C / C++ / MFC Discussion Boards

Member 36807856-Nov-09 5:50

6-Nov-09 5:50

I have been trying to correct an assertion failure in an MFC app for the last few days. It's been really fun... while the rest of you have been doing boring things like riding your outlandish motorcycles or bar-hopping with your chubby girlfriends, I get to really spend some quality time trying to comprehend things like "___Afx_4_U_T_q_HowDoesThisEvenCompile_<t>".

Anyhoo... an assertion fails somewhere in Wincore.cpp (a local called pMap comes up as 0, implying a call from the wrong thread, I am thinking). When the failure occurs, Visual Studio breaks into Wincore.cpp (which it finds and opens) and does a good job of debugging. It shows a call stack, "Watch" and "Quickwatch" seem to work, etc.

The problem arises when I try to do some manual editing to Wincore.cpp, or even just set a breakpoint in Wincore.cpp. It quickly becomes obvious that even though Visual Studio itself found and opened this file just a moment ago, it is not actually using the copy of Wincore.cpp that I am seeing as part of the build process. So, I can make garbage edits to it, do a "Rebuild All," and still get no errors. This seems completely wrong to me and provokes my ire at a very fundamental level. I mean, I guess Microsoft and I have different definitions of terms like "compile" and "source code."

When I try to simply set a breakpoint in Wincore.cpp without changing it, the breakpoint's red dot indicator goes "hollow" at runtime. When I hover over the breakpoint, Visual Studio tells me that the source code is different from that used in compilation. If I check "allow location to be different" in the breakpoint properties, then the breakpoint gets hit, but Visual Studio claims to have no source code. It prompts me to browse to the original source code. Strangely, there is a text field in this dialog showing where the source code originally resided, and this is some path on F:-drive (which, in my case, is a removable flash drive that isn't even present in the system).

I'm not sure how much more "original" I can get than the file I'm TRYING to use, which is in a subfolder of C:\Program Files\Microsoft Visual Studio 2008\ and was opened up for me by Visual Studio. Am I expected to e-mail Raymond Chen for the copy on his hard drive perhaps?

Generally, I don't need to edit Wincore.cpp; I would never do this permanently. Also, I suppose I haven't had much experience setting breakpoints in that file. However, I think that what I am trying to do should be possible, and I think that Visual Studio's behavior is very misleading. Am I or am I not building a file called Wincore.cpp into my project? The IDE really seems to want to have it both ways.

Perhaps I simply have something configured wrong?

Are "precompiled headers" causing the problem? (I don't think so, since Wincore.cpp is not really a "header" file; BUT, in my miserable experience with Visual C++, "precompiled headers" are one of Microsoft's most popular implements of torture. )

Also, if anyone has some different advice about how I ought to find the problem, that's very welcome too. I don't give a flip about Wincore.cpp or understanding it. I just want to fix my problem.

Re: Breakpoints in Wincore.cpp

Rajesh R Subramanian6-Nov-09 6:26

Rajesh R Subramanian

6-Nov-09 6:26

I see you're using VS 2008.

I know that when an MFC application initialises, the function AfxGetThread() in thrdcore.cpp will be called. I was able to set a breakpoint on that function, without even opening the file. I chose Debug->New BreakPoint->Break at function-> enter function name as AfxGetThread() and set line and character as 1 each.

When I hit F5, the debugger opened thrdcore.cpp and broke at the beginning of AfxGetThread(). You might want to try it with the function of your interest located in wincore.cpp. The IDE will open the correct file (that it is using), and break at the location of your interest.

You might as well consider using "Advanced breakpoints" (just do a search). Smile | :)

“Follow your bliss.” – Joseph Campbell

Re: Breakpoints in Wincore.cpp

sashoalm6-Nov-09 6:32

sashoalm

6-Nov-09 6:32

Member 3680785 wrote:
It quickly becomes obvious that even though Visual Studio itself found and opened this file just a moment ago, it is not actually using the copy of Wincore.cpp that I am seeing as part of the build process. So, I can make garbage edits to it, do a "Rebuild All," and still get no errors. This seems completely wrong to me and provokes my ire at a very fundamental level. I mean, I guess Microsoft and I have different definitions of terms like "compile" and "source code."

I think that wincore.cpp is provided for debugging purposes only, MFC can't be compiled easily from the source. What your app links to is the debug versions of MFC dlls. As for VS finding the source that's probably because it is referenced in the dll or some pch file or some such.

