WDF_MEMORY_DESCRIPTOR_INIT_HANDLE function

[Applies to KMDF and UMDF]

The WDF_MEMORY_DESCRIPTOR_INIT_HANDLE function initializes a WDF_MEMORY_DESCRIPTOR structure so that it describes a specified framework memory object.

Syntax


VOID WDF_MEMORY_DESCRIPTOR_INIT_HANDLE(
  _Out_     PWDF_MEMORY_DESCRIPTOR Descriptor,
  _In_      WDFMEMORY Memory,
  _In_opt_  PWDFMEMORY_OFFSET Offsets
);

Parameters

Descriptor [out]

A pointer to a WDF_MEMORY_DESCRIPTOR structure.

Memory [in]

A handle to a framework memory object.

Offsets [in, optional]

A pointer to a WDFMEMORY_OFFSET structure. This parameter is optional and can be NULL.

Return value

None

Remarks

The WDF_MEMORY_DESCRIPTOR_INIT_HANDLE function zeros the specified WDF_MEMORY_DESCRIPTOR structure and sets the structure's Type member to WdfMemoryDescriptorTypeHandle. Then it sets the structure's u.HandleType.Memory and u.HandleType.Offsets members to the values that the Memory and Offsets parameters specify, respectively.

Examples

The following code example obtains a handle to a framework memory object that represents an I/O request's input buffer. The example uses the memory object handle to initialize a WDF_MEMORY_DESCRIPTOR structure. Then, the example initializes a WDF_USB_CONTROL_SETUP_PACKET structure and sends a USB control transfer request to an I/O target.


WDFMEMORY  memory;
WDF_MEMORY_DESCRIPTOR  memDesc;
WDF_USB_CONTROL_SETUP_PACKET  controlSetupPacket;
NTSTATUS  status;

status = WdfRequestRetrieveInputMemory(
                                       Request,
                                       &memory
                                       );
if (!NT_SUCCESS(status)) {
    break;
}
WDF_MEMORY_DESCRIPTOR_INIT_HANDLE(
                                  &memDesc,
                                  memory,
                                  NULL
                                  );

WDF_USB_CONTROL_SETUP_PACKET_INIT_VENDOR(
                                         &controlSetupPacket,
                                         BmRequestHostToDevice,
                                         BmRequestToDevice,
                                         USBFX2LK_SET_BARGRAPH_DISPLAY,
                                         0,
                                         0
                                         );

status = WdfUsbTargetDeviceSendControlTransferSynchronously(
                                  pDevContext->UsbDevice,
                                  NULL,
                                  NULL,
                                  &controlSetupPacket,
                                  &memDesc,
                                  (PULONG)&bytesTransferred
                                  );

Requirements

Minimum KMDF version

1.0

Minimum UMDF version

2.0

Header

Wdfmemory.h (include Wdf.h)

DDI compliance rules

MemAfterReqCompletedIntIoctlA, MemAfterReqCompletedIoctlA, MemAfterReqCompletedReadA, MemAfterReqCompletedWriteA

See also

WDF_MEMORY_DESCRIPTOR
WDF_MEMORY_DESCRIPTOR_INIT_BUFFER
WDF_MEMORY_DESCRIPTOR_INIT_MDL
WDFMEMORY_OFFSET

 

 

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