1<h2>device_write</h2>
2<hr>
3<p>
4<strong>Function</strong> - Write a sequence of bytes to a specific device.
5<h3>SYNOPSIS</h3>
6<pre>
7<strong>#include&ltdevice/device.h&gt</strong>
8
9<strong>kern_return_t   device_write</strong>
10                <strong>(device_t</strong>                                <var>device</var>,
11                 <strong>mach_port_t</strong>                         <var>reply_port</var>,
12                 <strong>dev_mode_t</strong>                                <var>mode</var>,
13                 <strong>recnum_t</strong>                                <var>recnum</var>,
14                 <strong>io_buf_ptr_t</strong>                              <var>data</var>,
15                 <strong>mach_msg_type_number_t</strong>              <var>data_count</var>,
16                 <strong>io_buf_len_t</strong>                      <var>io_buf_len_t</var><strong>);</strong>
17
18
19<strong>#include&ltdevice/device_request.h&gt</strong>
20
21<strong>kern_return_t   device_write_request</strong>
22                <strong>(mach_port_t</strong>                             <var>device</var>,
23                 <strong>mach_port_t</strong>                         <var>reply_port</var>,
24                 <strong>dev_mode_t</strong>                                <var>mode</var>,
25                 <strong>recnum_t</strong>                                <var>recnum</var>,
26                 <strong>io_buf_ptr_t</strong>                              <var>data</var>,
27                 <strong>mach_msg_type_number_t</strong>              <var>data_count</var><strong>);</strong>
28
29
30<strong>kern_return_t   ds_device_write_reply</strong>
31                <strong>(mach_port_t</strong>                         <var>reply_port</var>,
32                 <strong>kern_return_t</strong>                      <var>return_code</var>,
33                 <strong>io_buf_len_t</strong>                     <var>bytes_written</var><strong>);</strong>
34</pre>
35<h3>PARAMETERS</h3>
36<dl>
37<p>
38<dt> <var>device</var> 
39<dd>
40[in device send right]
41A device port to the device to be written.
42<p>
43<dt> <var>reply_port</var> 
44<dd>
45[in reply receive (to be converted to send-once) right]
46The port to 
47which the reply message is to be sent.
48<p>
49<dt> <var>mode</var> 
50<dd>
51[in scalar]
52I/O mode value.  Meaningful options are:
53<dl>
54<p>
55<dt> <strong>D_NOWAIT</strong>
56<dd>
57Do not wait for I/O completion.
58</dl>
59<p>
60<dt> <var>recnum</var> 
61<dd>
62[in scalar]
63Record number to be written.
64<p>
65<dt> <var>data</var> 
66<dd>
67[pointer to in array of bytes]
68Data bytes to be written.
69<p>
70<dt> <var>data_count</var> 
71<dd>
72[in scalar]
73Number of data bytes to be written.
74<p>
75<dt> <var>return_code</var> 
76<dd>
77[in scalar]
78The return status code from the write.
79<p>
80<dt> <var>bytes_written</var> 
81<dd>
82[out scalar, in for asynchronous form]
83Size of data transfer.
84</dl>
85<h3>DESCRIPTION</h3>
86<p>
87The <strong>device_write</strong> function writes a sequence of bytes
88to a device object.  The 
89meaning of <var>recnum</var> as well as the specific operation performed is device
90dependent.
91<h3>RETURN VALUES</h3>
92<p>
93Only generic errors apply.
94<h3>RELATED INFORMATION</h3>
95<p>
96Functions:
97<a href="device_write_inband.html"><strong>device_write_inband</strong></a>,
98<a href="device_reply_server.html"><strong>device_reply_server</strong></a>.
99