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1*699cd480SApple OSS Distributions<h2>device_write_async</h2>
2*699cd480SApple OSS Distributions<hr>
3*699cd480SApple OSS Distributions<p>
4*699cd480SApple OSS Distributions<strong>System Trap</strong> - Write a sequence of bytes to a device object.
5*699cd480SApple OSS Distributions<h3>SYNOPSIS</h3>
6*699cd480SApple OSS Distributions<pre>
7*699cd480SApple OSS Distributions<strong>kern_return_t   device_write_async</strong>
8*699cd480SApple OSS Distributions                <strong>(mach_port_t</strong>                             <var>device</var>,
9*699cd480SApple OSS Distributions                 <strong>mach_port_t</strong>                              <var>queue</var>,
10*699cd480SApple OSS Distributions                 <strong>mach_port_t</strong>                         <var>request_id</var>,
11*699cd480SApple OSS Distributions                 <strong>dev_mode_t</strong>                                <var>mode</var>,
12*699cd480SApple OSS Distributions                 <strong>recnum_t</strong>                                <var>recnum</var>,
13*699cd480SApple OSS Distributions                 <strong>io_buf_ptr_t</strong>                              <var>data</var>,
14*699cd480SApple OSS Distributions                 <strong>io_buf_len_t</strong>                      <var>bytes_wanted</var><strong>);</strong>
15*699cd480SApple OSS Distributions</pre>
16*699cd480SApple OSS Distributions<h3>PARAMETERS</h3>
17*699cd480SApple OSS Distributions<dl>
18*699cd480SApple OSS Distributions<p>
19*699cd480SApple OSS Distributions<dt> <var>device</var>
20*699cd480SApple OSS Distributions<dd>
21*699cd480SApple OSS Distributions[in device send right] A device port to the device to be read.
22*699cd480SApple OSS Distributions<p>
23*699cd480SApple OSS Distributions<dt> <var>queue</var>
24*699cd480SApple OSS Distributions<dd>
25*699cd480SApple OSS Distributions[in io_done queue send right] The port returned from
26*699cd480SApple OSS Distributionsio_done_queue_create.
27*699cd480SApple OSS Distributions<p>
28*699cd480SApple OSS Distributions<dt> <var>request_id</var>
29*699cd480SApple OSS Distributions<dd>
30*699cd480SApple OSS Distributions[in send right] An unique request identifier that will be passed back as
31*699cd480SApple OSS Distributionspart of the io_done_result structure.
32*699cd480SApple OSS Distributions<p>
33*699cd480SApple OSS Distributions<dt> <var>mode</var>
34*699cd480SApple OSS Distributions<dd>
35*699cd480SApple OSS Distributions[in scalar] I/O mode value. Meaningful options are:
36*699cd480SApple OSS Distributions<p>
37*699cd480SApple OSS Distributions     <dl>
38*699cd480SApple OSS Distributions<dt> <strong>D_NOWAIT</strong>
39*699cd480SApple OSS Distributions<dd>
40*699cd480SApple OSS DistributionsDo not wait if data is unavailable.
41*699cd480SApple OSS Distributions     </dl>
42*699cd480SApple OSS Distributions<p>
43*699cd480SApple OSS Distributions<dt> <var>recnum</var>
44*699cd480SApple OSS Distributions<dd>
45*699cd480SApple OSS Distributions[in scalar] Record number to be read.
46*699cd480SApple OSS Distributions<p>
47*699cd480SApple OSS Distributions<dt> <var>data</var>
48*699cd480SApple OSS Distributions<dd>
49*699cd480SApple OSS Distributions[pointer to in array of bytes] Data bytes to be written.
50*699cd480SApple OSS Distributions<p>
51*699cd480SApple OSS Distributions<dt> <var>bytes_wanted</var>
52*699cd480SApple OSS Distributions<dd>
53*699cd480SApple OSS Distributions[in scalar] Size of data transfer.
54*699cd480SApple OSS Distributions</dl>
55*699cd480SApple OSS Distributions<h3>DESCRIPTION</h3>
56*699cd480SApple OSS Distributions<p>
57*699cd480SApple OSS DistributionsThe <strong>device_write_async</strong> function enqueues a write operation for a
58*699cd480SApple OSS Distributionssequence of bytes to a device object. The meaning of recnum as well as
59*699cd480SApple OSS Distributionsthe specific operation performed is device dependent.
60*699cd480SApple OSS Distributions<h3>RETURN VALUES</h3>
61*699cd480SApple OSS Distributions<p>
62*699cd480SApple OSS Distributions<strong>device_write_async</strong> returns only invalid parameter errors.
63*699cd480SApple OSS Distributions<h3>RELATED INFORMATION</h3>
64*699cd480SApple OSS Distributions<p>
65*699cd480SApple OSS DistributionsFunctions:
66*699cd480SApple OSS Distributions<a href="device_read_async_inband.html"><strong>device_read_async_inband</strong></a>,
67*699cd480SApple OSS Distributions<a href="DR_overwrite_async.html"><strong>device_read_overwrite_async</strong></a>,
68*699cd480SApple OSS Distributions<a href="device_write_async_inband.html"><strong>device_write_async_inband</strong></a>,
69*699cd480SApple OSS Distributions<a href="io_done_queue_create.html"><strong>io_done_queue_create</strong></a>.
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