1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
= nng_aio_set_iov(3)
:doctype: manpage
:manmanual: nng
:mansource: nng
:manvolnum: 3
:copyright: Copyright 2018 mailto:info@staysail.tech[Staysail Systems, Inc.] + \
Copyright 2018 mailto:info@capitar.com[Capitar IT Group BV] + \
{blank} + \
This document is supplied under the terms of the \
https://opensource.org/licenses/MIT[MIT License].
== NAME
nng_aio_set_iov - set scatter/gather vector
== SYNOPSIS
[source, c]
-----------
#include <nng/nng.h>
int nng_aio_set_iov(nng_aio *aio, unsigned int niov, nng_iov *iov);
-----------
== DESCRIPTION
The `nng_aio_set_iov()` function sets a scatter/gather vector _iov_ on the
handle _aio_.
The _iov_ is a pointer to an array of _niov_ `nng_iov` structures, which have
the following definition:
[source, c]
----
typedef struct nng_iov {
void * iov_buf;
size_t iov_len;
};
----
The _iov_ is copied into storage in the _aio_ itself, so that callers
may use stack allocated `nng_iov` structures. The values pointed to
by the `iov_buf` members are *not* copied by this function though.
Up to four `nng_iov` members may be supplied without causing any
allocations, and thus this operation is guaranteed to succeed for
values of _niov_ less than four.
More than four (4) `nng_iov` members may be supplied, but this may require
heap allocations, and so the operation may fail with `NNG_ENOMEM`.
Additionally, not every operation can support longer vectors; the
actual limit is determined by the system, but is generally at least
sixteen (16). Furthermore, values for _niov_ larger than sixty-four (64) will
generally result in `NNG_EINVAL`.
== RETURN VALUES
This function returns 0 on success, and non-zero otherwise.
== ERRORS
`NNG_ENOMEM`:: Insufficient free memory to perform operation.
`NNG_EINVAL`:: Value of specified _niov_ is too large.
== SEE ALSO
<<nng_aio_alloc#,nng_aio_alloc(3)>>,
<<nng_aio_cancel#,nng_aio_cancel(3)>>,
<<nng_aio_count#,nng_aio_count(3)>>,
<<nng_aio_result#,nng_aio_result(3)>>,
<<nng#,nng(7)>>
== COPYRIGHT
{copyright}
|
