1<h2>device_open</h2>
2<hr>
3<p>
4<strong>Function</strong> - Establish a connection to a device.
5<h3>SYNOPSIS</h3>
6<pre>
7<strong>#include&ltdevice/device.h&gt</strong>
8
9<strong>kern_return_t   device_open</strong>
10                <strong>(mach_port_t</strong>                        <var>master_port</var>,
11                 <strong>mach_port_t</strong>                             <var>ledger</var>,
12                 <strong>dev_mode_t</strong>                                <var>mode</var>,
13                 <strong>security_token_t</strong>                   <var>security_id</var>,
14                 <strong>dev_name_t</strong>                                <var>name</var>,
15                 <strong>mach_port_t</strong>                             <var>device</var><strong>);</strong>
16
17
18<strong>#include&ltdevice/device_request.h&gt</strong>
19
20<strong>kern_return_t   device_open_request</strong>
21                <strong>(mach_port_t</strong>                        <var>master_port</var>,
22                 <strong>mach_port_t</strong>                         <var>reply_port</var>,
23                 <strong>mach_port_t</strong>                             <var>ledger</var>,
24                 <strong>dev_mode_t</strong>                                <var>mode</var>,
25                 <strong>security_token_t</strong>                   <var>security_id</var>,
26                 <strong>dev_name_t</strong>                                <var>name</var><strong>);</strong>
27
28
29<strong>kern_return_t   ds_device_open_reply</strong>
30                <strong>(mach_port_t</strong>                         <var>reply_port</var>,
31                 <strong>kern_return_t</strong>                      <var>return_code</var>,
32                 <strong>mach_port_t</strong>                             <var>device</var><strong>);</strong>
33</pre>
34<h3>PARAMETERS</h3>
35<dl>
36<p>
37<dt> <var>master_port</var> 
38<dd>
39[in device-master send right]
40The master device port.  This port is
41provided to the bootstrap task.
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 a reply is to be sent when the device is open.
48<p>
49<dt> <var>ledger</var> 
50<dd>
51[pointer to a ledger send right]
52Resource ledger from which the device will draw its resources.
53<p>
54<dt> <var>mode</var> 
55<dd>
56[in scalar]
57Opening mode.  This is the bit-wise <strong>OR</strong> of the following
58values:
59<dl>
60<p>
61<dt> <strong>D_READ</strong>
62<dd>
63Read access
64<p>
65<dt> <strong>D_WRITE</strong>
66<dd>
67Write access
68<p>
69<dt> <strong>D_NODELAY</strong>
70<dd>
71Do not delay on open
72</dl>
73<p>
74<dt> <var>security_id</var> 
75<dd>
76[in scalar]
77The security ID that tasks attempting to use this device port 
78must have.  A zero value indicates all identities.
79<p>
80<dt> <var>name</var> 
81<dd>
82[pointer to in array of <var>char</var>]
83Name of the device to open.
84<p>
85<dt> <var>return_code</var> 
86<dd>
87[in scalar]
88Status of the open.
89<p>
90<dt> <var>device</var> 
91<dd>
92[out device send right, in for asynchronous form]
93The returned device 
94port.
95</dl>
96<h3>DESCRIPTION</h3>
97<p>
98The <strong>device_open</strong> function opens a device object.  The
99open operation of the
100device is invoked, if the device is not already open.  The open
101count for the device 
102is incremented.  Each open for a device returns a port, the allowed
103operations upon which being governed by <var>mode</var>.  The port is not
104distinct.
105<h3>RETURN VALUES</h3>
106<p>
107Only generic errors apply.
108<h3>RELATED INFORMATION</h3>
109<p>
110Functions:
111<a href="device_close.html"><strong>device_close</strong></a>,
112<a href="device_reply_server.html"><strong>device_reply_server</strong></a>.
113