1<h2>device_read_inband</h2>
2<hr>
3<p>
4<strong>Function</strong> - Read a sequence of bytes "inband" from a device object.
5<h3>SYNOPSIS</h3>
6<pre>
7<strong>#include&ltdevice/device.h&gt</strong>
8
9<strong>kern_return_t   device_read_inband</strong>
10                <strong>(mach_port_t</strong>                             <var>device</var>,
11                 <strong>dev_mode_t</strong>                                <var>mode</var>,
12                 <strong>recnum_t</strong>                                <var>recnum</var>,
13                 <strong>io_buf_len_t</strong>                      <var>bytes_wanted</var>,
14                 <strong>io_buf_ptr_inband_t</strong>                       <var>data</var>,
15                 <strong>mach_msg_type_number_t</strong>             <var>*data_count</var><strong>);</strong>
16
17
18<strong>#include&ltdevice/device_request.h&gt</strong>
19
20<strong>kern_return_t   device_read_request_inband</strong>
21                <strong>(mach_port_t</strong>                             <var>device</var>,
22                 <strong>mach_port_t</strong>                         <var>reply_port</var>,
23                 <strong>dev_mode_t</strong>                                <var>mode</var>,
24                 <strong>recnum_t</strong>                                <var>recnum</var>,
25                 <strong>io_buf_len_t</strong>                      <var>bytes_wanted</var><strong>);</strong>
26
27
28<strong>kern_return_t   ds_device_read_reply_inband</strong>
29                <strong>(mach_port_t</strong>                         <var>reply_port</var>,
30                 <strong>kern_return_t</strong>                      <var>return_code</var>,
31                 <strong>io_buf_ptr_inband_t</strong>                       <var>data</var>,
32                 <strong>mach_msg_type_number_t</strong>              <var>data_count</var><strong>);</strong>
33</pre>
34<h3>PARAMETERS</h3>
35<dl>
36<p>
37<dt> <var>device</var> 
38<dd>
39[in device send right]
40A device port to the device to be read.
41<p>
42<dt> <var>reply_port</var> 
43<dd>
44[in reply receive (to be converted to send-once) right]
45The port to 
46which the reply message is to be sent.
47<p>
48<dt> <var>mode</var> 
49<dd>
50[in scalar]
51I/O mode value.  Meaningful options are:
52<dl>
53<p>
54<dt> <strong>D_NOWAIT</strong>
55<dd>
56Do not wait if data is unavailable.
57</dl>
58<p>
59<dt> <var>recnum</var> 
60<dd>
61[in scalar]
62Record number to be read.
63<p>
64<dt> <var>bytes_wanted</var> 
65<dd>
66[in scalar]
67Size of data transfer.
68<p>
69<dt> <var>return_code</var> 
70<dd>
71[in scalar]
72The return status code from the read.
73<p>
74<dt> <var>data</var> 
75<dd>
76[out array of bytes, in for asynchronous form]
77Returned data bytes.
78<p>
79<dt> <var>data_count</var> 
80<dd>
81[out scalar, in for asynchronous form]
82Number of returned data bytes.
83</dl>
84<h3>DESCRIPTION</h3>
85<p>
86The <strong>device_read_inband</strong> function reads a sequence of bytes
87from a device object.  The 
88meaning of <var>recnum</var> as well as the specific operation performed is device
89dependent.  This call differs from <strong>device_read</strong> in that
90the returned bytes are returned 
91"inband" in the reply IPC message.
92<h3>RETURN VALUES</h3>
93<p>
94Only generic errors apply.
95<h3>RELATED INFORMATION</h3>
96<p>
97Functions:
98<a href="device_read.html"><strong>device_read</strong></a>,
99<a href="device_read_overwrite.html"><strong>device_read_overwrite</strong></a>,
100<a href="device_reply_server.html"><strong>device_reply_server</strong></a>.
101