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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35       The following parameters must not be NULL: "h".  For more information
36       see "Non-NULL parameters" in libnbd(3).
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HANDLE STATE

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

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

51       nbd_add_meta_context(3), nbd_block_status(3), nbd_can_meta_context(3),
52       nbd_create(3), nbd_get_meta_context(3), nbd_get_nr_meta_contexts(3),
53       nbd_set_opt_mode(3), libnbd(3).
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AUTHORS

56       Eric Blake
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58       Richard W.M. Jones
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61       Copyright (C) 2019-2021 Red Hat Inc.
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LICENSE

64       This library is free software; you can redistribute it and/or modify it
65       under the terms of the GNU Lesser General Public License as published
66       by the Free Software Foundation; either version 2 of the License, or
67       (at your option) any later version.
68
69       This library is distributed in the hope that it will be useful, but
70       WITHOUT ANY WARRANTY; without even the implied warranty of
71       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
72       Lesser General Public License for more details.
73
74       You should have received a copy of the GNU Lesser General Public
75       License along with this library; if not, write to the Free Software
76       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
77       02110-1301 USA
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81libnbd-1.14.2                     2023-01-03        nbd_clear_meta_contexts(3)
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