PCW_CALLBACK_TYPE enumeration (wdm.h)

The PCW_CALLBACK_TYPE enumeration defines the type of the notification sent by the system to the provider-defined PCW_CALLBACK function. The system passes a value of this enumeration in the Type parameter of the callback.

Syntax

typedef enum _PCW_CALLBACK_TYPE {
  PcwCallbackAddCounter,
  PcwCallbackRemoveCounter,
  PcwCallbackEnumerateInstances,
  PcwCallbackCollectData
} PCW_CALLBACK_TYPE, *PPCW_CALLBACK_TYPE;

Constants

PcwCallbackAddCounter The system invokes the provider's callback with this Type value to notify the provider that a consumer has added an instance filter to a query involving this counterset. Most providers will ignore notifications with this Type, but some might use this notification to optimize their data collection. For example, a provider might InterlockedIncrement a global counter for each AddCounter notification and only track performance data when the global counter is non-zero.
PcwCallbackRemoveCounter The system invokes the provider's callback with this Type value to notify the provider that a consumer has removed an instance filter from a query involving this counterset. Most providers will ignore notifications with this Type, but some might use this notification to optimize their data collection. For example, a provider might InterlockedDecrement a global counter for each RemoveCounter notification and only track performance data when the global counter is non-zero.
PcwCallbackEnumerateInstances The system invokes the provider's callback with this Type value to request the provider to provide the Name and Id values for the instances of the counterset. Most providers will use the same implementation for PcwCallbackEnumerateInstances and PcwCallbackCollectData notifications, but some might optimize data collection by skipping collection of counter data values when responding to a PcwCallbackEnumerateInstances callback.
PcwCallbackCollectData The system invokes the provider's callback with this Type value to request the provider to provide the Name, Id, and counter data values for the instances of the counterset. Refer to the documentation for the PCW_CALLBACK function for details and examples of handling this notification.

Requirements

Requirement	Value
Minimum supported client	Available in Windows 7 and later versions of Windows.
Header	wdm.h (include Wdm.h, Ntddk.h)

See also

PCW_CALLBACK callback function