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7<title>MPDSGetData</title>
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10<body>
11<h1>MPDSGetData</h1>
12
13<h2>C Specification</h2>
14<p>
15<dl>
16  <dd><pre><code>#include &lt;revolution/mp.h&gt;</code></pre>
17  </dd>
18  <dd><pre><code>const u8* MPDSGetData ( const <a href="MPDSContext.html">MPDSContext</a>* <i><b>context</b></i>, const <a href="MPDSDataSet.html">MPDSDataSet</a> <i><b>dataSet</b></i>, u32 <i><b>aid</b></i> );</code></pre>
19  </dd>
20</dl>
21</p>
22
23<h2>Arguments</h2>
24<p>
25<table border="1">
26  <tr>
27<td valign="top" width="120" bgcolor="#ffffe8"><code><strong><em>context</em></strong></code></td>
28    <td width="520">A pointer to the <a href="MPDSContext.html"><code>MPDSContext</code></a> structure used to maintain the DataSharing status.</td>
29  </tr>
30  <tr>
31    <td valign="top" width="120" bgcolor="#ffffe8"><code><strong><em>dataSet</em></strong></code></td>
32    <td width="520">A pointer to the <a href="MPDSDataSet.html">MPDSDataSet</a> structure used to store shared data.</td>
33  </tr>
34  <tr>
35<td valign="top" width="120" bgcolor="#ffffe8"><code><strong><em>aid</em></strong></code></td>
36    <td width="520">The AID from which data is to be gotten</td>
37  </tr>
38</table>
39</p>
40
41<h2>Return Values</h2>
42
43<P>Returns a pointer to the data sent by the specified AID, from among the shared data. NULL is returned if no data exists or if the process failed in some way.</P>
44
45<h2>Description</h2>
46
47<p>
48Extracts the data sent by a specified AID from the shared data gotten using either the <a href="MPDSStep.html"><code>MPDSStep()</code></a> function or the <a href="MPDSStep.html"><code>MPDSTryStep()</code></a> function and returns a pointer to it.
49</p>
50<p>
51The following would be cases in which NULL would be returned.
52</p>
53<ol>
54  <li>Blank data read immediately after starting DataSharing</li>
55  <li>The child device for the relevant AID is not connected</li>
56  <li>An internal error occurred</li>
57</ol>
58<p>
59Blank data is read immediately after starting once if double mode is disabled, twice if double mode is enabled.
60</p>
61<p>
62You can confirm whether a child device is connected by checking the return value.<br> However, when child devices can connect freely, if another child device connects immediately after one disconnects, the system won't know that one has been swapped for another. <br> One way of dealing with that is to use the <a href="../mp/MPSetEntryFlag.html"><code>MPSetEntryFlag</code>()</a> and <a href="../mp/MPUpdateBeacon.html"><code>MPUpdateBeacon</code>()</a> functions to stop accepting connection from a new child device once the game has begun. <br>
63 In addition, configuring the callback function for the <CODE>mpdsCallback</CODE> field in the <a href="MPDSConfig.html"><code>MPDSConfig</code></a> structure will allow for direct receipt of child device connection and disconnection notifications.</p>
64
65<h2>See Also</h2>
66<p>
67<code><a href="./MPDSStep.html">MPDSStep()</a></code>, <code><a href="./MPDSStep.html">MPDSTryStep()</a></code>
68</p>
69
70<h2>Revision History</h2>
71
72<p>
732007/11/28 Initial version.
74</p>
75
76<hr><p>CONFIDENTIAL</p></body>
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