QueryInterface not returning interface

NTDEV
1

Hi,

I’m using the QueryInterface to get the interface of the IRequestCallbackCancel.

to cancel a IOrequest.

QueryInterface(__uuidof(IRequestCallbackCancel),(void**)&callback);

for some reason the callback return empty.

should i implement or register something so the interface will return valid.

as i saw the QueryInterface in CMyqueue send the request to the CUnknown.

Thanks.

2

You implement the interface, not umdf. You can tell by the name (no IWDF at the start of the name) and the remarks section on MSDN are pretty clear

Remarks

A driver registers the IRequestCallbackCancel interface when it calls the IWDFIoRequest::MarkCancelable method to enable the canceling of an I/O request. For more information about how to cancel I/O requests, see Canceling I/O Requests

http://msdn.microsoft.com/en-us/library/windows/hardware/ff556901(v=vs.85).aspx

d

debt from my phone

From: xxxxx@gmail.com
Sent: 1/11/2012 7:53 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] QueryInterface not returning interface

Hi,

I’m using the QueryInterface to get the interface of the IRequestCallbackCancel.

to cancel a IOrequest.

QueryInterface(__uuidof(IRequestCallbackCancel),(void**)&callback);

for some reason the callback return empty.

should i implement or register something so the interface will return valid.

as i saw the QueryInterface in CMyqueue send the request to the CUnknown.

Thanks.

NTDEV is sponsored by OSR

For our schedule of WDF, WDM, debugging and other seminars visit:
http://www.osr.com/seminars

To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer