VHF_CONFIG structure (vhf.h)

Contains initial configuration information that is provided by the HID source driver when it calls VhfCreate to create a virtual HID device.

Syntax

typedef struct _VHF_CONFIG {

    ULONG                               Size;

    PVOID                               VhfClientContext;

    ULONG                               OperationContextSize;

#ifdef _KERNEL_MODE
    PDEVICE_OBJECT                      DeviceObject;
#else
    HANDLE                              FileHandle;
#endif

    USHORT                              VendorID;
    USHORT                              ProductID;
    USHORT                              VersionNumber;

    GUID                                ContainerID;

    USHORT                              InstanceIDLength;
    _Field_size_bytes_full_(InstanceIDLength)   
    PWSTR                               InstanceID;

    USHORT                              ReportDescriptorLength;
    _Field_size_full_(ReportDescriptorLength)
    PUCHAR                              ReportDescriptor;

    PEVT_VHF_READY_FOR_NEXT_READ_REPORT EvtVhfReadyForNextReadReport;
    PEVT_VHF_ASYNC_OPERATION            EvtVhfAsyncOperationGetFeature;
    PEVT_VHF_ASYNC_OPERATION            EvtVhfAsyncOperationSetFeature;
    PEVT_VHF_ASYNC_OPERATION            EvtVhfAsyncOperationWriteReport;
    PEVT_VHF_ASYNC_OPERATION            EvtVhfAsyncOperationGetInputReport;
    PEVT_VHF_CLEANUP                    EvtVhfCleanup;

    USHORT                              HardwareIDsLength;
    _Field_size_bytes_full_(HardwareIDsLength)
    PWSTR                               HardwareIDs;

} VHF_CONFIG, *PVHF_CONFIG;

Members

Size

Required. Size of this structure initialized by VHF_CONFIG_INIT.

VhfClientContext

Optional. An opaque pointer to HID source driver-allocated memory that the Virtual HID Framework (VHF) passes when it invokes those callback functions.

OperationContextSize

Optional. Size of the buffer that VHF must allocate for an asynchronous operation started by EvtVhfAsyncOperation. If non-zero, VHF allocates a buffer of this size and passes a pointer to that buffer in the VhfOperationContext parameter each time it invokes EvtVhfAsyncOperation to start a new operation.

DeviceObject

Required for kernel-mode drivers. A pointer to the DEVICE_OBJECT structure for the HID source driver. Get that pointer by calling WdfDeviceWdmGetDeviceObject and passing the WDFDEVICE handle that the driver received in the WdfDeviceCreate call.

FileHandle

Required for user-mode drivers. A file handle obtained by calling WdfIoTargetWdmGetTargetFileHandle. To open a WDFIOTARGET, a user-mode (UMDF) VHF source driver should call WdfIoTargetOpen with OpenParams.Type set to WdfIoTargetOpenLocalTargetByFile.

VendorID

Optional. Vendor ID of the virtual HID device to be created.

ProductID

Optional. Product ID of the virtual HID device to be created.

VersionNumber

Optional. Version number of the virtual HID device to be created.

ContainerID

Optional. Container ID of the virtual HID device to be created.

InstanceIDLength

InstanceID

ReportDescriptorLength

Required. The length of the HID Report Descriptor contained in a buffer pointed by ReportDescriptor.

ReportDescriptor

Required. A pointer to a HID source driver-allocated buffer that contains the HID Report Descriptor.

EvtVhfReadyForNextReadReport

Optional. A pointer to an EvtVhfReadyForNextReadReport callback. The HID source driver must implement and register this callback function if it wants to handle the buffering policy for submitting HID Input Reports. If this callback is specified, VHF does not buffer those reports. The HID source driver should submit one report by calling VhfReadReportSubmit, each time VHF invokes EvtVhfReadyForNextReadReport.

EvtVhfAsyncOperationGetFeature

Optional. A pointer to an EvtVhfAsyncOperation callback. The HID source driver must implement and register this callback function if it wants to a get a HID Feature Report associated with a Top-Level Collection from the HID class driver pair. The driver can get a Feature Report only if the Report Descriptor declares it.

EvtVhfAsyncOperationSetFeature

Optional. A pointer to an EvtVhfAsyncOperation callback. The HID source driver must implement and register this callback function if it wants to a send a HID Feature Report associated with a Top-Level Collection to the HID class driver pair. The driver can set a Feature Report only if the Report Descriptor declares it.

EvtVhfAsyncOperationWriteReport

Optional. A pointer to an EvtVhfAsyncOperation callback. The HID source driver must implement and register this callback function if it wants to a support HID Output Reports and send them to the HID class driver pair.

EvtVhfAsyncOperationGetInputReport

Optional. A pointer to an EvtVhfAsyncOperation callback. The HID source driver must implement and register this callback function if it wants to support on-demand query for Input Reports.

EvtVhfCleanup

Optional. A pointer to a EvtVhfCleanup callback. The HID source driver can implement and register this callback function if it wants to free the allocated resources for the virtual HID device.

HardwareIDsLength

HardwareIDs

Requirements

Requirement	Value
Minimum supported client	Windows 10
Minimum supported server	None supported
Header	vhf.h

See also

Write a HID source driver by using Virtual HID Framework (VHF)