Re: CString Problems - C / C++ / MFC Discussion Boards

GTS202026-Jul-04 2:28

GTS2020

26-Jul-04 2:28

Hi All,

I am spawning a process from a service. The spawned process hungs for various reasons, (corrupted data, deadlock). I am expecting the process has to complete the task with in the expected time limit, if it exceeds the limit I want to terminate the process (no mercy or graceful, just terminate the process).

The spawnng of the process, counting the time and termination of process all done in C++. Some time I am not able to terminate the process, the error message was "Access denied". I dont want this also happens. The program has to terminate the process even, the process in any state. How to do that? What security permissions I have to give?

Here is the code snippet of the teminate application,
=========================================================
static DWORD WINAPI TerminateApp( DWORD dwPID, DWORD dwTimeout )
{
HANDLE hProc ;
DWORD dwRet ;

// If we can't open the process with PROCESS_TERMINATE rights,
// then we give up immediately.
hProc = OpenProcess(SYNCHRONIZE|PROCESS_TERMINATE, FALSE,
dwPID);

if(hProc == NULL)
{
return TA_FAILED ;
}

// TerminateAppEnum() posts WM_CLOSE to all windows whose PID
// matches your process's.
EnumWindows((WNDENUMPROC)TerminateAppEnum, (LPARAM) dwPID) ;

// Wait on the handle. If it signals, great. If it times out,
// then you kill it.
if(WaitForSingleObject(hProc, dwTimeout)!=WAIT_OBJECT_0)
dwRet=(TerminateProcess(hProc,0)?TA_SUCCESS_KILL:TA_FAILED);
else
dwRet = TA_SUCCESS_CLEAN ;

CloseHandle(hProc) ;

return dwRet ;
}

static BOOL CALLBACK TerminateAppEnum( HWND hwnd, LPARAM lParam )
{
DWORD dwID ;

GetWindowThreadProcessId(hwnd, &dwID) ;

if(dwID == (DWORD)lParam)
{
PostMessage(hwnd, WM_CLOSE, 0, 0) ;
}

return TRUE ;
}

=========================================================

All suggestion appreciated.

Thanks

GTS

Re: Terminating Process

David Crow26-Jul-04 3:46

David Crow

26-Jul-04 3:46

GTS2020 wrote:
What security permissions I have to give?

MSDN indicates that the handle must have PROCESS_TERMINATE access.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/terminateprocess.asp

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Re: Terminating Process

GTS202026-Jul-04 5:20

GTS2020

26-Jul-04 5:20

Hi David thanks for your reply.

It seems the process went in to a deadlock situation. When I tried with pskill it showed "Access denied" message. I have used the following security flag "PROCESS_ALL_ACCESS" while creating the handle. Even it was not able to terminate the process.

Is there any other way to terminate the process, even whatever state it is?

Thanks

GTS

Re: Terminating Process

David Crow26-Jul-04 8:30

David Crow

26-Jul-04 8:30

GTS2020 wrote:
...the error message was "Access denied".

It's because the process you are trying to terminate is running under the Local System security account, which does not have "debugging" access. See this article for more.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Getting the HACCEL handle...

0v3rloader26-Jul-04 2:03

0v3rloader

26-Jul-04 2:03

Hello,

How do I get the handle to the accelerator table loaded by the CFrameWnd ?

The problem is I need to translate hot key messages which occur in different parts of my app (in modeless dialog boxes; in a different thread; ...), but TranslateAccelerator needs an handle to the accelerator table and I don't know how to get it -- and I'm not that keen on overriding CFrameWnd's initialitions either.

Can someone help me out here?

Thanks a lot,

David

Re: Getting the HACCEL handle...

Antony M Kancidrowski26-Jul-04 2:19

Antony M Kancidrowski

26-Jul-04 2:19

How about using LoadAccelerators()

Ant.

I'm hard, yet soft.
I'm coloured, yet clear.
I'm fruity and sweet.
I'm jelly, what am I? Muse on it further, I shall return! - David Williams (Little Britain)

CString Problems

#realJSOP26-Jul-04 0:54

#realJSOP

26-Jul-04 0:54

Compiler - VC6

I'm working on a project that is an activeX control, and that links to several DLL's. In one of the DLL's, I'm having a problem with CStrings - for some reason, I'm getting an access violation (C0000005) in MFC42D.DLL when I try to pass a CString from one class to another. Both classes are in the DLL I'm working in.

