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13
14<h1 align="left">VISetPostRetraceCallback</h1>
15
16<h2>Syntax</h2>
17<dl><dd><pre class="construction">#include &lt;revolution/vi.h&gt;
18
19typedef void (*VIRetraceCallback)(u32 retraceCount);
20
21VIRetraceCallback VISetPostRetraceCallback(VIRetraceCallback callback);
22</pre></dd></dl>
23
24<h2>Arguments</h2>
25<TABLE class="arguments" border="1" >
26<TBODY>
27  <tr>
28<th>callback</th>
29<td>A pointer to the post-retrace callback function.</td>
30  </tr>
31</TBODY>
32</table>
33
34<h2>Return Values</h2>
35<p>Pointer to the previous callback function.</p>
36
37<h2>Description</h2>
38<p>This function sets the post-retrace callback. That callback is a function called after the VI device driver's retrace interrupt handler sets the VI registers.</p>
39
40<p>It returns the pointer to the previous callback function.</p>
41
42<p>Specifying <CODE>NULL</CODE> for <SPAN class="argument">callback</SPAN> means no callback is specified as the post-retrace callback. Similarly, <CODE>NULL</CODE> is returned when no callback has been registered before. Since no callback is specified by default, the first call to this function should return <CODE>NULL</CODE>. You can cancel a callback function you set previously by specifying <CODE>NULL</CODE> for <SPAN class="argument">callback</SPAN>.</p>
43
44<p>The retrace count, which is passed to the callback function as an argument, is incremented once every 1/60 second in NTSC/EURGB60 modes (or once every 1/50 second in PAL mode).</p>
45
46<h2>See Also</h2>
47<P class="reference">
48<a href="VISetPreRetraceCallback.html">VISetPreRetraceCallback</a>,
49<a href="VIWaitForRetrace.html">VIWaitForRetrace</a>
50</p>
51
52<h2>Revision History</h2>
53<p>
542007/12/03 Deleted the MPAL description.<br>2006/03/01 Initial version.<br>
55</p>
56
57<hr><p>CONFIDENTIAL</p></body>
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