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<h2 id="os_mbuf_memcmp"><font color="#F2853F" style="font-size:24pt">os_mbuf_memcmp</font></h2>
<div class="codehilite" style="background: #ffffff"><pre style="line-height: 125%;"><span></span><code><span style="color: #A90D91">int</span> <span style="color: #000000">os_mbuf_memcmp</span>(<span style="color: #A90D91">const</span> <span style="color: #A90D91">struct</span> <span style="color: #3F6E75">os_mbuf</span> <span style="color: #000000">*om</span>, <span style="color: #A90D91">int</span> <span style="color: #000000">off</span>, <span style="color: #A90D91">const</span> <span style="color: #A90D91">void</span> <span style="color: #000000">*data</span>, <span style="color: #A90D91">int</span> <span style="color: #000000">len</span>)
</code></pre></div>
<p>Performs a memory compare of the specified region of an mbuf chain against a flat buffer.</p>
<p><br></p>
<h4 id="arguments">Arguments</h4>
<table>
<thead>
<tr>
<th>Arguments</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td><code>om</code></td>
<td>Pointer to mbuf</td>
</tr>
<tr>
<td><code>off</code></td>
<td>Offset, in bytes, from start of mbuf to start of comparison</td>
</tr>
<tr>
<td><code>data</code></td>
<td>Pointer to flat data buffer to compare</td>
</tr>
<tr>
<td><code>len</code></td>
<td>Number of bytes to compare</td>
</tr>
</tbody>
</table>
<p><br></p>
<h4 id="returned-values">Returned values</h4>
<p>A value of zero means the memory regions are identical; all other values represent either an error or a value returned from memcmp. </p>
<p><br></p>
<h4 id="notes">Notes</h4>
<p>This function will compare bytes starting from <code>off</code> bytes from the start of the mbuf chain with a data buffer.</p>
<p><br></p>
<h4 id="example">Example</h4>
<div class="codehilite" style="background: #ffffff"><pre style="line-height: 125%;"><span></span><code> <span style="color: #A90D91">int</span> <span style="color: #000000">rc</span>;
<span style="color: #A90D91">struct</span> <span style="color: #3F6E75">os_mbuf</span> <span style="color: #000000">*om</span>;
<span style="color: #A90D91">uint8_t</span> <span style="color: #000000">my_data_buffer</span>[<span style="color: #1C01CE">32</span>];
<span style="color: #177500">/* Get a packet header mbuf with a user header in it */</span>
<span style="color: #000000">rc</span> <span style="color: #000000">=</span> <span style="color: #000000">os_mbuf_memcmp</span>(<span style="color: #000000">om</span>, <span style="color: #1C01CE">0</span>, <span style="color: #000000">my_data_buffer</span>, <span style="color: #1C01CE">32</span>);
<span style="color: #A90D91">if</span> (<span style="color: #000000">!rc</span>) {
<span style="color: #177500">/* &quot;my_data_buffer&quot; and the data from offset 0 in the mbuf chain are identical! */</span>
}
</code></pre></div>
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