I've tried a number of methods for creating the CString in the calling function,but nothing seems to be working. Is there some sort of bizarre rule concerning CStrings that I'm not aware of?

If anyone can suggest something to check, I'd appreciate hearing about it.

------- sig starts

"I've heard some drivers saying, 'We're going too fast here...'. If you're not here to race, go the hell home - don't come here and grumble about going too fast. Why don't you tie a kerosene rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt

"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

Re: CString Problems

palbano26-Jul-04 7:33

palbano

26-Jul-04 7:33

John Simmons / outlaw programmer wrote:
Is there some sort of bizarre rule concerning CStrings that I'm not aware of?

I am aware of no such known restrictions.

John Simmons / outlaw programmer wrote:
If anyone can suggest something to check, I'd appreciate hearing about it.

Memory corruption can produce C0000005 access violation errors in blocks (objects) that are not related to the code responsible for the problem.

Is your CString object on the stack? If it is move the location significantly by placing a large block of memory on the stack right in front of it. Then test for the error again.

char buf[0xffff];
CSstring mystring;

"No matter where you go, there your are." - Buckaroo Banzai

-pete

no copy constructor?

feline_dracoform26-Jul-04 0:09

feline_dracoform

26-Jul-04 0:09

i am definitely puzzled by this.

i have a small class hierarchy:
result - abstract base class
burnsResult - abstract, derived from result
002burnsResult - concrete, derived from burnsResult
003burnsResult - concrete, derived from burnsResult
textResult - concrete, derived from result

so far so good. the default copy constructor exists for class textResult, but it does not exist for 002burnsResult or 003burnsResult.

i am getting:
error C2582: 'operator =' function is unavailable in 'file'

the VS .NET 2003 help for this error is nice and clear, the only problem is that the word operator does not exist in any of the .h files defining these classes Confused | :confused:

so how come there is a default copy constructor for one class, but not the other two?

i don't really want to define my own copy constructor, since there should be no need. i am mainly a C programmer, so perhaps i have overlooked something obvious. anyone got any ideas on why this is happening?

Re: no copy constructor?

David Crow26-Jul-04 3:53

David Crow

26-Jul-04 3:53

feline_dracoform wrote:
i am getting:
error C2582: 'operator =' function is unavailable in 'file'

On what line of code?

feline_dracoform wrote:
i don't really want to define my own copy constructor, since there should be no need.

Just because you don't see the need does not mean one does not exist. Copy constructors are almost always a good idea. At the very least, they keep the compiler from making (incorrect) assumptions.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Re: no copy constructor?

feline_dracoform27-Jul-04 2:02

feline_dracoform

27-Jul-04 2:02

DavidCrow wrote:
Copy constructors are almost always a good idea. At the very least, they keep the compiler from making (incorrect) assumptions.

i had made the assumption that using the default copy constructor was a good idea, since this made sure i wouldn't forget to copy one of the member variables of my class.

is this a bad assumption on my part?

Re: no copy constructor?

David Crow27-Jul-04 3:39

David Crow

27-Jul-04 3:39

Per MSDN:

If you do not supply any constructors, the compiler attempts to generate a default constructor. If you do not supply a copy constructor, the compiler attempts to generate one. A compiler-generated default constructor sets up the object (initializes vftables and vbtables), and it calls the default constructors for base classes and members, but it takes no other action.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Re: no copy constructor?

palbano26-Jul-04 7:53

palbano

26-Jul-04 7:53

First a copy constructor is not the same thing as an assignment operator. That said the compiler will generate a default assignment operator much the same as it does for copy constructors, i.e., member wise.

So moving on...

feline_dracoform wrote:
error C2582: 'operator =' function is unavailable in 'file'

That message does not mean that the default assignment operator has not been generated by the compiler. It is completely dependent on what you are attempting to assign to what in the code that produces that error.

Without seeing some of the pertinent code we just can't tell what the problem is.

Hate is not a family value.

