first non-retired but completed command, 0 if there are
       in-flight commands but none of them are awaiting retirement, or -1 on error including when there are no
       in-flight commands. Any cookie returned by this function must still be passed to
       nbd_aio_command_completed(3) to actually retire the command and learn whether the command was successful.

       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).

       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

libnbd-1.22.2                                      2025-06-16                  nbd_aio_peek_command_completed(3)

       nbd_aio_peek_command_completed - check if any command has completed

       This call returns a 64 bit signed integer ≥ 0.

nbd_aio_command_completed(3), nbd_create(3), libnbd(3).

        #include <libnbd.h>

        int64_t nbd_aio_peek_command_completed (
                  struct nbd_handle *h
                );

       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:

        #define LIBNBD_HAVE_NBD_AIO_PEEK_COMMAND_COMPLETED 1