Can't remove memory leaks from MFC application

Question

0.00/5 (No votes)

See more:

I have an MFC SDI app with a tree-view on the left (explorer-style).
I am trying to ensure there are no memory leaks and am using the following code to do so:

#ifdef _DEBUG
   		CMemoryState oldMemState, newMemState, diffMemState;
   		oldMemState.Checkpoint();
#endif
#ifdef _DEBUG
   		newMemState.Checkpoint();
   		if( diffMemState.Difference( oldMemState, newMemState ) )
   		{
			TRACE("Memory leaked!\n" );
      		AfxMessageBox(L"Memory leaked!\n" );
   		}
#endif

I am finding that I cannot get rid of memory leaks e.g. there is a memory leak between when I open a file that populates the tree-view (CTreeCtrl) and when I close the file and empty the tree-view. I delete all the tree items and call delete on all the pointers to the data structs held within each tree item, but there is still some memory leak somewhere. I call the open and close via MFC message handlers in the CMyDoc class. and I put the memory checks at the start of the OnOpenDoc method and at the end of the OnCloseDoc method.

I am wondering if there are unavoidable leaks when using MFC as there is stuff going on that I am not controlling.

Also, can anyone tell me which numbers to look at in the CMemeoryState struct to see how much memory is used at any time.

Is there a better (free) way to check for memory leaks in my case?

Posted 11-Dec-11 23:48pm

Jackie Lloyd

Updated 11-Dec-11 23:49pm

v2

Add a Solution

Comments

LaxmikantYadav 12-Dec-11 6:51am

Please share your code so we can help you.

2 solutions

Solution 2

Getting the message "Memory leaked", doesnt mean that you have a memory leak. It means that only some difference is there in memory conumption at that time. When using MFC there are no unavoidable leaks, may be there is some memory consumption. for example see the below code

C++

CMemoryState new, old, diff;
old.CheckPoint();
m_csMyStr.LoadString( IDS_MYSTRING );
old.CheckPoint();
if( diff.Difference( old, new ))
{
    AfxMessageBox( "Mem Leak" );
}

It gives the message "Mem Leak". But is there any memory leak that the programmer needs to resove. No right?

but you need to make sure that what all you have newed, you just need to delete
If you debug your code, you can find the memory leak in visual studio IDE itself. In debug window.

Posted 12-Dec-11 0:58am

Resmi Anna

Comments

Zarina-dev 30-Nov-22 21:51pm

What to do if it doesn't show memory leak information in output window?

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

KarstenK · Accepted Answer · 2011-12-12T00:15:00

Solution 1

you better look at the memory leaks of your code. Look in the content of the leaked memory. I guess that you dont delete all allocated sub-objects. You wont "call delete on all the pointers to the data structs" ;-)

In a tree you need to work recursly what needs a lot of care.

Posted 12-Dec-11 0:15am

KarstenK

Comments

Jackie Lloyd 12-Dec-11 6:51am

Yes, good point, but I had done that. However, now when I run the memory leak check it shows no memory leak! Before it was showing a very small memory leak. I don't know why it has changed now - a mystery to me, but at least it all seems happy now. Thankyou!