-pete

Re: no copy constructor?

feline_dracoform27-Jul-04 1:12

feline_dracoform

27-Jul-04 1:12

*oops*
yes, i discovered a copy constructor isn't the same as an assignment operator after quite a bit of reading yesterday. it is a few years since i have done much C++, and i had forgotten this.

the problem function was:

result *002burnsResult::cloneResult(ParentResult *newParent)
{
    002burnsResult *newResult = new 002burnsResult;
    *newResult = *this;   // this is the problem line
    newResult->setParent(newParent);
    return newResult;
}

feeling confused, i tried to compile the same class under UNIX. this also refused to work, but the compiler told me it was unable to construct a default copy constructor for the class Confused | :confused:

i didn't even get as far as this function.

i think having a class member of type QValueVector<QString> is causing this problem, but i have no idea why. i am guessing Qt have done something strange in their classes.

writing a copy constructor, and switching to:

002burnsResult *newResult = new resultBurns(*this);<br />

works fine. the thing is, all i have done in my copy constructor is a list of a = rhs.a lines, one per class member.

at least this works, and i have re-learnt a bit of C++. i would still like to understand why this didn't work though.

disable a submenu item on runtime in an MFC app

caykahve25-Jul-04 23:35

caykahve

25-Jul-04 23:35

Hi,

To disable and enable a submenu item on runtime in an MFC app, I have used the following

code but seen no change. What is the problem with it?

MSDN says m_bAutoMenuEnable should be set to FALSE in the constructor of CMainFrame (in CMenu::EnableMenuItem), but in CDialog class there doesn't seem to be such a variable, or is there?

If I have to use ON_UPDATE_COMMAND_UI, can you give me some information on what to do?

Thanks...

// I want to disable the item "F" in the Settings Submenu, which has the ID ID_SETTINGS_F 
// File   Settings   Help
// A      B          C
// D      E    
//        F

// disable
CMenu* pMenu, *subMenu;	
pMenu = AfxGetMainWnd()->GetMenu();	
subMenu = pMenu->GetSubMenu(1);
subMenu->EnableMenuItem(ID_SETTINGS_F, MF_BYPOSITION | MF_DISABLED | MF_GRAYED);	
DrawMenuBar();
//

//enable
//...the same as above
subMenu->EnableMenuItem(ID_SETTINGS_F, MF_BYPOSITION | MF_ENABLED);
//...the same as above

Re: disable a submenu item on runtime in an MFC app

Anonymous25-Jul-04 23:45

Anonymous

25-Jul-04 23:45

i m trying to understand ur problem. if i m correct, u want to disble some submenu item on some event occuring. ur code seems to be perfectly OK. i guess u can remove the statement
DrawMenuBar();
i hope it will work. as it works in my application

Re: disable a submenu item on runtime in an MFC app

caykahve25-Jul-04 23:52

caykahve

25-Jul-04 23:52

Yes, i want to disable the submenu item on some event and enable it on some other event. However the code does not work with or without DrawMenuBar(); The menu does not get affected at all.

Should I do something with the UPDATE_COMMAND_UI?

Re: disable a submenu item on runtime in an MFC app

V.25-Jul-04 23:47

25-Jul-04 23:47

Maybe something like this:

//add event handler to menu item.

void PbmFlexListViewer::OnUpdateYourMenuItem(CCmdUI *pCmdUI){<br />
        //bool benable = true/false<br />
	pCmdUI->Enable(bEnable);<br />
}										//end function OnUpdateYourMenuItem

good luck!

"If I don't see you in this world, I'll see you in the next one... and don't be late." ~ Jimi Hendrix

Re: disable a submenu item on runtime in an MFC app

caykahve26-Jul-04 0:24

caykahve

26-Jul-04 0:24

Could not make it grayed, but is disabled right now.

I use this code and threw away the preivous things!

