Default Win32 project has constant number of memory leaks

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INTRODUCTION AND RELEVANT INFORMATION:

The original project I work on has small memory leaks, so I have decided to perform a small test so I can detect what could cause them.

I have created a Win32 project using Visual Studio wizard. I haven't added anything, I have just left it as it was created with the wizard. I have used the tool GDIView ( http://www.nirsoft.net/utils/gdi_handles.html[^] ) to see if there are any inherent GDI leaks.

PROBLEM:

Each time I resize the window, this tool shows that there are +3 regions that my application leaks.

MY EFFORTS TO SOLVE THE PROBLEM:

Since the project was made by the Visual Studio wizard, I have tried to create a simple project from scratch, but the same +3 regions appear.

Reading through some articles on CodeProject about regions I have stumbled upon some demo applications that demonstrate the usage of them.

When I turn on GDIView these applications also leak +3 regions.

All of this is verified when I turn on Task Manager to see if the small memory leak is really occurring-it does occur since the memory slightly rises and stays constant afterwards no matter how many times I resize the window.

I use Microsoft Visual Studio 2008 Express Edition, but the problem was detected when empty project is created in regular Visual Studio 2008 as well.

I work on Windows XP, but the same effect happens on Windows 7.

QUESTION:

Why is this happening and how to eliminate these small memory leaks?

Thank you.

Best regards.

Posted 18-Dec-13 6:37am

AlwaysLearningNewStuff

Updated 18-Dec-13 8:32am

v2

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Comments

Richard MacCutchan 18-Dec-13 12:46pm

Given thay you have not shown us any of the code, or pointed out where the leaks occur, it's impossible to suggest anything.

AlwaysLearningNewStuff 18-Dec-13 12:53pm

That is exactly the problem!

I have just made the simplest Win32 projest with Visual Studio wizard. Nothing was added, and yet GDIView shows leak of 3 regions. So strange...

Thank you for the comment.

Best regards.

CPallini 18-Dec-13 12:55pm

How do you check such memory leaks? I made a test with default Visual Studio 2012 generated Win32 App and nothing changes in GDIView, on application window resize.

AlwaysLearningNewStuff 18-Dec-13 13:20pm

Here is how I do it:

First run GDIView;
Run demo application;
Resize it a bit;
Look at the columns in the GDIView;

Under regions column, and in the column All GDI will stand +3.

Regards.

CPallini 18-Dec-13 14:19pm

OK, I am glad to learn new staff. Following your instructions I see no changes in All GDI (it is 17). My system: Visual Studio 2012 running on Windows 8.

AlwaysLearningNewStuff 18-Dec-13 14:38pm

In the Options menu, please activate Show Counters+Changes option.

Next to the number of the GDI objects, you will see square brackets.

If everything is properly cleaned up they should contain 0 ( for example 17[0] ).

After you perform resize, there will be +3 in the square bracket, indicating the leak.

Regards.

CPallini 18-Dec-13 15:04pm

Done. Still no changes: 17 [0].
(possibly they improved the code).

AlwaysLearningNewStuff 18-Dec-13 15:20pm

Perhaps you are right. Thank you for your help, I highly appreciate it.

Best regards.

CPallini 18-Dec-13 16:04pm

You are welcome. Tomorrow I'm going to test it on VS2005 (I hope I'll remember!).

AlwaysLearningNewStuff 18-Dec-13 16:26pm

Thank you so much Mr.Pallini.

Best regards.

Sergey Alexandrovich Kryukov 18-Dec-13 12:58pm

To make the question answerable, you need to provide some minimal code sample which should meet SSCCE requirements and reproduce the issue.
—SA

AlwaysLearningNewStuff 18-Dec-13 13:21pm

There is no need for the code, the code is generated by the Visual Studio wizard.
That "empty" project has +3 leaks of the GDI regions, which is what surprizes me, hence the question.

Regards.

Sergey Alexandrovich Kryukov 18-Dec-13 13:29pm

Without any programming artifact, there is nothing to look at.
—SA

AlwaysLearningNewStuff 18-Dec-13 13:34pm

Hmm...
Do you not even wonder how is it possible that application generated with Visual Studio wizard, has memory leaks when its window is resized, even if they are small ones?
Regards.

Sergey Alexandrovich Kryukov 18-Dec-13 13:42pm

Of course I did. This is irrelevant to the wizard. When you get to the problem, you have some artifact to start with, right?
You have a project, or something. The same way, the person who is supposed to do it, need to have the same, only highly simplified.
The best approach is to write the code manually, but there is nothing wrong with auto-generated code. Do you see principle difference?
—SA

AlwaysLearningNewStuff 18-Dec-13 13:59pm

I fear that I do not understand your point.

By reading through the link you have posted, I think I have satisfied the SSCCE principle:

Short:
The question refers to the project generated by the Visual Studio wizard.
Self Contained:
Anyone who has Visual Studio can make/run the project, therefore having the exact same code/application window I have.
And anyone can download GDIView from the link provided in my post.
Correct
It was generated by Visual Studio wizard so all the naming/coding conventions are followed through and it compiles cleanly.
Example
All the elements are there to reproduce the problem-the appearance of the 3 "phantom" GDI leaks that should not be there when the application's window is being resized.

I do not understand what else should I submit to help?

Regards.

Sergey Alexandrovich Kryukov 18-Dec-13 14:17pm

I do understand my own points, not it's your turn. What you say is just excuses. The question is very simple: do you want to get help or not? You see, you usually, provide very thorough descriptions when asking questions, in contrast to most inquirers, but here is the case when you approach does not work. Imagine that someone asked you to find a leak in the code you cannot access. All right, let's dub your question not answerable, that also happens...

