Access Violation 0xC0000005 - C / C++ / MFC Discussion Boards

Re: Can Debugger show the values in binary form?

CPallini1-Jan-09 10:32

CPallini

1-Jan-09 10:32

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Application working fine but seems like system has hanged

VCProgrammer31-Dec-08 20:01

VCProgrammer

31-Dec-08 20:01

Hi all,

I have made a dialog based application in vc2008....

I have made a worker thread inside my application, now my problem is when I execute my application everything is running fine but my dialog box start displaying not responding and it looks like system is hanged but after few mintues it displays right output.....

Like everything working fine in background......

I am not getting what is the problem.......

Can anybody tell me how to resolve the problem....

Thanks in advance....

Re: Application working fine but seems like system has hanged

Joseph Marzbani31-Dec-08 20:14

Joseph Marzbani

31-Dec-08 20:14

give us a little more information on what your App is and what you want the working thread to do. (Always do so)

Thank you masters!

Re: Application working fine but seems like system has hanged

Jijo.Raj1-Jan-09 0:13

Jijo.Raj

1-Jan-09 0:13

VCProgrammer wrote:
I have made a worker thread inside my application, now my problem is when I execute my application everything is running fine but my dialog box start displaying not responding and it looks like system is hanged but after few mintues it displays right output.....

Are you doing any lengthy background operation in UI thread? Which ultimately makes your UI freeze. In that case, spawn a new thread and do your background operations there which will make the UI responsive.

Regards,
Jijo.

_____________________________________________________

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checkbox in List control and image

vicky0000031-Dec-08 18:32

vicky00000

31-Dec-08 18:32

Hi all,

I used a list control with check box, and image list.
My aim is check box is in first column and image in second column.
I did as i want.. but one problem is
first image in image list is shown in first column along with check box?
I need to check box alone in first column..

Thanks a lot.

Re: checkbox in List control and image

Nibu babu thomas31-Dec-08 23:22

Nibu babu thomas

31-Dec-08 23:22

vicky00000 wrote:
My aim is check box is in first column and image in second column.

Have you tried LVS_EX_SUBITEMIMAGES and CListCtrl::SetExtendedStyle?

Nibu babu thomas
Microsoft MVP for VC++

Code must be written to be read, not by the compiler, but by another human being.

Programming Blog: http://nibuthomas.wordpress.com

Re: checkbox in List control and image

vicky000001-Jan-09 17:45

vicky00000

1-Jan-09 17:45

Thnks for your replay...
i already used? My question is how to avoid the image appended with check box in first column....?

Access Violation 0xC0000005

whiteclouds31-Dec-08 18:14

whiteclouds

31-Dec-08 18:14

Hi all!
I'm developing an console application with MFC support. Now I meet an exception when I execute the following code:

    CBitmap 	*bitmap;
    CDC 		memDC;
    CRect		rect;
    CWnd *pWnd=m_pWndHide;//->GetWindow(GW_HWNDFIRST);
//    CWindowDC	dc(pWnd);

    memDC.CreateCompatibleDC(&m_hDC);//(&dc);

    // Calculate required height from specified width
    int height = CAH_glo_y * width / CAH_glo_x;

	bitmap = new CBitmap();
    //The next line will occur "Access Violation 0xC0000005"
    bitmap->CreateCompatibleBitmap(&m_hDC, width, height );//(&dc, width, height );
    CBitmap* pOldBitmap = memDC.SelectObject(bitmap);
    // using the current background colour (assume white for the moment)
    memDC.PatBlt(0, 0, width,height, WHITENESS);
    ...

I trace this error into a source file named SBHEAP.c in MFC then. The function stopped in is __sbh_alloc_block. The related code is following:

...
pEntry->pEntryNext = pHead->pEntryNext;
pEntry->pEntryPrev = pHead;
pHead->pEntryNext = pEntry;
pEntry->pEntryNext->pEntryPrev = pEntry;//Stop here
...

