Re: OVERLAPPED IO

what he means is that you supply the overlapped structure w/the event and after sending the i/o you just wait infinitely on the event right after the call.

d

--
Please do not send e-mail directly to this alias. this alias is for
newsgroup purposes only.
This posting is provided "AS IS" with no warranties, and confers no rights.


"kota" <kota@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message news:8A439FB2-D186-42F4-ACEB-592E8D64407E@xxxxxxxxxxxxxxxx
Hi Roberts,

Could you explain, "it's not that hard to "simulate" a non-overlapped call
on an overlapped> handle".

Do i have to have two different handles, one for overlapped structures &
other for non ovl structures?

Thanks,
Prafulla

"Tim Roberts" wrote:

May <May@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
>I call DeviceIoControl with overlapped flag set FILE_FLAG_OVERLAPPED in
>createFile,
>1. Do I need to do other open device (device ready opened for
>DeviceIoControl for other functions) for this overlapped IO?

I don't understand what you are asking. As long as you called CreateFile
with FILE_FLAG_OVERLAPPEED, you can do as many DeviceIoControl calls as you
want. You can certainly have another handle open for non-overlapped calls,
it's not that hard to "simulate" a non-overlapped call on an overlapped
handle

>2. I did tried to call open device again, then call overlapped
>DeviceIoControl, I got return 0, but GetLastError() return is 0 -- >ERROR_SUCCESS? What dose it means? success or not?

That is unexpected. Why don't you show us the code? We'll see what looks
funny.

>3. When should I close the device for this overlapped DeviceIoControl >call,
>close immidiately after return or wait until IO complete?

The close won't happen until the I/O is completed, but I would certainly
want to wait.

>4. In my driver, I forward this IO to a waitqueue and return pending >(not
>complete), is it correct?

Probably, but it is mostly irrelevant to the discussion of overlapped I/O
in user mode.
--
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.


.

Relevant Pages