There is sufficient light for those who desire to see, and there is sufficient darkness for those of a contrary disposition.
Blaise Pascal

Re: Breakpoints in Wincore.cpp

Randor 6-Nov-09 7:15

Randor

6-Nov-09 7:15

Hi,

I just wanted to add some observations. You state in your ~~message~~ novel that the variable pMap is NULL. I recognize this variable name as possibly being the internel MFC CHandleMap. If this variable is NULL then you are incorrectly accessing MFC objects across a thread boundry.

I would suggest that you research the following:

Description of CWnd derived MFC objects and multithreaded applications in Visual C++[^]

Inside MFC: Handle Maps and Temporary Objects[^]

Best Wishes,
-David Delaune

CDatabase::OpenEx failure kills UI thread

Gary Wheeler6-Nov-09 5:13

Gary Wheeler

6-Nov-09 5:13

I've recently moved my data base code into a worker thread, which works just fine unless the data base open fails. I currently have the thread wait 15 seconds, and then try the open again. This process repeats until the data base opens successfully or the application exits. The problem I'm having is that, when this logic is occurring, my UI thread will fail with an access violation some time later. It appears that having the CDatabase::OpenEx() call fail causes some sort of corruption to either the UI thread's MFC state or its stack, which is then exposed as the UI is navigated.

I'm using SQL Server 2005 Express, Service Pack 2.

I've tried the following to resolve this:

1. If I comment out the data base operations (OpenEx() ... Close()), the UI does not crash.

2. If I comment out the data base operations like in #1, and replace them with a AfxThrowDBException(...), the UI does not crash.

3. One suspect was the CDatabase::OpenEx() implementation, which does some hinky looking things trying to find a window handle. I overrode it and passed a NULL window handle to the ::SQLDriverConnect() call that does the real work of connecting to the data base. The UI still crashes.

From these results I can only conclude that there is some kind of problem here using CDatabase/CRecordset in a worker thread that isn't documented. I've searched on MSDN and Google'd several times, and only found claims of issues with specific ODBC drivers.

Anyone have any suggestions, or ideas that I've missed?

Software Zen: delete this;

Re: CDatabase::OpenEx failure kills UI thread

Randor 6-Nov-09 6:25

Randor

6-Nov-09 6:25

Hi Gary,

Are your CDatabase functions inside your application executable or are you calling them from a helper DLL? Are you static or dynamic linking?

Does the error occur if you add the following before attempting to use CDatabase::OpenEx:

AFX_MANAGE_STATE(AfxGetStaticModuleState());[^]

Best Wishes,
-David Delaune

Re: CDatabase::OpenEx failure kills UI thread

Gary Wheeler6-Nov-09 8:35

Gary Wheeler

6-Nov-09 8:35

The CDatabase functions are inside my application executable, and MFC is dynamically linked.

I tried using your AFX_MANAGE_STATE() suggestion, but it had no effect.

Thanks for the help Rose | [Rose]

Software Zen: delete this;

Running task on shutdown

__DanC__6-Nov-09 2:29

__DanC__

6-Nov-09 2:29

Hi,

Apologies if this has been covered somewhere but I've not found anything related. I'm working on an idea which would require a long-running task to complete at the time the user logs off, I know it's possible to delay the logoff but I was hoping to find a way to run the task as part of the logoff, something like when Windows synchronises offline folders (not sure if that's exactly the right term as I am working from memory here).

Does anyone have any ideas?

Thanks

Re: Running task on shutdown

Randor 6-Nov-09 6:08

Randor

6-Nov-09 6:08

Hi,

You failed to mention what type of application you are developing. Assuming that you have a usermode application I would recommend returning FALSE to the WM_QUERYENDSESSION message[^].

However if you are developing a windows service; Here is a previous thread which covers the topic:

http://www.codeproject.com/Messages/3244431/Re-Delaying-Shutdown-through-windows-service-and-e.aspx[^]

Best Wishes,
-David Delaune

Re: Running task on shutdown

Rajesh R Subramanian6-Nov-09 6:09

Rajesh R Subramanian

6-Nov-09 6:09

*click*

Good Answer. Smile | :)

“Follow your bliss.” – Joseph Campbell

Re: Running task on shutdown

__DanC__6-Nov-09 6:18

__DanC__

6-Nov-09 6:18

Thanks for the reply, it is a user mode application and I know I can prevent shutdown by returning false for WM_QUERYENDSESSION but that keeps the logged in session alive, what I want to do is to run the code during the logoff, effectively after the user has been logged off.

For example, when you a running Windows XP on a domain and you have offline file enabled, you will see the synchronisation window appear during the logoff to sync any remaining files back to the domain controller, I'm trying to achieve something like this. The app does not have to remain a user mode app, it could quite easily become a service if that is required but preventing the logoff is not what I'm trying to achieve.

