<div class="content"><p>The DATA_EXTENSION_PREFIX structure contains a data
component size and type. The structure of DATA_EXTENSION_PREFIX is as follows.</p><dl>
<dd>
<div><pre> typedef struct _DATA_EXTENSION_PREFIX {
   ULONG Size;
   LONG Type;
 } DATA_EXTENSION_PREFIX,
  *PDATA_EXTENSION_PREFIX;
</pre></div>
</dd></dl><p><b>Size:</b>   A 32-bit, unsigned integer
that specifies the size of the data component, including this prefix.</p><p><b>Type:</b>   A 32-bit, unsigned integer
that specifies the type of the data component. It MUST be one of the following
values.</p><dl>
<dd>
<table><thead>
  <tr>
   <th>
   <p>Value</p>
   </th>
   <th>
   <p>Meaning</p>
   </th>
  </tr>
 </thead><tbody><tr>
  <td>
  <p>0x00000000</p>
  </td>
  <td>
  <p>Terminates a data extension record. MUST NOT be used.</p>
  </td>
 </tr><tr>
  <td>
  <p>0x00000001</p>
  </td>
  <td>
  <p>Data checksum record using an <a href="2e457199-2dc1-46c3-8aa6-b2d8e016f95c#gt_05caca9b-e062-4a6b-8c99-cd5e23f38a11" data-linktype="relative-path">MD5 hash</a>.</p>
  </td>
 </tr><tr>
  <td>
  <p>0x00000002</p>
  </td>
  <td>
  <p>Data retry time-out record.</p>
  </td>
 </tr></tbody></table>
</dd></dl><p> </p></div>