[Qt-interest] Question about detecting memory leaks!

[Jason H]

This is not a Qt issue.

You made a new int, which is 1 bytes.
You never deleted it. 
Ergo, you have a memory leak.

add:
delete a;
and you will have no more leak.






________________________________
From: Jack Mack <jackmack2000de at yahoo.de>
To: qt-interest at trolltech.com
Sent: Wed, December 15, 2010 8:27:04 AM
Subject: [Qt-interest] Question about detecting memory leaks!


Hi all,

I have a question about detecting memory leaks in my qt based application.

I'm using Qt 4.7.0 with VS2008.

Maybe this is a simple question and I get a fast answer.
This is my snipped out code of my qt based application:

    int* a = new int;
    *a = 1;

When I start the app in debug-mode within VS2008 and finish the app correctly by 
clicking the windows system menu then the output window of VS2008 shows only 
some text like:

...
Thread 'Win32 Thread' (0xf68) finished with code 0 (0x0).
BTMMHOOK 15.12.2010 12:19:31 Thread<0460> Hook DLL unloaded
Thread 'Win32 Thread' (0x132c) finished with code 0 (0x0).
Program "[4052] LineView.exe: Systemown" finished with code 0 (0x0).

When I use the snipped code above in a simple MFC application and run it in  
debug-mode and close it then the following text is showed by output window of 
VS2008:

...
BTMMHOOK 15.12.2010 12:21:16 Thread<0E14> Hook DLL unloaded
Detected memory leaks!
Dumping objects ->
e:\entwicklung\simplemfc\simplemfc\simplemfc.cpp(77) : {565} normal block at 
0x0034B790, 4 bytes long.
 Data: <    > 01 00 00 00 
Object dump complete.
Program "[2160] SimpleMFC.exe: Systemown" finished with code 0 (0x0).

I think that's strange! The compiler warning options are the same.
Yes, I know that all classed inherited by QObject are deleted automatically and 
"delete" is not neccessary. But the snipped code above causes definitly a memory 
leak.

Can someone explain that to me?

Thanks a lot,
jack


      
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