Thanks.

Re: Running task on shutdown

Randor 6-Nov-09 6:51

Randor

6-Nov-09 6:51

__DanC__ wrote:
Thanks for the reply, it is a user mode application

Usermode applications are limited in their ability to delay/prevent shutdown. You are basically limited to what I described in my previous posts. I believe that you have 5 seconds to respond to the WM_QUERYENDSESSION so you might be able to perform some last-second tasks.

__DanC__ wrote:
For example, when you a running Windows XP on a domain and you have offline file enabled, you will see the synchronisation window appear during the logoff to sync any remaining files back to the domain controller, I'm trying to achieve something like this.

Have you considered using Logon/Logoff[^] or Startup/Shutdown[^] scripts? This is typically what an administrator would use to execute something on shutdown/logoff.

Best Wishes,
-David Delaune

Re: Running task on shutdown

__DanC__6-Nov-09 6:53

__DanC__

6-Nov-09 6:53

Thanks for the tip, I'll have a look into the scripts and see if they can do what I need. I've just discovered SCM notifications which look promising although I haven't read enough about them to know if they can do what I want yet.

Re: Running task on shutdown

Randor 6-Nov-09 7:07

Randor

6-Nov-09 7:07

__DanC__ wrote:
I've just discovered SCM notifications which look promising

Yeah, you will have some additional time I think... 20 seconds when you handle the SERVICE_CONTROL_SHUTDOWN message. You can keep posting STOP_PENDING to the SCM for some additional time.

Best Wishes,
-David Delaune

Create Split Window in RightView of SDI

Abinash Mohanty5-Nov-09 23:16

Abinash Mohanty

5-Nov-09 23:16

Hi,

I have created a SDI application with having a LeftView and RightView.LeftView is inherited from CTreeCtrl class where as the rightview is inherited from CFormView class.Can anybody tell me how to split the rightview into 2 halves?

Thanks,
Abinash

Re: Create Split Window in RightView of SDI

Adam Roderick J5-Nov-09 23:22

Adam Roderick J

5-Nov-09 23:22

Just refer this article
it will easy for you to understand Extended Splitter Window class[^]

Величие не Бога может быть недооценена.

Re: Create Split Window in RightView of SDI

jinlsg8-Nov-09 14:15

jinlsg

8-Nov-09 14:15

You may be inherit yourself CMySplitterWnd inherited from CSplitterWnd.

where is my fault?

goutom roy5-Nov-09 23:10

goutom roy

5-Nov-09 23:10

**************************************
//#include "simple calculator.h" ->code
class CExerciseApp : public CWinApp
{
public:
virtual BOOL InitInstance();
};

class CMainFrame : public CFrameWnd
{
//CString s = _T("1032");
//int n = ParseInt( s );

public:
CButton b1, b2, b3, b4, b5;
CEdit text1, text2, res;
CString str1, str2;
//CFont font;
long a, b, c;

CMainFrame();

void addition();
void substruction();
void production();
void dividation();
void modulation();

DECLARE_MESSAGE_MAP()
};
*******************************
#include <afxwin.h>
#include <string.h>
#include <windows.h>
#include <math.h>
#include "simple calculator.h"

#define plus 11
#define minus 12
#define product 13
#define divide 14
#define mod 15
#define textone 500
#define texttwo 600
#define result 700

char str[50];

CMainFrame::CMainFrame()
{
Create(NULL, L"MENU BUILDING");
text1.Create (WS_CHILD | WS_VISIBLE | WS_BORDER, CRect(5,10,120,30), this, textone);
text2.Create (WS_CHILD | WS_VISIBLE | WS_BORDER, CRect(140,10,255,30), this, texttwo);
res.Create (WS_CHILD | WS_VISIBLE | WS_BORDER, CRect(275,10,390,30), this, result);

text1.GetWindowText(str1);
text2.GetWindowText(str2);

wsprintf (str,L"%s",str1 );
a=atol(str);

wsprintf (str,L"%s",str2 );
b=atol(str);