Another question: what tells you that there is a leak? What is your leak detection method? We had many questions where people used unreliable methods, such as looking at TaskManager, which should not be trusted, which is a very well known problem...

—SA

AlwaysLearningNewStuff 18-Dec-13 14:25pm

Mr.Kryukov,
There has occurred a misunderstanding between us:

QUOTING:

"Imagine that someone asked you to find a leak in the code you cannot access." ( emphasis is mine ).

ANSWER:

The code can be accessed by anyone who makes a simple Win32 project with Visual Studio application wizard. There is no need to submit the code, in my opinion, when anyone can create "default" win32 project, that is my reasoning.

QUOTING:

"Another question: what tells you that there is a leak? What is your leak detection method? "

I have explained it in my original post, I use GDIView to detect memory leaks.

My sincere apologies for the misunderstanding that occurred.

Regards.

Sergey Alexandrovich Kryukov 18-Dec-13 14:41pm

Sorry, I missed your explanation of your method of detection. However, "slightly rises and stays constant afterwards" is not a description of a leak, it looks like having no leak. If GDIView independently gives you the leak detection, this is a different story.

Also, I see your point. You think that if someone creates a project it give you the code sample. The approach really has a right to exist. However, that's not all. You see, it was hard for me to believe that even the basic default projects give a leak (it that what you say?). As it looks that weird, some detail which usually does not matter may matter. 1) The wizard have some options? 2) OS version? 3) VS version?

—SA

AlwaysLearningNewStuff 18-Dec-13 14:48pm

Thank God we have found "common ground"!

OS is Windows XP, and it happens on Windows 7 too.

VS is Express Edition 2008, but happens on regular VS 2008 too.

As for Wizard options, none of them are relevant to the problem.

And yes, Mr. Kryukov, that was the reason for asking this question, because such a simple project has constant +3 memory leaks.

Again, I am glad that we have finally clarified our differences in opinion. I apologize for the misunderstanding I might have caused.

Best regards.

Sergey Alexandrovich Kryukov 18-Dec-13 16:10pm

Thank your for the detail. Finding common ground is unavoidable, with some patience. I hope you are not irritated, too. :-)
I tend to agree with the answer you referenced. I also suggested it could be false positive, but cannot be 100% sure.
—SA

AlwaysLearningNewStuff 18-Dec-13 16:23pm

If we can test this on Windows 7 the way Mr.Pallini tested on Windows 8, we could determine if this problem originated from them.

All we need is for GDIView to show +3 in All GDI.

By the way, I am not irritated with your comments.

After seeing the manner in which some questions are prepared/asked here, and the attitude of the inquirers I understand that members are used to get incomplete/incoherent type of questions, so they can misunderstand my posts sometimes.

But that is the reason why I structure the questions like this, so everything is thorough and simple for the reader to understand.

Best regards.

Sergey Alexandrovich Kryukov 18-Dec-13 16:38pm

I see. I mentioned irritation because I actually did some redundant/wrong moves based on paying not enough attention to your post. I knew you would understand me. Sometime I do mistakes in interpretation of the questions by the reason you just explained perfectly — unfortunately, there are way too many posts which don't really deserve much attention; many of us easily recognize more decent ones by indirect signs (manners of writing), but false positive/negatives still happen.

At the same time, I still insist that CCSSE posts are quite possible and appropriate even if auto-generated code is involved. The auto-generated code is still code. All right, in the case you described it would be redundant, but should you add just a couple of steps, the CCSSE code sample would already be much better than explanation of those steps. Besides, for everyone's benefit things work better when an inquirer spends more time on the problem.

Cheers,
—SA

AlwaysLearningNewStuff 18-Dec-13 16:47pm

I think I now understand your point of view.
Will remember this for the future posts.
Best regards.

Sergey Alexandrovich Kryukov 18-Dec-13 16:57pm

I already know that you post quite responsibly.
Wish you the best of luck,
—SA

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AlwaysLearningNewStuff · Accepted Answer · 2013-12-18T09:26:00

Solution 1

I do not wish to steal other people's credits so I post here a link to the answer that I think explains really well what is the problem:

http://stackoverflow.com/questions/20664677/default-win32-project-has-constant-number-of-memory-leaks[^]

Posted 18-Dec-13 9:26am

AlwaysLearningNewStuff

Comments

CPallini 18-Dec-13 16:09pm

It looks a great answer, however Win32 little-leaks make me worry a bit.

AlwaysLearningNewStuff 18-Dec-13 16:16pm

Can you do our little test with the Windows 7, instead of Windows 8?

If there is +3 in All GDI, than we can safely assume they have fixed the problem.

Thank you.

EDIT:

I saw your comment above too late :)
Regards.

CPallini 19-Dec-13 2:11am

Today WinXP. Possibly tomorrow Win7.

CPallini 19-Dec-13 3:28am

On WinXp (32 bit, I forgot to mention my Win8 was 64 bit), Visual Studio 2005 generated project I found 33 [+4], that is I got +4 on the very first resize, than no more.
On the same WinXp, a Visual C++ 2010 Express genrated project I found the same result: 33 [+4] with +4 on first resize.
(both tests with debug build launched from within Visual Studio).

AlwaysLearningNewStuff 19-Dec-13 9:19am

Thank you for your help, Mr.Pallini.

I think that this confirms that there are small memory leaks within Win32 projects ( both wizard generated ones and the ones made from "scratch" ).

I just hope that this is caused by the reasons provided in the link in my answer.

I still agree with you, that this is a little bit scary.

Best regards.