dlete pointer.

[toxcct]

Ajeesh c v wrote:

int * p = NULL; delete p; how the datas will be deleted from the location which is pointed by p initialy. since u r saying to delete the pointer after asigning the pointer to null.

he doesn't say it is the things to do... the cases enumerated are possible causes for a crash when deleting a pointer X|

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TOXCCT >>> GEII power

[VisualCalc 3.0  updated ][Flags Beginner's Guide  new! ]

[Cedric Moonen]

Ajeesh c v wrote:

how the datas will be deleted from the location which is pointed by p initialy. since u r saying to delete the pointer after asigning the pointer to null.

That's probably your problem. When you do this:

int* pTest;
if (pTest)
delete pTest;

You will have an excpetion because you try to delete memory that is unitianalized (you can only delete memory that has been allocated with new). So, to be sure not to delete this 'unexistant' memory, assign NULL to the pointer. This is safe.

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Cédric Moonen Software developer
Charting control

[Viorel]

According to documentation (http://msdn2.microsoft.com/en-us/library/h6227113.aspx[^]), “You can [...] use delete on a pointer with the value 0”. Therefore instead of

if( p != NULL )
{
    delete p;
    p = NULL;
}

you can use

delete p;
p = NULL;

However, this does not belong to original topic. I think you should put a breakpoint at the line where your block of memory is allocated and the pointer is assigned. Then investigate the pointer’s value and the content of the memory block. Then stop on the line where the pointer is deleted. Check if the pointer contains right address value. Try to use step-be-step execution during deletion. Perhaps the pointer points to an object having destructor, and the problem is within this function.

[see me]

ok... I think the problem is occuring due to this reason. am initializing the pointer from thread...adn try to delete it from another thread.. if there is any chance of occuring exception???? Please help me... yours faithfully ajeeshcv

[toxcct]

as far as you don't answer my questions, i don't help you furthermore. :zzz:

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TOXCCT >>> GEII power

[VisualCalc 3.0  updated ][Flags Beginner's Guide  new! ]

[see me]

Thats a very precious information for me. Thank you.. yours faithfully ajeeshcv

[Viorel]

I think this causes problems if your project’s configuration does not allow multi-threading. You should open the project’s properties dialog and be sure that the C/C++ --> Code Generation --> Runtime Library option contains a right value related to multi-threading. Then rebuild the application.

[see me]

The pointer is of a dialog. Initialization: CMyDialog* pMyDialog; pMyDialog = new CMyDialog; pMyDialog->EndDialog(0); if(pMyDialog) { delete pMyDialog; pMyDialog = 0; } yours faithfully ajeeshcv

[see me]

Thank you... I don't know it will work or not. Let me check. yours faithfully ajeeshcv

[Hamid Taebi]

im not sure your problem is this but how to create dialog? and if you run your code i think you get a error in pMyDialog->EndDialog(0); now try this and send me if you have a error CMyDialog* pMyDialog; pMyDialog = new CMyDialog; pMyDialog->Create(IDD_TEST);//id from dialog pMyDialog->EndDialog(0); delete pMyDialog ; pMyDialog = 0;_**

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**_

whitesky

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[jhwurmbach]

Ajeesh c v wrote:

am initializing the pointer from thread...adn try to delete it from another thread

May one thread still be accessing the memory you just deleted? Maybe using smart-pointers (like those from boost.org)[^]can help you? Or at least an object which can delete itself via a member function?

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"We trained hard, but it seemed that every time we were beginning to form up into teams we would be reorganised. I was to learn later in life that we tend to meet any new situation by reorganising: and a wonderful method it can be for creating the illusion of progress, while producing confusion, inefficiency and demoralisation." -- Caius Petronius, Roman Consul, 66 A.D.