C / C++ / MFC

Re: access violation on win2000 service pack 4

19-Jan-05 22:16

Likely a bug in your code that has always been there and decided today is the day to show up. Debuggers were created to help track down such problems and VC has a very good one.

Neville Franks, Author of ED for Windows www.getsoft.com and Surfulater www.surfulater.com "Save what you Surf"

attias gabi20-Jan-05 11:03

attias gabi

20-Jan-05 11:03

dear neville
stop shuving your ED, it is not the place. THANKS FOR YOUR HELP

out of memory error

vc-programmer-19-Jan-05 21:03

vc-programmer-

19-Jan-05 21:03

when i run this code,message box appear "out of memory error".

someone please explain me.Why?
following my code--->>

void CIPAddressDlg::OnButton1()
{
CListBox *pList = (CListBox*) GetDlgItem(IDC_LIST2);
pList->ResetContent();

PMIB_IPNETTABLE pIPNetTable = NULL;
PMIB_IPNETROW pIPNetRow;
in_addr ia;
char *szTypes[4] = {"Other", "Invalid", "Dynamic", "Static"};

GetIpNetTable((PMIB_IPNETTABLE) m_pBuffer, &m_ulSize, TRUE);
m_pBuffer = new BYTE[m_ulSize];
if (NULL != m_pBuffer)
{
pList->AddString("Start get ip net table");
m_dwResult = GetIpNetTable((PMIB_IPNETTABLE) m_pBuffer, &m_ulSize, TRUE);
if (m_dwResult == NO_ERROR)
{
pIPNetTable = (PMIB_IPNETTABLE) m_pBuffer;

for ( unsigned int x = 0; x < pIPNetTable->dwNumEntries; x++)
{
pIPNetRow = &(pIPNetTable->table[x]);

m_strText.Format(" Index: %lu\r\n", pIPNetRow->dwIndex);
pList->AddString(m_strText);

m_strText.Format("MAC address length: %lu\r\n", pIPNetRow->dwPhysAddrLen);
pList->AddString(m_strText);

m_strText.Format(" MAC address: %02x-%02x-%02x-%02x-%02x-%02x\r\n",
pIPNetRow->bPhysAddr[0],
pIPNetRow->bPhysAddr[1],
pIPNetRow->bPhysAddr[2],
pIPNetRow->bPhysAddr[3],
pIPNetRow->bPhysAddr[4],
pIPNetRow->bPhysAddr[5]);
pList->AddString(m_strText);

ia.S_un.S_addr = pIPNetRow->dwAddr;
m_strText.Format(" IP address: %s\r\n", inet_ntoa(ia));
pList->AddString(m_strText);

m_strText.Format(" Type: %s\r\n", szTypes[pIPNetRow->dwType - 1]);
pList->AddString(m_strText);

}
}
else
{
m_strText.Format("GetIpNetTable() failed.Result = %lu\r\n", m_dwResult);
pList->AddString(m_strText);
}

delete [] m_pBuffer;
}
}

Re: out of memory error

Le Ridder Noir19-Jan-05 22:48

Le Ridder Noir

19-Jan-05 22:48

vc-programmer- wrote:
GetIpNetTable((PMIB_IPNETTABLE) m_pBuffer, &m_ulSize, TRUE);
m_pBuffer = new BYTE[m_ulSize];

This is strange

typedef struct _MIB_IPNETTABLE {
DWORD dwNumEntries; // number of entries in table
MIB_IPNETROW table[ANY_SIZE]; // array of ARP entries
} MIB_IPNETTABLE, *PMIB_IPNETTABLE;

Le Ridder Noir

Considderd to be the worlds fastest knoppenbonker. three years of working experience with the worlds fastest copie paster(about 2000 lines a minute). And experience with the one and only NewEra Guru and Crystal Ace.

Re: out of memory error

Mike Dimmick20-Jan-05 2:16

Mike Dimmick

20-Jan-05 2:16

The problem is that m_ulSize (assuming that's a class member) is default-initialised by the debug memory allocator to 0xcccccccc, and you've not set it the first time you use it. GetIpNetTable says that's big enough (and incidentally writes the table to the garbage pointer you probably provided as the first argument) and doesn't set m_ulSize to anything. You then try to get new to allocate a huge buffer, which fails and produces the 'out of memory' error.

In C and C++, you must always initialise every variable you use. Failing to do this inevitably leads to some problem where you've used an uninitialised value.

Since the lifetime of the buffer pointed to by m_pBuffer is the length of this method (you delete it at the end), I'd make m_pBuffer a local variable instead. I'd also make m_ulSize a local variable, along with m_strText.

