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= nng_aio_set_iov(3)
//
// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
// Copyright 2018 Capitar IT Group BV <info@capitar.com>
//
// This document is supplied under the terms of the MIT License, a
// copy of which should be located in the distribution where this
// file was obtained (LICENSE.txt). A copy of the license may also be
// found online at https://opensource.org/licenses/MIT.
//
== 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.5#,`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.3#,nng_aio_alloc(3)>>,
<<nng_aio_cancel.3#,nng_aio_cancel(3)>>,
<<nng_aio_count.3#,nng_aio_count(3)>>,
<<nng_aio_result.3#,nng_aio_result(3)>>,
<<nng_aio.5#,nng_aio(5)>>,
<<nng_iov.5#,nng_iov(5)>>,
<<nng.7#,nng(7)>>
|
