NAME

       nbd_get_nr_meta_contexts - return the current number of requested meta contexts

SYNOPSIS

        #include <libnbd.h>

        ssize_t nbd_get_nr_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(3) command (for "base:allocation" this is whether blocks
       of data are allocated, zero or sparse).

       This command returns how many meta contexts have been added to the list to request from
       the server via nbd_add_meta_context(3).  The server is not obligated to honor all of the
       requests; to see what it actually supports, see nbd_can_meta_context(3).

RETURN VALUE

       This call returns an integer size ≥ 0.

ERRORS

       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).

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_GET_NR_META_CONTEXTS 1

SEE ALSO

       nbd_add_meta_context(3), nbd_block_status(3), nbd_can_meta_context(3),
       nbd_clear_meta_contexts(3), nbd_create(3), nbd_get_meta_context(3), libnbd(3).

AUTHORS

       Eric Blake

       Richard W.M. Jones

COPYRIGHT

       Copyright (C) 2019-2021 Red Hat Inc.

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