Something you've not considered is that the size of the table can change between calls to GetIpNetTable. If another ARP request occurs between the calls, the size will change. A common way of handling this problem is simply to use a while loop, quitting when the error is no longer ERROR_INSUFFICIENT_BUFFER.

A fixed version follows:

void CIpNetTableDlg::OnButton1() 
{
    CListBox *pList = (CListBox*) GetDlgItem(IDC_LIST2);
    pList->ResetContent(); 
 
    PMIB_IPNETTABLE pIPNetTable = NULL;
    PMIB_IPNETROW pIPNetRow;
    in_addr ia;
    char *szTypes[4] = {"Other", "Invalid", "Dynamic", "Static"};
 
    BYTE* pBuffer = NULL;
    ULONG ulSize = 0;
    DWORD dwError = GetIpNetTable((PMIB_IPNETTABLE) pBuffer, &ulSize, TRUE);
    CString strText;
 
    while ( ERROR_INSUFFICIENT_BUFFER == dwError )
    {
        delete[] pBuffer;
        pBuffer = new BYTE[ulSize];
 
        if ( pBuffer == NULL )
            break;
 
        dwError = GetIpNetTable((PMIB_IPNETTABLE) pBuffer, &ulSize, TRUE);
    }
 
    if ( dwError == NO_ERROR )
    {
        pIPNetTable = (PMIB_IPNETTABLE) pBuffer;
 
        for ( unsigned int x = 0; x < pIPNetTable->dwNumEntries; x++)
        {
            pIPNetRow = &(pIPNetTable->table[x]);
 
            strText.Format(" Index: %lu", pIPNetRow->dwIndex); 
            pList->AddString(strText);
 
            strText.Format("MAC address length: %lu", pIPNetRow->dwPhysAddrLen); 
            pList->AddString(strText);
 
            strText.Format(" MAC address: %02x-%02x-%02x-%02x-%02x-%02x", 
                pIPNetRow->bPhysAddr[0],
                pIPNetRow->bPhysAddr[1],
                pIPNetRow->bPhysAddr[2],
                pIPNetRow->bPhysAddr[3],
                pIPNetRow->bPhysAddr[4],
                pIPNetRow->bPhysAddr[5]); 
            pList->AddString(strText);
 
            ia.S_un.S_addr = pIPNetRow->dwAddr;
            strText.Format(" IP address: %s", inet_ntoa(ia)); 
            pList->AddString(strText);
 
            strText.Format(" Type: %s", szTypes[pIPNetRow->dwType - 1]); 
            pList->AddString(strText);
        }
    }
    else
    {
        strText.Format("GetIpNetTable() failed.Result = %lu", m_dwResult);
        pList->AddString(strText);
    }
 
    delete [] pBuffer;
}

Stability. What an interesting concept. -- Chris Maunder

GetKeyState

vidhyas19-Jan-05 21:03

vidhyas

19-Jan-05 21:03

Is it that GetKeyState can be used only for Toggle keys and control keys like alt,ctrl, Esc , Enter .etc...
Can i use GetKeyState function to get the state of alphabet keys like A - Z or a -z... If so how ?? The argument passed should be the scan code of the character or Virtual Key codes ??? Plz help...thank u

Neville Franks19-Jan-05 22:15

19-Jan-05 22:15

You need to test if the Shift Key is down - VK_SHIFT from memory. Also CapsLock.

Neville Franks, Author of ED for Windows www.getsoft.com and Surfulater www.surfulater.com "Save what you Surf"

vidhyas19-Jan-05 22:19

vidhyas

19-Jan-05 22:19

Can someone explain me how to do this ?? plz....with a simple sample code...thank u

Neville Franks19-Jan-05 22:26

19-Jan-05 22:26

Sure:

  // GetKeyState() returns with hi-bit set if key was down when msg was sent
#define KEY_DOWN( X )   ( (X) & 0x8000 )


/*  Returns true if the Shift key is down.
 */
BOOL
kb_shift_down()
{
    return KEY_DOWN( GetKeyState( VK_SHIFT ) ) != 0;
}

Neville Franks, Author of ED for Windows www.getsoft.com and Surfulater www.surfulater.com "Save what you Surf"

vidhyas19-Jan-05 22:40

vidhyas

19-Jan-05 22:40

Thanks for ur patience friend...But still my doubt was how to get the key state of alphabet keys...ie A-Z or a-z ...
should i give as GetKeyState('A') or
GetKeyState(Scancode of the character)
Thank u

Neville Franks20-Jan-05 0:40

20-Jan-05 0:40

You use the Virtual Key Code.

