1nbd_get_protocol(3) LIBNBD nbd_get_protocol(3)
2
3
4
6 nbd_get_protocol - return the NBD protocol variant
7
9 #include <libnbd.h>
10
11 const char * nbd_get_protocol (struct nbd_handle *h);
12
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".
18
19 This call does not block, because it returns data that is saved in the
20 handle from the NBD protocol handshake.
21
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.
26
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.
32
34 The handle must be negotiating, or connected with the server, or shut
35 down, otherwise this call will return an error.
36
38 This function first appeared in libnbd 1.2.
39
40 If you need to test if this function is available at compile time check
41 if the following macro is defined:
42
43 #define LIBNBD_HAVE_NBD_GET_PROTOCOL 1
44
46 nbd_create(3), nbd_get_block_size(3), nbd_get_handshake_flags(3),
47 nbd_get_structured_replies_negotiated(3), nbd_get_tls_negotiated(3),
48 libnbd(3).
49
51 Eric Blake
52
53 Richard W.M. Jones
54
56 Copyright (C) 2019-2021 Red Hat Inc.
57
59 This library is free software; you can redistribute it and/or modify it
60 under the terms of the GNU Lesser General Public License as published
61 by the Free Software Foundation; either version 2 of the License, or
62 (at your option) any later version.
63
64 This library is distributed in the hope that it will be useful, but
65 WITHOUT ANY WARRANTY; without even the implied warranty of
66 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
67 Lesser General Public License for more details.
68
69 You should have received a copy of the GNU Lesser General Public
70 License along with this library; if not, write to the Free Software
71 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
72 02110-1301 USA
73
74
75
76libnbd-1.10.1 2021-10-25 nbd_get_protocol(3)