C / C++ / MFC

DMA access from user-mode

23-Mar-09 2:47

In release mode no variable is initialized by default, that could change the context between release & debug modes. Anyway can you post the full function code here?

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Maxwell Chen22-Mar-09 21:58

22-Mar-09 21:58

Is it possible to access DMA from the user-mode (driver or application)? If yes, what are the APIs provided by Windows? Thanks.

Maxwell Chen

Iain Clarke, Warrior Programmer

Iain Clarke, Warrior Programmer22-Mar-09 23:35

22-Mar-09 23:35

I can give you a 99% confident answer of NO.

You can't access IRQs, or even "real" memory, both of which you'd need for DMA.

This is the job of kernel mode drivers, and they're a whole nasty territory. I have written a couple, and debugging was a PAIN! Never did get the hang of debugging them, and it (used to be) serial only for a remote computers.

Good luck,

Iain.

In the process of moving to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), give me a job!

Maxwell Chen23-Mar-09 3:58

23-Mar-09 3:58

Thanks!

Maxwell Chen

Eytukan23-Mar-09 0:41

23-Mar-09 0:41

Holy sh*t! Just noticing the name. When are you back? I thought you were dead. May be you have the right to think the same on me. I'm back after 2 years. Cool | :cool:

. So how's life? Big Grin | :-D

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

CPallini23-Mar-09 1:32

CPallini

23-Mar-09 1:32

Uhm... Pardon the intrusion... But I see a THHB's action in progress here... Big Grin | :-D

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Eytukan23-Mar-09 2:48

23-Mar-09 2:48

Oh come in Pallini Smile | :)

no probs. Yeah I just figured it out he's been farting around for a while.. Smile | :)

but see it looks like he's back to his cave again.

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Maxwell Chen23-Mar-09 4:13

23-Mar-09 4:13

The cave[^] is fun! Big Grin | :-D

But my cell phone was not capable enough to handle that nearly complete dark though. Big Grin | :-D

Maxwell Chen

Maxwell Chen23-Mar-09 4:09

23-Mar-09 4:09

I come back only when I have questions ... Poke tongue | ;-P

Actually I got laid off last October, and then started my new job by the end of last year. Programming the audio stuffs is completely new to me. I've been quite busy getting myself familiar with everything of this job these days. Big Grin | :-D

Maxwell Chen

Eytukan23-Mar-09 4:52

23-Mar-09 4:52

Can you mail me your personal id? I'm sure you aren't using the old one. the h*tmail id

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Maxwell Chen23-Mar-09 4:56

23-Mar-09 4:56

I've never had any hotmail id... Unsure | :~

Maxwell Chen

Eytukan23-Mar-09 17:56

23-Mar-09 17:56

Sorry the yahoo. S*****r@yahoo.com

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Maxwell Chen23-Mar-09 18:30

23-Mar-09 18:30

That's for hot girls. Laugh | :laugh:

Maxwell Chen

Eytukan23-Mar-09 18:33

23-Mar-09 18:33

Sh*t! Okay anyway it looks like you are not using the id anymore and hence no girls are near you anymore. Jig | [Dance]

looser

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Maxwell Chen23-Mar-09 19:33

problem facing in updating images dynamically at runtime using IWebBrwoser2 and IHTMLElement in custom browser

23-Mar-09 19:33

$Shucks | :-\$ Poke tongue | ;-P

Maxwell Chen

Abhijit A22-Mar-09 21:39

Abhijit A

22-Mar-09 21:39

Hello friend,

I need to show one small "Please Wait.." image screen whenewer some back end processing is in progress.
For e.g. whenever user changing his ip adress and port, before going checking and establishing the connection, I want to show a "Please wait ..." image.But while going for connection browser gets hangs because of connection and after connection checking is completed. It goes for next page.

I am using IWebBrowser2 interface through which, I am getting pointer of browser.Then I am using IHTMLELement through which I am getting pointer of current html content.After that I am using IHTMLImageElement to add one img tag inside current html page for please wait screen.