From WINUSER.H

/* VK_0 thru VK_9 are the same as ASCII '0' thru '9' (0x30 - 0x39) */
/* VK_A thru VK_Z are the same as ASCII 'A' thru 'Z' (0x41 - 0x5A) */

So for 'a' or 'A' you would use GetKeyState( 'A' ). For F8 VK_F8 etc.

I don't understand why you are confused about this as it is quite clear in the docs: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/userinput/keyboardinput/keyboardinputreference/keyboardinputfunctions/getkeystate.asp[^]

It is also easy enough to test this yourself with some simple sample code.

Neville Franks, Author of ED for Windows www.getsoft.com and Surfulater www.surfulater.com "Save what you Surf"

Anonymous20-Jan-05 2:45

Anonymous

20-Jan-05 2:45

Yes , i can understand friend...but this case works out in a single machine..But in Client and Server concept it fails..I use the same GetKeyState() fn to retrieve the keystate...I check for its return value...

getKey = ::GetKeyState(vk);

if(getKey & 0xF000)
printf("%c pressed 0xF000\n",tempbuffer[c]);

else if(getKey & 0x000F)
printf("%c releases 0x000F\n",tempbuffer[c]);

else if(getKey & 0x0001 == 0x0001)
printf("%c Key is toggled\n",tempbuffer[c]);

else if( getKey & 0x8000 == 0x8000)
printf("%c Key is pressed\n",tempbuffer[c]);

else
printf("%c key is neither pressed nor toggled",tempbufferc]);
}

For the above cases

for some of the characters condn. fails and so the message
"Key is neither pressed nor toggled " message gets printed.

What can i do for this ?

Thank u

cdhtmldialog

lirik19-Jan-05 19:47

lirik

19-Jan-05 19:47

When using cdhtmldialog in MFC, the default html file is embedded in the resource. But can I load the html file somewhere in my local machine? thanks for reading.

Re: cdhtmldialog

Neville Franks19-Jan-05 22:33

VC7 IDE - Custom Document Editors

19-Jan-05 22:33

Yes this is possible. Have you searched the Articles here at CP. Also check out Ehsan's articles at: http://www.beginthread.com/Contributor/Ehsan/ViewAllArticles[^] which have been of great help with Surfulater.

Neville Franks, Author of ED for Windows www.getsoft.com and Surfulater www.surfulater.com "Save what you Surf"

peterchen19-Jan-05 19:17

peterchen

19-Jan-05 19:17

In VC6, you could add an "Active Document Server" to your project, which would open an in-place-editor in the Devstudio IDE. (With all thebenefits like automatic saving when starting a build)

Can anything similar be done in VC7.1? ADS don't seem to work at all. How?

I never really know a killer from a savior
boost your code || Fold With Us! || sighist | doxygen

How to detect the activity of specified device?

ErisonWu19-Jan-05 18:51

ErisonWu

19-Jan-05 18:51

If I want to detect the activity(Playing or Recording) of audio device, how can I do?

Is there any Windows API function, Service, or Driver solution?

In addition, how to detect the activity of devices like bluetooth, wireless...etc

title bar

Member 2996919-Jan-05 18:04

Member 29969

19-Jan-05 18:04

Hi folks,
I have cretaed an SDI application in vc++.
Now i want to change the font of text in the title bar.
How do i do that?

namaskaaram19-Jan-05 18:19

namaskaaram

19-Jan-05 18:19

use CWnd::SetWindowText() function.....

hope that helpz.....

cheerz.....
Big Grin | :-D

Member 2996919-Jan-05 20:07

Member 29969

19-Jan-05 20:07

Dear rateep,
Setwindowtext() only displays the desired text in the title bar. But my requirement is to change the font of that text.
So please help me find the solution.
Regards,
srinipkweb

toxcct20-Jan-05 2:19

toxcct

20-Jan-05 2:19

vote 1...

SetWindowText() sets a caption, not the font Frown | :(

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Garth Watkins19-Jan-05 20:34

Garth Watkins

19-Jan-05 20:34

I think the only way you're going to do that is by painting the frame window yourself. In other words by intercepting the WM_NCPAINT, and painting the non client areas (which include the title bar) yourself

Member 2996919-Jan-05 23:40

Member 29969

19-Jan-05 23:40

HI Garth,
Thanks for the response.
But will you please give the exact code for painting the frame and its location within the application code.