PdhComputeCounterStatistics
The PdhComputeCounterStatistics
function computes statistics for a counter from an array of raw values.
PDH_STATUS PdhComputeCounterStatistics(
|
IN HCOUNTER hCounter, |
// handle of the
counter |
|
IN
DWORD dwFormat, |
// format code |
|
IN DWORD dwFirstEntry, |
// first entry in
the array |
|
IN DWORD dwNumEntries, |
// number of
entries in the array |
|
IN PPDH_RAW_COUNTER lpRawValueArray, |
// array of raw
counter values |
|
IN PPDH_STATISTICS data |
// buffer for
counter statistics |
|
); |
|
Parameters
hCounter
The handle of
the counter used for the computation. This determines how the data will be
computed.
dwFormat
The
formatting information sent by the caller to indicate how the calculated value
should be returned. This parameter can be one of the following values:
PDH_FMT_DOUBLE
Return the
calculated value as a double-precision floating point real.
PDH_FMT_LARGE
Return the
calculated value as a 64-bit integer.
PDH_FMT_LONG
Return the
calculated value as a long integer.
The value
selected from the previous table can be combined using the OR operator
with one of the following scaling flags:
PDH_FMT_NOSCALE
Do not apply
the counter s scaling factors in the calculation.
PDH_FMT_1000
Multiply the
final value by 1000.
dwFirstEntry
The
zero-based index of the first raw counter buffer to look at. This value must
point to the oldest entry in the buffer. The PdhComputeCounterStatistics
function starts at this entry and scans through the buffer, wrapping at the
last entry back to the beginning of the buffer and up to the dwFirstEntry-1
entry, which is assumed to be the newest or most recent data.
dwNumEntries
The number of
raw counter entries in the lpRawValueArray buffer.
lpRawValueArray
A pointer to
the raw counter value or values used to compute the counter value. Some
counters (for example, rate counters) require two values for a calculation. The
format of the buffer is assumed to be an array of PDH_RAW_COUNTER structures that contain dwNumEntries
entries.
data
A pointer to
the PDH_STATISTICS
buffer to receive the counter statistics.
Return Values
If the
function succeeds, it returns ERROR_SUCCESS. The function can return
successfully, but the returned data buffer can contain invalid data. Always
check the CStatus member of the data buffer before using the
returned statistics.
If the
function fails, the return value is a PDH error status defined in PDHMSG.H. The
following are possible error values:
PDH_INVALID_ARGUMENT
An argument
is not correct or is incorrectly formatted.
PDH_INVALID_HANDLE
The counter
handle is not valid.
See Also