Please give me some suggestions.
Waiting for the positive reply

Thank you.

abhi

SHFILEOPSTRUCT in unicode [modified]

p_196022-Mar-09 20:40

p_1960

22-Mar-09 20:40

Hi,

When im using the below code

SHFILEOPSTRUCTW sh;

sh.hwnd = GetSafeHwnd();
sh.wFunc = FO_DELETE;
sh.pFrom = L"C:\\Documents and Settings\\Myid\\Local Settings\\Temp\\Tester";
sh.pTo = NULL;
sh.fFlags = FOF_NOCONFIRMATION | FOF_SILENT;
sh.hNameMappings = 0;
sh.lpszProgressTitle = NULL;

SHFileOperationW (&sh);

im getting the error...
cannot delete file:Cannot read from the source file or disk...

and when im using the SHFILEOPSTRUCTA it is deleting.... can u plesase tell me what"s the difference in these two ....(SHFILEOPSTRUCTW and SHFILEOPSTRUCTW)...and i have to use unicode only.....

modified on Monday, March 23, 2009 4:23 AM

Jijo.Raj22-Mar-09 20:53

Jijo.Raj

22-Mar-09 20:53

p_1960 wrote:
and when im using the SHFILEOPSTRUCTA it is deleting.... can u plesase tell me what"s the difference in these two ....(SHFILEOPSTRUCTW and SHFILEOPSTRUCTW)...and i have to use unicode only.....

both are same.

Well, Why do you choose unicode or Ansi version by yourself? just use SHFILEOPSTRUCT + SHFileOperation() and enclose strings in _T() macro. So that the unicode or ansi version will be selected automatically. For instance,

SHFILEOPSTRUCT sh;

sh.hwnd = GetSafeHwnd();
sh.wFunc = FO_DELETE;
sh.pFrom = _T( "C:\\Documents and Settings\\ICS400758\\Local Settings\\Temp\\Tester");
sh.pTo = NULL;
sh.fFlags = FOF_NOCONFIRMATION | FOF_SILENT;
sh.hNameMappings = 0;
sh.lpszProgressTitle = NULL;

SHFileOperation (&sh);

Regards,
Jijo.

_____________________________________________________

http://weseetips.com[^] Visual C++ tips and tricks. Updated daily.

p_196022-Mar-09 22:07

p_1960

22-Mar-09 22:07

Thanks for ur reply.....

Even i used the code which u gave im getting the same error

cannot delete file:Cannot read from the source file or disk...

Please help me out...

Re: SHFILEOPSTRUCT in unicode [modified]

CPallini22-Mar-09 22:14

CPallini

22-Mar-09 22:14

Please show us the code that is working.
Smile | :)

Iain Clarke, Warrior Programmer22-Mar-09 23:45

Iain Clarke, Warrior Programmer

22-Mar-09 23:45

I think I may have found your issue...

MSDN wrote:
pFrom
Address of a buffer to specify one or more source file names. These names must be fully qualified paths. Standard DOS wild cards, such as "*", are permitted in the file-name position. Although this member is declared as a null-terminated string, it is used as a buffer to hold multiple file names. Each file name must be terminated by a single NULL character. An additional NULL character must be appended to the end of the final name to indicate the end of pFrom.

You don't give an additional NULL, so the shell operation carries on looking for the next string... which will be gobbledegook at best. I think the compiler is adding padding, which is why the next character stands a better chance of being NULL in the ansi version then the unicode version. This theory is very handwavy and untested, but you are not following the manual either way.

So, try:

sh.pFrom = T("C:\\Documents and Settings\\Myid\\Local Settings\\Temp\\Tester\0"); // Give it an extra NULL.

Less importantly, I'd write

sh.hNameMappings = NULL;

MSDN wrote:
...Treat hNameMappings as a pointer to a structure...

It's the same thing really, but it will help you in a years time and you come back to read the code...

Hope that helped,

Iain.

In the process of moving to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), give me a job!

modified on Monday, March 23, 2009 5:57 AM

p_196023-Mar-09 0:05

p_1960

23-Mar-09 0:05

sh.hwnd =GetSafeHwnd();

Please let me know What exactly the above line of code indicates...