1nbd_aio_opt_set_meta_context_queries(L3I)BNnBbDd_aio_opt_set_meta_context_queries(3)
2
6 nbd_aio_opt_set_meta_context_queries - select specific meta contexts,
7 with explicit query list
8
10 #include <libnbd.h>
11 typedef struct {
13 int (*callback) (void *user_data, const char *name);
14 void *user_data;
15 void (*free) (void *user_data);
16 } nbd_context_callback;
17 typedef struct {
19 int (*callback) (void *user_data, int *error);
20 void *user_data;
21 void (*free) (void *user_data);
22 } nbd_completion_callback;
23 int nbd_aio_opt_set_meta_context_queries (
25 struct nbd_handle *h, char **queries,
26 nbd_context_callback context_callback,
27 nbd_completion_callback completion_callback
28 );
29
31 Request that the server supply all recognized meta contexts passed in
32 through "queries", in conjunction with the export previously specified
33 by the most recent nbd_set_export_name(3) or nbd_connect_uri(3). This
34 can only be used if nbd_set_opt_mode(3) enabled option mode. Normally,
35 this function is redundant, as nbd_opt_go(3) automatically does the
36 same task if structured replies have already been negotiated. But
37 manual control over meta context requests can be useful for fine-
38 grained testing of how a server handles unusual negotiation sequences.
39 Often, use of this function is coupled with
40 nbd_set_request_meta_context(3) to bypass the automatic context request
41 normally performed by nbd_opt_go(3).
42 To determine when the request completes, wait for
44 nbd_aio_is_connecting(3) to return false. Or supply the optional
45 "completion_callback" which will be invoked as described in "Completion
46 callbacks" in libnbd(3), except that it is automatically retired
47 regardless of return value. Note that detecting whether the server
48 returns an error (as is done by the return value of the synchronous
49 counterpart) is only possible with a completion callback.
50
52 This call returns an integer ≥ 0.
53
55 On error -1 is returned.
56 Refer to "ERROR HANDLING" in libnbd(3) for how to get further details
58 of the error.
59 The following parameters must not be NULL: "h", "queries". For more
61 information see "Non-NULL parameters" in libnbd(3).
62
64 The handle must be negotiating, otherwise this call will return an
65 error.
66
68 This function first appeared in libnbd 1.16.
69 If you need to test if this function is available at compile time check
71 if the following macro is defined:
72 #define LIBNBD_HAVE_NBD_AIO_OPT_SET_META_CONTEXT_QUERIES 1
74
76 nbd_aio_is_connecting(3), nbd_aio_opt_set_meta_context(3),
77 nbd_connect_uri(3), nbd_create(3), nbd_opt_go(3),
78 nbd_opt_set_meta_context_queries(3), nbd_set_export_name(3),
79 nbd_set_opt_mode(3), nbd_set_request_meta_context(3), libnbd(3).
80
82 Eric Blake
83 Richard W.M. Jones
85
87 Copyright Red Hat
88
90 This library is free software; you can redistribute it and/or modify it
91 under the terms of the GNU Lesser General Public License as published
92 by the Free Software Foundation; either version 2 of the License, or
93 (at your option) any later version.
94 This library is distributed in the hope that it will be useful, but
96 WITHOUT ANY WARRANTY; without even the implied warranty of
97 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
98 Lesser General Public License for more details.
99 You should have received a copy of the GNU Lesser General Public
101 License along with this library; if not, write to the Free Software
102 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
103 02110-1301 USA
104libnbd-1.16.5 2023-0n9b-d2_6aio_opt_set_meta_context_queries(3)