1nbd_aio_pwrite(3)                   LIBNBD                   nbd_aio_pwrite(3)
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NAME

6       nbd_aio_pwrite - write to the NBD server
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SYNOPSIS

9        #include <libnbd.h>
10
11        typedef struct {
12          int (*callback) (void *user_data, int *error);
13          void *user_data;
14          void (*free) (void *user_data);
15        } nbd_completion_callback;
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17        int64_t nbd_aio_pwrite (struct nbd_handle *h,
18                                const void *buf, size_t count,
19                                uint64_t offset,
20                                nbd_completion_callback completion_callback,
21                                uint32_t flags);
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DESCRIPTION

24       Issue a write command to the NBD server.
25
26       To check if the command completed, call nbd_aio_command_completed(3).
27       Or supply the optional "completion_callback" which will be invoked as
28       described in "Completion callbacks" in libnbd(3).
29
30       Note that you must ensure "buf" is valid until the command has
31       completed.  Other parameters behave as documented in nbd_pwrite(3).
32
33       By default, libnbd will reject attempts to use this function with
34       parameters that are likely to result in server failure, such as
35       requesting an unknown command flag.  The nbd_set_strict_mode(3)
36       function can be used to alter which scenarios should await a server
37       reply rather than failing fast.
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RETURN VALUE

40       This call returns the 64 bit cookie of the command.  The cookie is ≥ 1.
41       Cookies are unique (per libnbd handle, not globally).
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ERRORS

44       On error "-1" is returned.
45
46       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details
47       of the error.
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HANDLE STATE

50       The handle must be connected with the server, otherwise this call will
51       return an error.
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VERSION

54       This function first appeared in libnbd 1.0.
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56       If you need to test if this function is available at compile time check
57       if the following macro is defined:
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59        #define LIBNBD_HAVE_NBD_AIO_PWRITE 1
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SEE ALSO

62       nbd_aio_command_completed(3), nbd_create(3), nbd_is_read_only(3),
63       nbd_pwrite(3), nbd_set_strict_mode(3), "Issuing asynchronous commands"
64       in libnbd(3), libnbd(3).
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AUTHORS

67       Eric Blake
68
69       Richard W.M. Jones
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72       Copyright (C) 2019-2020 Red Hat Inc.
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LICENSE

75       This library is free software; you can redistribute it and/or modify it
76       under the terms of the GNU Lesser General Public License as published
77       by the Free Software Foundation; either version 2 of the License, or
78       (at your option) any later version.
79
80       This library is distributed in the hope that it will be useful, but
81       WITHOUT ANY WARRANTY; without even the implied warranty of
82       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
83       Lesser General Public License for more details.
84
85       You should have received a copy of the GNU Lesser General Public
86       License along with this library; if not, write to the Free Software
87       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
88       02110-1301 USA
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92libnbd-1.6.2                      2021-03-02                 nbd_aio_pwrite(3)
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