I watch the value of pHead->pEntryNext . It is NULL. So I can't access it. But I don't know why and how to resolve it. Confused | :confused:

This code will be executed many times before. But it is wrong when the 3 times. If someone can tell me or give me some good advice, I will be very glad. Thanks!

Regards

whiteclouds

Re: Access Violation 0xC0000005

Nibu babu thomas31-Dec-08 23:16

Nibu babu thomas

31-Dec-08 23:16

whiteclouds wrote:
bitmap->CreateCompatibleBitmap(&m_hDC, width, height );//(&dc, width, height );

Note that if width and height is too big then CreateCompatibleBitmap does fail. Also how did you get m_hDC. Is this a valid DC?

Nibu babu thomas
Microsoft MVP for VC++

Code must be written to be read, not by the compiler, but by another human being.

Programming Blog: http://nibuthomas.wordpress.com

Re: Access Violation 0xC0000005

whiteclouds1-Jan-09 12:46

whiteclouds

1-Jan-09 12:46

Hi, thomas!
Thanks for your reply.
I think I had found the reason. After I delete some variables that aren't be used any more, the exception is missing. But another exception is occur same as this when I use the code following:

time_t  ltime;      // local time
struct  tm  *gmt;   // Greenwich Mean Time
png_time    ttime;  // png format

time (&ltime);  // get the local time---EXCEPTION 0xC0000005 OCCUR HERE!
gmt = gmtime (&ltime);  // convert to gmt
png_convert_from_struct_tm (&ttime, gmt);  // convert to png format
png_set_tIME (png_ptr, info_ptr, &ttime);

I trace this exception into MFC and I found when a function named _mlock was invoked in the __tzset function, the exception occur. The related code like this:

_mlock( _TIME_LOCK );

I don't know the reason and hope you or others can give me some suggestion. Thank you!

Regards!

whiteclouds

processor affinity

RomTibi31-Dec-08 13:49

RomTibi

31-Dec-08 13:49

How can I assign to a certain processor a process?
Can I list the processes assigned to a certain processor?

If possible, in VC++6 Wink | ;)

36. When you surround an army, leave an outlet free.
...
Do not press a desperate foe too hard.

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Re: processor affinity

Mark Salsbery31-Dec-08 15:22

Mark Salsbery

31-Dec-08 15:22

RomTibi wrote:
How can I assign to a certain processor a process?

You can assign a process to selected processor(s) with SetProcessAffinityMask().

RomTibi wrote:
Can I list the processes assigned to a certain processor?

You could enumerate the current processes and check which processors each
is set to use, perhaps using these functions:

EnumProcesses()
OpenProcess()
GetProcessAffinityMask()
CloseHandle()

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: processor affinity

RomTibi1-Jan-09 2:55

RomTibi

1-Jan-09 2:55

Thanks a lot! Smile | :)

36. When you surround an army, leave an outlet free.
...
Do not press a desperate foe too hard.

SUN-TZU - Art of War

conversion problem

wubousc31-Dec-08 10:17

wubousc

31-Dec-08 10:17

Hi,

Could someone please let me know why my code can not pass compilation? (VC++9.0,vista 64-bit)

The problems happens in the "<<" operator overload function. It seems my code can not pass some constness check.

#include <map>
#include <vector>
#include <iterator>
#include <algorithm>
#include <iostream>

using namespace std;

typedef pair<string,int> pairSI;

struct StringToSIPair
{
explicit StringToSIPair(int val) { intVal = val; }

pairSI operator () (string str)
{
pairSI psi = make_pair(str, intVal);
return psi;
}

int intVal;
};

void VecToMap(vector<string> &vecStr, int iniVal, map<string,int> &siMap)
{
transform(vecStr.begin(), vecStr.end(), inserter(siMap, siMap.begin()), StringToSIPair(iniVal));
}

ostream & operator << (ostream &out, map<string, int> &siMap)
{
for(map<string, int>::iterator it = siMap.begin(); it != siMap.end(); ++it)
{
out<<"key: "<<it->first<<" value: "<<it->second<<endl; // the compiler said there is a conversion problem
}

return out;
}

int main()
{
map<string,int> siMap;
vector<string> strVec;

strVec.push_back("bob");
strVec.push_back("alex");
strVec.push_back("alal");

VecToMap(strVec, 4, siMap);

cout<<siMap<<endl;

return 0;
}

regards,
Bob

Re: conversion problem

Rick York31-Dec-08 11:47

Rick York

31-Dec-08 11:47

First, I would recommend defining a type for your map. Something like :

typedef map<string,int> StringIntMap;

This could simplify some of the code.

