Platform SDK: Performance Monitoring

PdhVbOpenQuery

The PdhVbOpenQuery function creates and initializes a unique query structure that is used to manage the collection of performance data.

PdhVbOpenQuery(
  ByRef QueryHandle as Long  
) as Long

QueryHandle: A variable that is cleared (equals 0) before the function is called and, if the function is successful, contains the unique ID of the query that is created and opened. This handle is used in the subsequent calls to other PDH functions to identify the query.

If the function succeeds, it returns a Long integer equal to ERROR_SUCCESS and a new handle in the QueryHandle variable.

If the function fails, the return value is a PDH error status defined in PDHDefs.txt. The following are possible error values.

Error value	Description
PDH_INVALID_ARGUMENT	The argument is invalid or incorrect.
PDH_MEMORY_ALLOCATION_FAILURE	A temporary memory buffer could not be allocated.

Windows NT/2000: Requires Windows NT 4.0 or later.
Library: Use Pdh.lib.