1nbd_can_meta_context(3)             LIBNBD             nbd_can_meta_context(3)
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NAME

6       nbd_can_meta_context - does the server support a specific meta context?
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SYNOPSIS

9        #include <libnbd.h>
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11        int nbd_can_meta_context (struct nbd_handle *h,
12                                  const char *metacontext);
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DESCRIPTION

15       Returns true if the server supports the given meta context (see
16       nbd_add_meta_context(3)).  Returns false if the server does not.
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18       The single parameter is the name of the metadata context, for example
19       "LIBNBD_CONTEXT_BASE_ALLOCATION".  <libnbd.h> includes defined
20       constants for well-known namespace contexts beginning with
21       "LIBNBD_CONTEXT_", but you are free to pass in other contexts.
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23       This call does not block, because it returns data that is saved in the
24       handle from the NBD protocol handshake.
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RETURN VALUE

27       This call returns a boolean value.
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ERRORS

30       On error "-1" is returned.
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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", "metacontext".  For
36       more information see "Non-NULL parameters" in libnbd(3).
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HANDLE STATE

39       The handle must be negotiating, or connected with the server, or shut
40       down, otherwise this call will return an error.
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VERSION

43       This function first appeared in libnbd 1.0.
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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_CAN_META_CONTEXT 1
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SEE ALSO

51       nbd_add_meta_context(3), nbd_aio_block_status(3), nbd_block_status(3),
52       nbd_create(3), nbd_opt_info(3), "Flag calls" in libnbd(3), libnbd(3).
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AUTHORS

55       Eric Blake
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57       Richard W.M. Jones
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60       Copyright (C) 2019-2021 Red Hat Inc.
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LICENSE

63       This library is free software; you can redistribute it and/or modify it
64       under the terms of the GNU Lesser General Public License as published
65       by the Free Software Foundation; either version 2 of the License, or
66       (at your option) any later version.
67
68       This library is distributed in the hope that it will be useful, but
69       WITHOUT ANY WARRANTY; without even the implied warranty of
70       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
71       Lesser General Public License for more details.
72
73       You should have received a copy of the GNU Lesser General Public
74       License along with this library; if not, write to the Free Software
75       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
76       02110-1301 USA
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80libnbd-1.14.2                     2023-01-03           nbd_can_meta_context(3)
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