Re: How to access HKEY_CURRENT_USER from local system account? - C / C++ / MFC Discussion Boards

David Crow29-Mar-06 4:43

29-Mar-06 4:43

Have you tried posing this question here, or downloading the latest version from here? Do you have access to an SMTP server?

Oliver Shikaloski wrote:
...I can only send mails that are the same type like mine.

Do you mean in your same domain?

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Message Closed

29-Mar-06 21:44

mkoliv

29-Mar-06 21:44

Message Closed

modified 28-Sep-16 7:28am.

Re: About sending mail

David Crow30-Mar-06 1:57

David Crow

30-Mar-06 1:57

oliver_mak wrote:
How do I fix this problem?

By trying my other three suggestions perhaps.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

TreeView Control Problem

gbruyneel29-Mar-06 3:00

gbruyneel

29-Mar-06 3:00

Hello
I have Visual studio 2005. I have created a Win32app project with a dialogbox containing a treeview control. As I would like to have the dialogbox in the client part of my window i have added the handle of WM_CREATE message in the MainWndProc like this :

switch (message)<br />
	{<br />
	HANDLE_MSG(hWnd, WM_CREATE,  WndProc_OnCreate);

and I have wrote :

BOOL WndProc_OnCreate(HWND hwnd,LPCREATESTRUCT ct)<br />
{<br />
    HWND g_hViewDir;<br />
    g_hViewDir = CreateDialog(hInst, MAKEINTRESOURCE(IDD_SHOWDIR), hwnd, ShowdirDlgProc);<br />
    if(g_hViewDir != NULL)<br />
    {<br />
      ...<br />
    }<br />
    else<br />
     return FALSE;<br />
return TRUE;<br />
}

No compilation error. When i launch the app the dialog does not appear. I have investigate and found that the error message comes out of the CreateDialog function and says : Error 1407 : Unknown window Class Confused | :confused:

????
Could someone help.

Re: TreeView Control Problem

Gavin Taylor29-Mar-06 3:27

Gavin Taylor

29-Mar-06 3:27

Check your linking into the Common Control library comctrl32.lib and calling InitCommonControlsEx[^] to initialize the library, finally also check your passing ICC_TREEVIEW_CLASSES as a flag so it knows to load the correct classes.

Gavin Taylor
w: http://www.gavspace.com

Re: TreeView Control Problem

gbruyneel29-Mar-06 21:23

gbruyneel

29-Mar-06 21:23

Thanks a lot that solved my problem. But in the documentation of InitCommonControlsEx it says that it is not necessary to use it if we use a manifest. In that case i do not understand.

Smile | :)

How to access HKEY_CURRENT_USER from local system account?

khb29-Mar-06 1:54

khb

29-Mar-06 1:54

Hi together,

I have a big problem. I hope somebody can help me:

I implemented a service that runs under the local system account and checks if any screen blanker is activated. I use the following code:

bool result = false;
SystemParametersInfo(SPI_GETSCREENSAVEACTIVE, 0, (LPVOID) &result, 0);

This works fine on Win XP, but on Win 2000 the function always return true. It is a known bug according to article number 318781 on MSDN.

The suggested workaround is to look for the entry "SCRNSAVE.EXE" under the registry key "HKCU\Control Panel\Desktop" using the following two lines:

RegOpenKeyEx(HKEY_CURRENT_USER, "Control Panel\\Desktop", 0, KEY_READ, &hKeyScrSave);
RegQueryValueEx(hKeyScrSave, "SCRNSAVE.EXE", NULL, NULL, (LPBYTE) szData, &dwData);

Now the problem arises: As my service runs under the local system account, access to "HKEY_CURRENT_USER" is redirected to "HKEY_USERS\.DEFAULT". Dead | X|

So the result refers to the logon screen saver, which is (usually) always activated. But I only want this result if no user in logged in.

Therefore my question: Does anybody has a solution, how to check if a screen saver is active under 2000 like SystemParametersInfo(SPI_GETSCREENSAVEACTIVE) does it for XP? An idea how to access data under "HKEY_CURRENT_USER" from the local system account would also be very valuable for me.

Thank you very much for any hints,
Marcus.

Re: How to access HKEY_CURRENT_USER from local system account?

James R. Twine29-Mar-06 2:49

James R. Twine

29-Mar-06 2:49

   Two quick things - first SystemParametersInfo(...) does not use C++ types, so you should be passing the address of a BOOL (an int, or 4-bytes under 32-bit MS), not a bool (1-byte under 32-bit MS).

   Second, I am pretty sure that screen savers run on a separate desktop, the "screen saver desktop". Search MSDN for information on Window Stations and Desktops for more information.

   If I am correct, you might be able to determine which desktop is active, and from that determine if a screen saver is running.

   Peace!

-=- James

If you think it costs a lot to do it right, just wait until you find out how much it costs to do it wrong!
Avoid driving a vehicle taller than you and remember that Professional Driver on Closed Course does not mean your Dumb Ass on a Public Road!
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Re: How to access HKEY_CURRENT_USER from local system account?

khb29-Mar-06 3:08

khb

29-Mar-06 3:08

Hi James,

thank you very much for your reply!

Concerning the bool/BOOL issue: I'm actually using a BOOL. In my message, however, I cut & pasted the code from MSDN, which seems to contain several bugs/typos Frown | :(

Anyway, thanks for the hint.

