IWDFIoRequest::GetWriteParameters method (wudfddi.h)

The GetWriteParameters method retrieves the request parameters for a write-type request.

Syntax

void GetWriteParameters(
  [out, optional] SIZE_T   *pSizeInBytes,
  [out, optional] LONGLONG *pullOffset,
  [out, optional] ULONG    *pulKey
);

Parameters

[out, optional] pSizeInBytes

A pointer to a variable that receives the size, in bytes, to write. To retrieve the data for writing, the driver calls the IWDFIoRequest::GetInputMemory method.

This parameter is optional. The driver can pass NULL if it does not require the information.

[out, optional] pullOffset

A pointer to a variable that receives the offset, in bytes, to begin writing to the device or the file on the device. If the device does not support absolute write addresses, pullOffset can be ignored. For more information, see the following Remarks section.

Client applications specify this value in the Offset and OffsetHigh members of the OVERLAPPED structure. A pointer to OVERLAPPED is passed in the Microsoft Win32 WriteFile or WriteFileEx function.

This parameter is optional. The driver can pass NULL if it does not require the information.

[out, optional] pulKey

A pointer to a variable that receives a key that the driver can use to sort the I/O request in a way that the driver determines.

This parameter is optional. The driver can pass NULL if it does not require the information.

Return value

None

Remarks

A call to GetWriteParameters fails if the request type is not a write type.

For devices that support addressing (for example, a disk device), the value that the pullOffset parameter points to is typically the byte offset into the device. For devices that do not support addressing (for example, a serial port), the driver can ignore the value at pullOffset.

Requirements

See also

• IWDFIoRequest
• IWDFIoRequest::GetInputMemory