1nbd_clear_meta_contexts(3)          LIBNBD          nbd_clear_meta_contexts(3)
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NAME

6       nbd_clear_meta_contexts - reset the list of requested meta contexts
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SYNOPSIS

9        #include <libnbd.h>
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11        int nbd_clear_meta_contexts (struct nbd_handle *h);
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DESCRIPTION

14       During connection libnbd can negotiate zero or more metadata contexts
15       with the server.  Metadata contexts are features (such as
16       "base:allocation") which describe information returned by the
17       nbd_block_status(3) command (for "base:allocation" this is whether
18       blocks of data are allocated, zero or sparse).
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20       This command resets the list of meta contexts to request back to an
21       empty list, for re-population by further use of
22       nbd_add_meta_context(3).  It is primarily useful when option
23       negotiation mode is selected (see nbd_set_opt_mode(3)), for altering
24       the list of attempted contexts between subsequent export queries.
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RETURN VALUE

27       If the call is successful the function returns 0.
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ERRORS

30       On error "-1" is returned.
31
32       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details
33       of the error.
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HANDLE STATE

36       The handle must be newly created, or negotiating, otherwise this call
37       will return an error.
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VERSION

40       This function first appeared in libnbd 1.6.
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42       If you need to test if this function is available at compile time check
43       if the following macro is defined:
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45        #define LIBNBD_HAVE_NBD_CLEAR_META_CONTEXTS 1
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SEE ALSO

48       nbd_add_meta_context(3), nbd_block_status(3), nbd_can_meta_context(3),
49       nbd_create(3), nbd_get_meta_context(3), nbd_get_nr_meta_contexts(3),
50       nbd_set_opt_mode(3), libnbd(3).
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AUTHORS

53       Eric Blake
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55       Richard W.M. Jones
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58       Copyright (C) 2019-2020 Red Hat Inc.
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LICENSE

61       This library is free software; you can redistribute it and/or modify it
62       under the terms of the GNU Lesser General Public License as published
63       by the Free Software Foundation; either version 2 of the License, or
64       (at your option) any later version.
65
66       This library is distributed in the hope that it will be useful, but
67       WITHOUT ANY WARRANTY; without even the implied warranty of
68       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
69       Lesser General Public License for more details.
70
71       You should have received a copy of the GNU Lesser General Public
72       License along with this library; if not, write to the Free Software
73       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
74       02110-1301 USA
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78libnbd-1.6.2                      2021-03-02        nbd_clear_meta_contexts(3)
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