1nbd_set_debug_callback(3)           LIBNBD           nbd_set_debug_callback(3)
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NAME

6       nbd_set_debug_callback - set the debug callback
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SYNOPSIS

9        #include <libnbd.h>
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11        typedef struct {
12          int (*callback) (void *user_data, const char *context,
13                           const char *msg);
14          void *user_data;
15          void (*free) (void *user_data);
16        } nbd_debug_callback;
17
18        int nbd_set_debug_callback (
19              struct nbd_handle *h,
20              nbd_debug_callback debug_callback
21            );
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DESCRIPTION

24       Set the debug callback.  This function is called when the library emits
25       debug messages, when debugging is enabled on a handle.  The callback
26       parameters are "user_data" passed to this function, the name of the
27       libnbd function emitting the debug message ("context"), and the message
28       itself ("msg").  If no debug callback is set on a handle then messages
29       are printed on "stderr".
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31       The callback should not call "nbd_*" APIs on the same handle since it
32       can be called while holding the handle lock and will cause a deadlock.
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RETURN VALUE

35       If the call is successful the function returns 0.
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ERRORS

38       On error -1 is returned.
39
40       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details
41       of the error.
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43       The following parameters must not be NULL: "h".  For more information
44       see "Non-NULL parameters" in libnbd(3).
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VERSION

47       This function first appeared in libnbd 1.0.
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49       If you need to test if this function is available at compile time check
50       if the following macro is defined:
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52        #define LIBNBD_HAVE_NBD_SET_DEBUG_CALLBACK 1
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SEE ALSO

55       nbd_create(3), libnbd(3).
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AUTHORS

58       Eric Blake
59
60       Richard W.M. Jones
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63       Copyright Red Hat
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LICENSE

66       This library is free software; you can redistribute it and/or modify it
67       under the terms of the GNU Lesser General Public License as published
68       by the Free Software Foundation; either version 2 of the License, or
69       (at your option) any later version.
70
71       This library is distributed in the hope that it will be useful, but
72       WITHOUT ANY WARRANTY; without even the implied warranty of
73       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
74       Lesser General Public License for more details.
75
76       You should have received a copy of the GNU Lesser General Public
77       License along with this library; if not, write to the Free Software
78       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
79       02110-1301 USA
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83libnbd-1.16.5                     2023-09-26         nbd_set_debug_callback(3)
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