1nbd_get_protocol(3) LIBNBD nbd_get_protocol(3)
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6 nbd_get_protocol - return the NBD protocol variant
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9 #include <libnbd.h>
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11 const char * nbd_get_protocol (
12 struct nbd_handle *h
13 );
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16 Return the NBD protocol variant in use on the connection. At the
17 moment this returns one of the strings "oldstyle", "newstyle" or
18 "newstyle-fixed". Other strings might be returned in the future. Most
19 modern NBD servers use "newstyle-fixed".
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21 This call does not block, because it returns data that is saved in the
22 handle from the NBD protocol handshake.
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25 This call returns a statically allocated string, valid for the lifetime
26 of the process or until libnbd is unloaded by dlclose(3). You must not
27 try to free the string.
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30 On error "NULL" 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". For more information
36 see "Non-NULL parameters" in libnbd(3).
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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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43 This function first appeared in libnbd 1.2.
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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_GET_PROTOCOL 1
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51 nbd_create(3), nbd_get_block_size(3), nbd_get_handshake_flags(3),
52 nbd_get_structured_replies_negotiated(3), nbd_get_tls_negotiated(3),
53 libnbd(3).
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56 Eric Blake
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58 Richard W.M. Jones
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61 Copyright Red Hat
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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.
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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.
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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-1.16.5 2023-09-26 nbd_get_protocol(3)