1nbd_get_protocol(3)                 LIBNBD                 nbd_get_protocol(3)
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NAME

6       nbd_get_protocol - return the NBD protocol variant
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SYNOPSIS

9        #include <libnbd.h>
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11        const char * nbd_get_protocol (struct nbd_handle *h);
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DESCRIPTION

14       Return the NBD protocol variant in use on the connection.  At the
15       moment this returns one of the strings "oldstyle", "newstyle" or
16       "newstyle-fixed".  Other strings might be returned in the future.  Most
17       modern NBD servers use "newstyle-fixed".
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19       This call does not block, because it returns data that is saved in the
20       handle from the NBD protocol handshake.
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RETURN VALUE

23       This call returns a statically allocated string, valid for the lifetime
24       of the process or until libnbd is unloaded by dlclose(3).  You must not
25       try to free the string.
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ERRORS

28       On error "NULL" is returned.
29
30       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details
31       of the error.
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33       The following parameters must not be NULL: "h".  For more information
34       see "Non-NULL parameters" in libnbd(3).
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HANDLE STATE

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

41       This function first appeared in libnbd 1.2.
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43       If you need to test if this function is available at compile time check
44       if the following macro is defined:
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46        #define LIBNBD_HAVE_NBD_GET_PROTOCOL 1
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SEE ALSO

49       nbd_create(3), nbd_get_block_size(3), nbd_get_handshake_flags(3),
50       nbd_get_structured_replies_negotiated(3), nbd_get_tls_negotiated(3),
51       libnbd(3).
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AUTHORS

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

62       This library is free software; you can redistribute it and/or modify it
63       under the terms of the GNU Lesser General Public License as published
64       by the Free Software Foundation; either version 2 of the License, or
65       (at your option) any later version.
66
67       This library is distributed in the hope that it will be useful, but
68       WITHOUT ANY WARRANTY; without even the implied warranty of
69       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
70       Lesser General Public License for more details.
71
72       You should have received a copy of the GNU Lesser General Public
73       License along with this library; if not, write to the Free Software
74       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
75       02110-1301 USA
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79libnbd-1.14.2                     2023-01-03               nbd_get_protocol(3)
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