_WDF_REQUEST_COMPLETION_PARAMS structure

[Applies to KMDF and UMDF]

The WDF_REQUEST_COMPLETION_PARAMS structure contains parameters that are associated with the completion of an I/O request.

Syntax

typedef struct _WDF_REQUEST_COMPLETION_PARAMS {
  ULONG            Size;
  WDF_REQUEST_TYPE Type;
  IO_STATUS_BLOCK  IoStatus;
  union {
    struct {
      WDFMEMORY Buffer;
      size_t    Length;
      size_t    Offset;
    } Write;
    struct {
      WDFMEMORY Buffer;
      size_t    Length;
      size_t    Offset;
    } Read;
    struct {
      ULONG  IoControlCode;
      struct {
        WDFMEMORY Buffer;
        size_t    Offset;
      } Input;
      struct {
        WDFMEMORY Buffer;
        size_t    Offset;
        size_t    Length;
      } Output;
    } Ioctl;
    struct {
      union {
        PVOID     Ptr;
        ULONG_PTR Value;
      } Argument1;
      union {
        PVOID     Ptr;
        ULONG_PTR Value;
      } Argument2;
      union {
        PVOID     Ptr;
        ULONG_PTR Value;
      } Argument3;
      union {
        PVOID     Ptr;
        ULONG_PTR Value;
      } Argument4;
    } Others;
    struct {
      PWDF_USB_REQUEST_COMPLETION_PARAMS Completion;
    } Usb;
  } Parameters;
} WDF_REQUEST_COMPLETION_PARAMS, *PWDF_REQUEST_COMPLETION_PARAMS;

Members

IoStatus

An IO_STATUS_BLOCK structure for the request.

Parameters

Request-specific values for the request.

Size

The size, in bytes, of this structure.

Type

A WDF_REQUEST_TYPE value that identifies the request type.

Remarks

The WDF_REQUEST_COMPLETION_PARAMS structure is used as input to the WdfRequestGetCompletionParams method and a driver's CompletionRoutine callback function.

In both cases, the completion parameters structure contains valid information only if the driver has formatted the request by calling one of the WdfIoTargetFormatXxx methods. For example, see WdfIoTargetFormatRequestForRead.

Before calling WdfRequestGetCompletionParams to retrieve the I/O completion information for a request, the driver must first call WDF_REQUEST_COMPLETION_PARAMS_INIT to initialize the WDF_REQUEST_COMPLETION_PARAMS structure.

The Parameters.Others.Argument members are custom arguments that a driver typically passes down the stack (and can arrive back after the request is completed). They are used for non-standard, driver stack dependent data. For example, a USB driver specifies a pointer to a URB in Parameters.Others.Argument1 when it sends a IOCTL_INTERNAL_USB_SUBMIT_URB request to the USB stack. Similarly, a Bluetooth driver specifies a pointer to a BRB (Bluetooth Request Block) in Parameters.Others.Argument1 when it receives an IOCTL_INTERNAL_BTH_SUBMIT_BRB.

Requirements

   
Minimum KMDF version 1.0
Minimum UMDF version 2.0
Header wdfrequest.h (include Wdf.h)

See Also

CompletionRoutine

WdfRequestGetCompletionParams

IO_STATUS_BLOCK

WDF_REQUEST_TYPE

WDF_REQUEST_COMPLETION_PARAMS_INIT

Send comments about this topic to Microsoft