Framework I/O Request Object

Warning

UMDF 2 is the latest version of UMDF and supersedes UMDF 1. All new UMDF drivers should be written using UMDF 2. No new features are being added to UMDF 1 and there is limited support for UMDF 1 on newer versions of Windows 10. Universal Windows drivers must use UMDF 2.

The archived UMDF 1 samples can be found in the Windows 11, version 22H2 - May 2022 Driver Samples Update.

For more info, see Getting Started with UMDF.

The framework I/O request object is exposed to drivers by the IWDFIoRequest interface. It encapsulates the details of an I/O operation. All I/O requests are represented as framework I/O request objects. The reflector notifies the driver host process when the reflector receives an I/O request packet (IRP) as the result of an application I/O operation, such as, a call to the Microsoft Win32 CreateFile or ReadFile function. The framework, in response to the reflector notification, constructs a new request object and puts it in the appropriate I/O queue. The queue configuration and the locking model chosen by the user-mode driver determine when the request is presented to the driver. For more information, see Configuring Dispatch Mode for an I/O Queue and Specifying a Callback Synchronization Mode.