<div class="content"><p>The _PERF_COUNTER_HEADER structure is used at the beginning
of a counter header block.</p><dl>
<dd>
<div><pre> typedef struct _PERF_COUNTER_HEADER {
   unsigned long dwStatus;
   unsigned long dwType;
   unsigned long dwSize;
   unsigned long Reserved;
 } PERF_COUNTER_HEADER,
  *PPERFCOUNTERHEADER;
</pre></div>
</dd></dl><p><b>dwStatus:</b>  A Win32 error code that
indicates whether the operation was successful. Win32 error codes are specified
in <a href="../ms-erref/1bc92ddf-b79e-413c-bbaa-99a5281a6c90" data-linktype="relative-path">[MS-ERREF]</a>.</p><p><b>dwType:</b>  The <a href="da82a046-4e10-46ab-8da9-3d24bb48a2b2#gt_35645a67-9e0b-4c05-b2d9-3b2b25f2beac" data-linktype="relative-path">performance counter</a> type.
The value MUST be one of the following.</p><dl>
<dd>
<table><thead>
  <tr>
   <th>
   <p>Value</p>
   </th>
   <th>
   <p>Meaning</p>
   </th>
  </tr>
 </thead><tbody><tr>
  <td>
  <p>PERF_ERROR_RETURN</p>
  <p>0x00000000</p>
  </td>
  <td>
  <p>An error occurred when the performance counter value
  was queried.</p>
  </td>
 </tr><tr>
  <td>
  <p>PERF_SINGLE_COUNTER</p>
  <p>0x00000001</p>
  </td>
  <td>
  <p>The query returned a single-instance performance
  counter value.</p>
  </td>
 </tr><tr>
  <td>
  <p>PERF_MULTI_COUNTERS </p>
  <p>0x00000002</p>
  </td>
  <td>
  <p>The query returned multiple performance counter
  values.</p>
  </td>
 </tr><tr>
  <td>
  <p>PERF_MULTI_INSTANCES</p>
  <p>0x00000004</p>
  </td>
  <td>
  <p>The query returned values from multiple instances of a
  performance counter.</p>
  </td>
 </tr><tr>
  <td>
  <p>PERF_COUNTERSET</p>
  <p>0x00000006</p>
  </td>
  <td>
  <p>The query returned the values of all instances of all
  performance counters that belong to the <a href="da82a046-4e10-46ab-8da9-3d24bb48a2b2#gt_5ad9937c-a24e-4274-92c8-50ff5f97bf19" data-linktype="relative-path">counterset</a>.</p>
  </td>
 </tr></tbody></table>
</dd></dl><p><b>dwSize:</b>  The size, in bytes, of the
structure and data.</p><p><b>Reserved:</b>  MUST be set to 0, and MUST be
ignored on receipt.</p></div>