Concerning the desktop issue: I think you are right. Some time ago I've read that the screen saver runs on another desktop. So I'll dig into that again Wink | ;)

Thank you again,
Marcus.

Re: How to access HKEY_CURRENT_USER from local system account?

David Crow29-Mar-06 3:16

David Crow

29-Mar-06 3:16

khb wrote:
SystemParametersInfo(SPI_GETSCREENSAVEACTIVE, 0, (LPVOID) &result, 0);

I think you want to check SPI_GETSCREENSAVERRUNNING instead.

khb wrote:
Now the problem arises: As my service runs under the local system account, access to "HKEY_CURRENT_USER" is redirected to "HKEY_USERS\.DEFAULT".

See MSDN article Q168877 for an example.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Re: How to access HKEY_CURRENT_USER from local system account?

khb29-Mar-06 3:29

khb

29-Mar-06 3:29

Hi David,

I think that what I posted was correct. I want to check if a user has "installed" a screen saver so that I can expect that there is a change that it will start running somewhen. Anyway, I check if it is actually running, too.

The howto on Q168877 seems to be exactly what I was looking for, great!

Thank you,
Marcus.

Can I return an array of pointers of type unsigned char[]

Laughing Buddha29-Mar-06 1:52

Laughing Buddha

29-Mar-06 1:52

Hi,

I am creating an array of pointers that point to unsigned char arrays like so

unsigned char* data[3];

where
data[0] = new unsigned char[256];
data[1] = new unsigned char[256];
data[2] = new unsigned char[256];

I now want to return this pointer array data from one function. How can I do that? Or what way could I return data[0], data[1] and data[2]?

Thanks for any help cause am a bit stuck here

Re: Can I return an array of pointers of type unsigned char[]

Stephen Hewitt29-Mar-06 1:55

Stephen Hewitt

29-Mar-06 1:55

You can't return an array - If you burry it in a stuct you can work around this. i.e.

struct MyData
{
     unsigned char* data[3];
};
 
// Now return the struct instead.
MyData Function()
{
     MyData md;
     // Blah blah blah...
     return md;
}

Steve

Re: Can I return an array of pointers of type unsigned char[]

Laughing Buddha29-Mar-06 2:09

Laughing Buddha

29-Mar-06 2:09

Oh ok! Thanks.
I will call that function in a different class though. So do I have to define another struct (lets call it MyData') and then lets say

void callFunction

{
md'.data[3]=Class::Function;
...}

How would I go about getting data[0], data[1] and data[2] then? Sorry just a bit confused as its like arrays, pointers and structs and am quite new to this.

Thanks in advance for any help!

Re: Can I return an array of pointers of type unsigned char[]

Stephen Hewitt29-Mar-06 2:12

Stephen Hewitt

29-Mar-06 2:12

Code like this:

MyData d1, d2;
// Blah blah blah...
d1 = d2;

Copies dt.data[0], dt.data[1] and dt.data[2] (and all the rest if any).

Steve

Re: Can I return an array of pointers of type unsigned char[]

toxcct29-Mar-06 2:38

toxcct

29-Mar-06 2:38

you'll have to create the MyData::operator = () member for this, otherwise, it will only copy the addresses, not the array contents...

Re: Can I return an array of pointers of type unsigned char[]

Stephen Hewitt29-Mar-06 2:40

Stephen Hewitt

29-Mar-06 2:40

The question said, "return this pointer array" - I believe it's the addresses that he wants copied - Although it wasn't clearly stated.

Steve

Re: Can I return an array of pointers of type unsigned char[]

toxcct29-Mar-06 2:42

toxcct

29-Mar-06 2:42

Stephen Hewitt wrote:
Although it wasn't clearly stated

agreed

Re: Can I return an array of pointers of type unsigned char[]

toxcct29-Mar-06 2:34

toxcct

29-Mar-06 2:34

your code is incorrect because you return a local object...

>> You can't return an array
yes we can, by returning the pointer... it is exactly the same when you pass arrays as parameters to functions.

Re: Can I return an array of pointers of type unsigned char[]

Stephen Hewitt29-Mar-06 2:43

Stephen Hewitt

29-Mar-06 2:43

v2.0 wrote:
your code is incorrect because you return a local object...

No I don't - I return a copy of a local object - This is fine. Returning a pointer or reference to a local object is where you get into trouble.

v2.0 wrote:
>> You can't return an array
yes we can, by returning the pointer... it is exactly the same when you pass arrays as parameters to functions.

Returning a pointer is not the same as returning an array - A process called "decay" occurs and you lose the size info. With the code I gave (array in a struct) an array is returned and no decay occurs and the length is not lost - But the data is copied not referenced.

Steve

Re: Can I return an array of pointers of type unsigned char[]

James R. Twine29-Mar-06 2:59

James R. Twine

29-Mar-06 2:59

Stephen Hewitt wrote:
A process called "decay" occurs and you lose the size info

Not just that, but you also effectively change the type of the variable - an array is generally a valid location in memory (whose location cannot be changed easily), while a pointer can point to a valid location in memory. (This difference is also important when optimizing code.)

Peave!

-=- James

Re: Can I return an array of pointers of type unsigned char[]

Rage29-Mar-06 2:57

Rage

29-Mar-06 2:57

Since you have to put the returned array in an array anyway, you can create this "reception" array before calling the function and pass it as a parameter to the function. I think this is a much better solution than trying to "return" it, even burried in a struct. Unsure | :~