Second, try using some temporary variables of the correct type to save the values of the first and second members of the iterator and then use those temps for the output. That should show you exactly what the compiler is expecting for variable types and allow you to cast if and as needed.

Re: conversion problem

wubousc31-Dec-08 13:32

wubousc

31-Dec-08 13:32

Hi, Rick,

Do you mean I should change the code like this?

ostream & operator << (ostream &out, map<string,> &siMap)
{
  for(map<string,>::iterator it = siMap.begin(); it != siMap.end(); ++it)
  {
string key = it->first;
int value = it->second;
out<<"key: "<<key<<" value: "<<value<<endl;
  }

  return out;
}

However, it doesn't fix the problem. I am confused because I think ostream has the ability to output string no matter it is const or not.

regards,
Bob

How to separate a specified number of Bits from a DWORD?

Joseph Marzbani31-Dec-08 8:16

Joseph Marzbani

31-Dec-08 8:16

Suppose we have a number of type DWORD and we want to extract four 6-bit number and a byte from it. Some thing like this:

(DWORD) ---> 10100101101000110100011010101001

(Result) ---> 101001 011010 001101 000110 10101001

If you want to introduce me 'Bit Field Operators', be aware! It does NOT work in this manner.

Thank you masters!

Re: How to separate a specified number of Bits from a DWORD?

harold aptroot31-Dec-08 8:25

harold aptroot

31-Dec-08 8:25

Just shift and mask it?
the byte: dword & 0xFF
last 6bit value: (dword >> 8) & 0x3F
next 6bit value: (dword >> 14) & 0x3F
etc?

Would that work?

Re: How to separate a specified number of Bits from a DWORD?

Jijo.Raj31-Dec-08 11:54

Jijo.Raj

31-Dec-08 11:54

Possibly another approach is to use union. Just check the following code snippet.

// Disable the packing.
#pragma pack(1)

// Use the union to access bytes of DWORD.
union DWordParser
{
    DWORD DwordValue;
    BYTE Bytes[4];
};

// Using the parser.
DWordParser Parser;
Parser.DwordValue = 255;

// Now get 6 bits of 3ed byte.
BYTE ThirdByte = Parser.Bytes[2] & 0x3F;

But you have to sacrifice performance for readability. Wink | ;)

Regards,
Jijo.

_____________________________________________________

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

Re: How to separate a specified number of Bits from a DWORD?

krmed31-Dec-08 14:12

krmed

31-Dec-08 14:12

Can you explain why you feel that bit fields won't work for you?

Karl - WK5M
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Re: How to separate a specified number of Bits from a DWORD?

Richard Andrew x641-Jan-09 6:52

Richard Andrew x64

1-Jan-09 6:52

krmed wrote:
Can you explain why you feel that bit fields won't work for you?

I'm guessing it's because he didn't know how to use them properly. Poke tongue | ;-P

Stuck in ShowWindow

dj440031-Dec-08 4:41

dj4400

31-Dec-08 4:41

Hi all,
I have a multithreaded application written in c++ vs6.
I try to create a new dialog within an existing dialog in that application and when i call
ShowWindow(SW_SHOW)for the new dialog it doesnt do anything.
If i put a break point there, it seems that it stops in the call to ShowWindow and doesnt continue the execution.
Can someone explain this strange behavior and suggest a way to overcome this problem?
Thanks
Simon.

Re: Stuck in ShowWindow

Mark Salsbery31-Dec-08 6:13

Mark Salsbery

31-Dec-08 6:13

All these dialogs are created on the same thread?

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]