<div class="content" name="PERF_COUNTER_HEADER" uuid="43839154-f7c2-4f86-b10a-d6fa145c5337"><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>PERF_ERROR_RETURN 0x00000000</td>
  <td>An error occurred when the performance counter value was queried.</td>
 </tr><tr>
  <td>PERF_SINGLE_COUNTER 0x00000001</td>
  <td>The query returned a single-instance performance counter value.</td>
 </tr><tr>
  <td>PERF_MULTI_COUNTERS 0x00000002</td>
  <td>The query returned multiple performance counter values.</td>
 </tr><tr>
  <td>PERF_MULTI_INSTANCES 0x00000004</td>
  <td>The query returned values from multiple instances of a performance counter.</td>
 </tr><tr>
  <td>PERF_COUNTERSET 0x00000006</td>
  <td>The query returned the values of all instances of all performance counters that belong to the counterset.</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>