//to enable<br />
settingsF_Enable = TRUE;<br />
<br />
//to disable<br />
settingsF_Enable = TRUE;<br />
<br />
void MyDlg::OnUpdateSettingsF(CCmdUI* pCmdUI) <br />
{<br />
   pCmdUI->Enable(settingsF_Enable);<br />
}

I hope somebody could tell me how to make it gray. Confused | :confused:

There must be something to be added in the OnUpdateSettingsF() function, but I couldn't find how to call the pointer to the menu item and call EnableMenuItem() with MF_GRAYED

multiple text in status-bar

Anonymous25-Jul-04 23:21

Anonymous

25-Jul-04 23:21

i have created a status bar in my dialog based application.

the code is below:-

#define IDC_STATUSBAR 32000 //resource id

CStatusBarCtrl m_StatBar;

BOOL m_bStatOK = m_bStatBar.Create(WS_CHILD | WS_BORDER | WS_VISIBLE, rect, this, IDC_STATUSBAR);
m_StatBar.SetText("Application Running",0,0);

The program is running fine. the text is shoen on the left hand side of the status bar. Now i want to display another text on the right hand side of the statusbar. how do i do? i tried by inserting the statement

m_StatBar.SetText("Time",255,0);
But it had no impact?
how do i proceed? Smile | :)

Position the mouse on a web browser programmatically

yourbuddy7725-Jul-04 21:22

yourbuddy77

25-Jul-04 21:22

I want to change the position of mouse on an internet explorer window.I have tried the code below.The problem is that hr = pDoc4->createEventObject(NULL,&pEvtObj) fails.Because of this failure there is no point proceeding with the remaining code.Can you tell me the reason for this failure.Thanks in advance.

//For changing mouse position
IHTMLEventObj *pEvtObj = NULL;
IHTMLDocument4 *pDoc4 = NULL;
hr = m_pHTMLDoc->QueryInterface(IID_IHTMLDocument4,(void**)&pDoc4);//m_pHTMLDoc is a valid document pointer
if(SUCCEEDED(hr))
{
// VARIANT vEvt;
// VariantInit(&vEvt);
// vEvt.vt = VT_DISPATCH;
// vEvt.pdispVal = NULL;

hr = pDoc4->createEventObject(NULL,&pEvtObj);
if(SUCCEEDED(hr))
{
CComQIPtr<ihtmleventobj2, &iid_ihtmleventobj2=""> pEvtObj2;

pEvtObj2 = pEvtObj
Xpos = 100;
Ypos = 200;
g_Ypos = g_lastYpos = Ypos;
hr = pEvtObj2->put_clientX(Xpos);
if(hr == 0)
{
AfxMessageBox("put_clientX successful");
}
else
{
AfxMessageBox("put_clientX failed");
}
hr = pEvtObj2->put_clientY(Ypos);

// }

// pEvtObj->Release();
}
pDoc4->Release();
}

line comparison on word basis

mfc_surfer25-Jul-04 20:46

mfc_surfer

25-Jul-04 20:46

I need and algorithm or a sample code to compare two lines on word basis and show added/deleted/changed words within lines during comparison.
Any suggestion would be appreciated.

Thanks

dynamically create controls and attaching listeners to them?

misterbear25-Jul-04 20:23

misterbear

25-Jul-04 20:23

Hello, I don't know if this is super-easy to accomplish,
I am pretty new to VC++/MFC..

I need to create a dialog which must contain a different number
of CButton controls depending on certain state parameters of the
application. So I need to dynamically create a number of those
controls and attach a message handler for them ( they all share
the same message handler code ).

How do I attach this listener function to the controls once
I've created them?
(I destroy all buttons and create a bunch of new ones when the layout changes)

thankful for any help.

Re: dynamically create controls and attaching listeners to them?

KarstenK25-Jul-04 21:14

KarstenK

25-Jul-04 21:14

Why dont you enable/disable or show/hide the controls at runtime, it is also better by UI Design-Guidelines.
-> Make a full dialog with all resources in the resource editor, assign control objects to all controls and work with mycontrol.EnableWindow( bActiveNow ) Cool | :cool:

Try this @ home. (B&B)

But how to attach a message handler dynamically?

misterbear26-Jul-04 0:04

misterbear

26-Jul-04 0:04

I've thought of that as well.
But I really don't have a clue as of what the maximum number of controls is. I could of
course create a ridiculously large amount of CButton objects to be on the safe side, and just
hide/show those. But it sounds a bit unneccessary to me...

And I'm still very much interested in attaching a message handler dynamically. Can I for example
create a hook and install it for every new item? And in that hook listen for the BN_CLICKED event
and if one is received obtain the text for the control and pass it further on?

If so, how is a hook procedure attached?

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.