WDF_REQUEST_COMPLETION_PARAMS structure (wdfrequest.h)
[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
Size
The size, in bytes, of this structure.
Type
A WDF_REQUEST_TYPE value that identifies the request type.
IoStatus
An IO_STATUS_BLOCK structure for the request.
Parameters
Request-specific values for the request.
Parameters.Write
Parameters.Write.Buffer
A handle to a framework memory object. This object identifies the buffer that the driver specified when it formatted the request and sent it to an I/O target.
Parameters.Write.Length
Length, in bytes, of the transfer.
Parameters.Write.Offset
Beginning address within the buffer for the data transfer.
Parameters.Read
Parameters.Read.Buffer
A handle to a framework memory object. This object identifies the buffer that the driver specified when it formatted the request and sent it to an I/O target.
Parameters.Read.Length
Length, in bytes, of the transfer.
Parameters.Read.Offset
Beginning address within the buffer for the data transfer.
Parameters.Ioctl
Parameters.Ioctl.IoControlCode
Parameters.Ioctl.Input
Parameters.Ioctl.Input.Buffer
A handle to a framework memory object. This object identifies the input buffer that the driver specified when it formatted the request and sent it to an I/O target.
Parameters.Ioctl.Input.Offset
Beginning address within the buffer for the data transfer.
Parameters.Ioctl.Output
Parameters.Ioctl.Output.Buffer
A handle to a framework memory object. This object identifies the output buffers that the driver specified when it formatted the request and sent it to an I/O target.
Parameters.Ioctl.Output.Offset
Beginning address within the buffer for the data transfer.
Parameters.Ioctl.Output.Length
Length, in bytes, of the transfer.
Parameters.Others
Parameters.Others.Argument1
Use of this member is defined by the driver stack. See Remarks.
Parameters.Others.Argument1.Ptr
Parameters.Others.Argument1.Value
Parameters.Others.Argument2
Use of this member is defined by the driver stack.
Parameters.Others.Argument2.Ptr
Parameters.Others.Argument2.Value
Parameters.Others.Argument3
Use of this member is defined by the driver stack.
Parameters.Others.Argument3.Ptr
Parameters.Others.Argument3.Value
Parameters.Others.Argument4
Use of this member is defined by the driver stack.
Parameters.Others.Argument4.Ptr
Parameters.Others.Argument4.Value
Parameters.Usb
For USB devices, this member contains a pointer to a WDF_USB_REQUEST_COMPLETION_PARAMS structure.
Parameters.Usb.Completion
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
| Requirement | Value |
|---|---|
| Minimum KMDF version | 1.0 |
| Minimum UMDF version | 2.0 |
| Header | wdfrequest.h (include Wdf.h) |