EVT_UDECX_USB_ENDPOINT_PURGE callback function (udecxusbendpoint.h)

The USB device emulation class extension (UdeCx) invokes this callback function to stop queuing I/O requests to the endpoint's queue and cancel unprocessed requests.

Syntax

EVT_UDECX_USB_ENDPOINT_PURGE EvtUdecxUsbEndpointPurge;

void EvtUdecxUsbEndpointPurge(
  [in] UDECXUSBENDPOINT UdecxUsbEndpoint
)
{...}

Parameters

[in] UdecxUsbEndpoint

A handle to a UDE endpoint object that represents the endpoint for which I/O requests must be canceled. The client driver retrieved this pointer in the previous call to UdecxUsbEndpointCreate.

Return value

None

Remarks

The client driver registered this callback function in a previous call to UdecxUsbEndpointInitSetCallbacks by supplying a function pointer to its implementation.

In the implementation, the client driver is required to ensure all I/O forwarded from the endpoint’s queue has been completed, and that newly forwarded I/O request fail, until UdeCx invokes EVT_UDECX_USB_ENDPOINT_START. Typically, those tasks are achieved by calling WdfIoQueuePurge. This call is asynchronous and the client river must call UdecxUsbEndpointPurgeComplete.

Requirements

See also

Architecture: USB Device Emulation (UDE)

Managing I/O Queues

Write a UDE client driver