EVT_WDF_IO_QUEUE_IO_DEFAULT callback function (wdfio.h)
[Applies to KMDF and UMDF]
A driver's EvtIoDefault event callback function processes a specified I/O request.
Syntax
EVT_WDF_IO_QUEUE_IO_DEFAULT EvtWdfIoQueueIoDefault;
void EvtWdfIoQueueIoDefault(
[in] WDFQUEUE Queue,
[in] WDFREQUEST Request
)
{...}
Parameters
[in] Queue
A handle to the framework queue object that is associated with the I/O request.
[in] Request
A handle to a framework request object.
Return value
None
Remarks
A driver registers an EvtIoDefault callback function when it calls WdfIoQueueCreate. For more information about calling WdfIoQueueCreate, see Creating I/O Queues.
If a driver has registered an EvtIoDefault callback function for a device's I/O queue, the callback function receives every I/O request from the queue, unless request-specific callback functions have also been registered. For more information about request-specific callback functions, see Request Handlers.
A driver's EvtIoDefault callback function can also receive file creation requests. For more information about receiving file creation requests, see Framework File Objects.
The EvtIoDefault callback function must process each received I/O request in some manner. For more information, see Processing I/O Requests.
Most I/O operations require an input buffer, an output buffer, or both. For information about how the driver can access a request's buffers, see Accessing Data Buffers in Framework-Based Drivers.
This callback function can be called at IRQL <= DISPATCH_LEVEL, unless the ExecutionLevel member of the device or driver's WDF_OBJECT_ATTRIBUTES structure is set to WdfExecutionLevelPassive.
If the IRQL is PASSIVE_LEVEL, the framework calls the callback function within a critical region.
For more information about IRQL levels for request handlers, see Using Automatic Synchronization.
A driver's EvtIoDefault callback function should not call the following queue object methods:
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Universal |
| Minimum KMDF version | 1.0 |
| Minimum UMDF version | 2.0 |
| Header | wdfio.h (include Wdf.h) |
| IRQL | <= DISPATCH_LEVEL (see Remarks section) |