EVT_WDF_CHILD_LIST_IDENTIFICATION_DESCRIPTION_CLEANUP callback function (wdfchildlist.h)

Article
02/22/2024

[Applies to KMDF only]

A driver's EvtChildListIdentificationDescriptionCleanup event callback function frees any memory allocations for an identification description that the driver's EvtChildListIdentificationDescriptionDuplicate callback function allocated.

Syntax

EVT_WDF_CHILD_LIST_IDENTIFICATION_DESCRIPTION_CLEANUP EvtWdfChildListIdentificationDescriptionCleanup;

void EvtWdfChildListIdentificationDescriptionCleanup(
  [in]      WDFCHILDLIST ChildList,
  [in, out] PWDF_CHILD_IDENTIFICATION_DESCRIPTION_HEADER IdentificationDescription
)
{...}

Parameters

[in] ChildList

A handle to a framework child-list object.

[in, out] IdentificationDescription

A pointer to a WDF_CHILD_IDENTIFICATION_DESCRIPTION_HEADER structure that identifies an identification description.

Return value

None

Remarks

If a bus driver is using dynamic enumeration, it can register an EvtChildListIdentificationDescriptionCleanup callback function by calling WdfFdoInitSetDefaultChildListConfig or WdfChildListCreate.

If an identification description points to additional information that is stored in dynamically allocated memory, and if that memory is allocated by an EvtChildListIdentificationDescriptionDuplicate callback function, the driver must provide an EvtChildListIdentificationDescriptionCleanup callback function.

Typically, the EvtChildListIdentificationDescriptionDuplicate callback function allocates memory by calling ExAllocatePool. The EvtChildListIdentificationDescriptionCleanup callback function must deallocate that memory by calling ExFreePool. This callback function must not attempt to deallocate the rest of the identification description. In other words, the callback function must not deallocate the address description structure that the IdentificationDescription parameter points to; it must deallocate only additional memory allocations that the description structure points to.

For more information about dynamic enumeration, see Enumerating the Devices on a Bus.

Requirements

Requirement	Value
Target Platform	Universal
Minimum KMDF version	1.0
Header	wdfchildlist.h (include Wdf.h)
IRQL	<= DISPATCH_LEVEL