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7    <title>ReadAsync</title>
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10    <h1><CODE><a href="../../../nw/Overview.html">nw</a>::<a href="../../../nw/io/Overview.html">io</a>::<a href="../../../nw/io/IOStream/Overview.html">IOStream</a>::ReadAsync</CODE> Member Function</h1>
11    <h2>Syntax</h2>
12    <div class="section">
13      <pre class="definition">
14virtual bool ReadAsync(
15     void*            buf,
16     <span>u32</span> length,
17     <a href="../../../nw/io/IOStream/IOStreamCallback.html">IOStreamCallback</a> callback,
18     void*           arg
19);
20</pre>
21    </div>
22    <h2>Arguments</h2>
23    <div class="section">
24      <table class="arguments">
25        <thead>
26          <tr>
27            <td width="15" />
28            <th>Name</th>
29            <td>Description</td>
30          </tr>
31        </thead>
32        <tr>
33          <td>out</td>
34          <th>buf</th>
35          <td>Pointer to the buffer where data to be read is stored. The alignment of this data must match the alignment obtained using the <a href="../../../nw/io/IOStream/GetBufferAlign.html"><CODE>GetBufferAlign</CODE></A> function.</td>
36        </tr>
37        <tr>
38          <td>in</td>
39          <th>length</th>
40          <td>Data size to be read. The alignment of this data must match the alignment obtained using the <a href="../../../nw/io/IOStream/GetSizeAlign.html"><CODE>GetSizeAlign</CODE></A> function.</td>
41        </tr>
42        <tr>
43          <td>in</td>
44          <th>callback</th>
45          <td>Registers the callback function to be used when asynchronous processing has finished. If this is <CODE>NULL</CODE>, no callback is invoked.</td>
46        </tr>
47        <tr>
48          <td>in</td>
49          <th>arg</th>
50          <td>Registers parameters returned by the callback function as arguments when asynchronous processing has completed.</td>
51        </tr> </table>
52    </div>
53    <h2>Return Values</h2>
54    <div class="section">Returns <CODE>TRUE</CODE> if the command was executed normally.<br /> Returns <CODE>FALSE</CODE> if the command was not issued.<br /> If the command could not be issued, no callback is invoked. </div>
55    <h2>Description</h2>
56    <div class="section">
57      <p>Reads data from the stream (asynchronous process).</p><p>It fails on ASSERT when <CODE>false</CODE> is returned by both the <CODE><a href="../../../nw/io/IOStream/CanRead.html">nw::io::IOStream::CanRead</a></CODE> function and the <CODE><a href="../../../nw/io/IOStream/CanAsync.html">nw::io::IOStream::CanAsync</a></CODE>function. <br /> During asynchronous processing the <CODE><a href="../../../nw/io/IOStream/IsBusy.html">nw::io::IOStream::IsBusy</a></CODE> function returns <CODE>true</CODE>, and during that time other asynchronous processes cannot be called.<br /> When processing completes, the registered callback is invoked provided the <CODE>callback</CODE> argument is not <CODE>NULL</CODE>.<BR> It is also possible to wait for asynchronous processing to end using the <CODE><a href="../../../nw/io/IOStream/WaitAsync.html">nw::io::IOStream::WaitAsync</a></CODE> function.</p></div>
58    <h2>See Also</h2>
59    <div class="section">
60      <p class="reference"><a href="../../../nw/io/IOStream/Read.html">nw::io::IOStream::Read</a><br /><a href="../../../nw/io/IOStream/IsBusy.html">nw::io::IOStream::IsBusy</a><br /><a href="../../../nw/io/IOStream/WaitAsync.html">nw::io::IOStream::WaitAsync</a><br /><a href="../../../nw/io/IOStream/CanRead.html">nw::io::IOStream::CanRead</a><br /><a href="../../../nw/io/IOStream/CanAsync.html">nw::io::IOStream::CanAsync</a><br /><a href="../../../nw/io/IOStream/GetBufferAlign.html">nw::io::IOStream::GetBufferAlign</a><br /><a href="../../../nw/io/IOStream/GetSizeAlign.html">nw::io::IOStream::GetSizeAlign</a><br /> </p>
61    </div>
62    <h2>Revision History</h2>
63    <div class="section">
64      <dl class="history">
65        <dt>2009/10/20</dt>
66        <dd>Initial version.<br />
67        </dd>
68      </dl>
69    </div>
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72