//wsprintf ( a,L"%s",str1);
//wsscanf(str1,"%ld",&a);
//a=atol(str);
//wsprintf ( (LPWSTR)str,L"%c",str2 );
//wsprintf ( b,L"%s",str2 );
//b=atol(str);
//wsscanf(str2,"%ld",&b);

b1.Create (L"+", WS_CHILD | WS_VISIBLE | BS_DEFPUSHBUTTON, CRect(5,50,30,70), this, plus);
b2.Create (L"-", WS_CHILD | WS_VISIBLE | BS_DEFPUSHBUTTON, CRect(45,50,70,70), this, minus);
b3.Create (L"*", WS_CHILD | WS_VISIBLE | BS_DEFPUSHBUTTON, CRect(85,50,110,70), this, product);
b4.Create (L"/", WS_CHILD | WS_VISIBLE | BS_DEFPUSHBUTTON, CRect(125,50,150,70), this, divide);
b5.Create (L"%", WS_CHILD | WS_VISIBLE | BS_DEFPUSHBUTTON, CRect(165,50,190,70), this, mod);

//font.CreateFont(20,0,0,0,20,0,0,0, ANSI_CHARSET,OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,DEFAULT_QUALITY,DEFAULT_PITCH|FF_DONTCARE,L"arial");
//sta.SetFont(&font);
}

BEGIN_MESSAGE_MAP( CMainFrame, CFrameWnd)
ON_BN_CLICKED (plus, addition)
ON_BN_CLICKED (minus, substruction)
ON_BN_CLICKED (product, production)
ON_BN_CLICKED (divide, dividation)
ON_BN_CLICKED (mod, modulation)
END_MESSAGE_MAP()

void CMainFrame::addition()
{
c=a+b;

}
void CMainFrame::substruction()
{
c=a-b;

}
void CMainFrame::production()
{
c=a*b;

}
void CMainFrame::dividation()
{
c=a/b;
//SetDlgItemInt(result,UINT(c),1);
}
void CMainFrame::modulation()
{
c=a%b;
sprintf(str,"%ld",c);
//SetDlgItemInt(result,UINT(c),1);
CClientDC dc(this);
//wsprintf(str1,"%ld",c);
//res.SetWindowText(str1);

//dc.TextOut(50, 50, L"goutom", 6);
//wsprintf((LPWSTR)str, L"%c", c);
dc.TextOut(280, 15, (LPCTSTR)str, strlen(str));
//str1.Format(L"%ld",c);
//res.SetWindowText(str1);
}

//SetDlgItemInt(IDC_BUTTON4,UINT(c),1);

BOOL CExerciseApp::InitInstance()
{
m_pMainWnd = new CMainFrame;
m_pMainWnd->ShowWindow(SW_NORMAL);
m_pMainWnd->UpdateWindow();

return TRUE;
}

CExerciseApp theApp;

// when i run this code , it run but not give me a error message. plz solve my error.

Re: where is my fault?

Richard MacCutchan6-Nov-09 0:03

Richard MacCutchan

6-Nov-09 0:03

goutom roy wrote:
when i run this code , it run but not give me a error message. plz solve my error.

Are you saying that it runs correctly? If so then there is nothing to fix. However, if you are saying it does give an error message, then please tell us what the message is.

Re: where is my fault?

Michael Schubert6-Nov-09 0:22

Michael Schubert

6-Nov-09 0:22

goutom roy wrote:
when i run this code , it run but not give me a error message. plz solve my error.

Assuming you mean the opposite of what you wrote - Why don't you just step through the code with the debugger and see where it fails?
Also, next time you post your code please embed it in the "code block" tags.

Re: where is my fault?

David Crow6-Nov-09 3:27

David Crow

6-Nov-09 3:27

goutom roy wrote:
...it run but not give me a error message. plz solve my error.

Contradiction.

"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

how to place CFromview on CDialog? [modified]

jinlsg5-Nov-09 22:22

jinlsg

5-Nov-09 22:22

could i place a CFromView class on a CDialog class int a dialog-based app?
how to place CFromview on CDialog?

I mean: I have a dialog template with CFromView class ,could I doModal this dialog?

modified on Sunday, November 8, 2009 7:40 PM

Re: how to place CFromview on CDialog?

Adam Roderick J5-Nov-09 22:59

Adam Roderick J

5-Nov-09 22:59

Do you mean CFormView?

Величие не Бога может быть недооценена.

Re: how to place CFromview on CDialog?

David Crow6-Nov-09 3:28

David Crow

6-Nov-09 3:28

Why would you even want to? Confused | :confused:

Just add the controls you need to the dialog template.

Re: how to place CFromview on CDialog?

baerten6-Nov-09 3:53

baerten

6-Nov-09 3:53

Hi,

you can add a TabWnd to the Dialog.
Then you can add a CFormView to this TabWnd.
When you move/resize the TabWnd, you can "hide" the TabWnd and you only see the active CFormView.
Naturally you can switch the View into the TabWnd with another View...

I hope this helps you

Greetings

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