PerfQueryCounterData function (perflib.h)

Article
10/13/2021

Gets the values of the performance counters that match the counter specifications in the specified query.

Syntax

ULONG PerfQueryCounterData(
  [in]            HANDLE            hQuery,
  [out, optional] PPERF_DATA_HEADER pCounterBlock,
                  DWORD             cbCounterBlock,
  [out]           LPDWORD           pcbCounterBlockActual
);

Parameters

[in] hQuery

A handle to a query for the counter specifications of the performance counters for which you want to get the values.

[out, optional] pCounterBlock

A pointer to a buffer that has enough space to receive the amount of data that the cbCounterBlock parameter specifies, in bytes. May be NULL if

cbCounterBlock is 0.

cbCounterBlock

The size of the buffer that the pCounterBlock parameter specifies, in bytes.

[out] pcbCounterBlockActual

The size of the buffer actually required to get the performance counter values. The meaning depends on the value that the function

returns.

Function Return Value	Meaning of pcbCounterBlockActual
ERROR_SUCCESS	The number of bytes of performance counter values that the function stored in the buffer that pCounterBlock specified.
ERROR_NOT_ENOUGH_MEMORY	The size of the buffer required to store the performance counter values, in bytes. Enlarge the buffer to the required size and call the function again.
Other	The value is undefined and should not be used.

Function Return Value

Meaning of pcbCounterBlockActual

ERROR_SUCCESS

The number of

bytes of performance counter values that the function stored in the buffer that pCounterBlock specified.

ERROR_NOT_ENOUGH_MEMORY

The

size of the buffer required to store the performance counter values, in bytes. Enlarge the buffer to the required

size and call the function again.

Other

The value is undefined and should not be used.

Return value

Return code	Description
ERROR_SUCCESS	The function successfully stored all of the requested performance counter values in the buffer that pCounterBlock specified. The value that pcbCounterBlockActual points to indicates amount of information actually stored in the buffer, in bytes.
ERROR_NOT_ENOUGH_MEMORY	The buffer that pCounterBlock specified was not large enough to store all of the requested performance counter values. The value that pcbCounterBlockActual points to indicates the size of the buffer required to store all of the information. Enlarge the buffer to the required size and call the function again.

For other types of failures, the return value is a system error code.

Remarks

The information about the performance counter values is written to the buffer that pCounterBlock specifies as a PERF_DATA_HEADER block, which consists PERF_DATA_HEADER structure followed by a sequence of PERF_COUNTER_HEADER blocks.

Requirements

Requirement	Value
Minimum supported client	Windows 10, version 1607 [desktop apps only]
Minimum supported server	Windows Server 2016 [desktop apps only]
Target Platform	Windows
Header	perflib.h
Library	AdvAPI32.lib
DLL	AdvAPI32.dll