QT4.2 corrupted double-linked list and QRadioButton existance

[mtrpoland]

Valgrind?
I do not know whether it is useful as not long time ago I played with FlowLayout example (QT 4.2) and valgrind gave me:

==6237== LEAK SUMMARY:
==6237==    definitely lost: 88 bytes in 3 blocks.
==6237==    indirectly lost: 120 bytes in 10 blocks.
==6237==      possibly lost: 744 bytes in 3 blocks.
==6237==    still reachable: 322,563 bytes in 4,588 blocks.
==6237==         suppressed: 0 bytes in 0 blocks.

==6237== LEAK SUMMARY:
==6237==    definitely lost: 88 bytes in 3 blocks.
==6237==    indirectly lost: 120 bytes in 10 blocks.
==6237==      possibly lost: 744 bytes in 3 blocks.
==6237==    still reachable: 322,563 bytes in 4,588 blocks.
==6237==         suppressed: 0 bytes in 0 blocks.

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Now my 1600+ lines application gives me:

==6214== LEAK SUMMARY:
==6214==    definitely lost: 449 bytes in 32 blocks.
==6214==    indirectly lost: 1,526 bytes in 36 blocks.
==6214==      possibly lost: 744 bytes in 3 blocks.
==6214==    still reachable: 331,034 bytes in 4,629 blocks.
==6214==         suppressed: 0 bytes in 0 blocks.

==6214== LEAK SUMMARY:
==6214==    definitely lost: 449 bytes in 32 blocks.
==6214==    indirectly lost: 1,526 bytes in 36 blocks.
==6214==      possibly lost: 744 bytes in 3 blocks.
==6214==    still reachable: 331,034 bytes in 4,629 blocks.
==6214==         suppressed: 0 bytes in 0 blocks.

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So I suppose that some of those are because of qt libraries... Am I right?

Anyway, I may write some parts of valgrind message after checking my application.

[marcel]

I don't think this is getting anywhere.
If the app is only around 1600 lines, then why don't you post it here?
Would that be possible? Then someone could test it.

Regards

[mtrpoland]

Below are links to working application (I have circumvented the problem above) and package of code files and file containing some data to test program (one humble *.dat file).

Anyway, I would be glad if someone experienced checked some of my code for bugs and bad habits. I know it is difficult to ask you for such thing but marcel suggested such a solution himself.

The "funny" thing is when I de-comment code connected to QTranslator in main.cpp I get SIGSEV gift.
In other words I cannot translate my application using .ts file made by Linguist.

So my inference is that there is some crucial memory management bug in MY code that sometimes throws irrational SIGSEV, blocking me of using certain normal ways of programming.

I just cannot find it!

Program and code package in:
http://www.mjakobczyk.pl/pub/code/

[marcel]

I compiled your application( on Windows, Qt 4.3 ) but I cannot get it to crash( I uncommented the translator lines in main).
Could you say what steps are involved?

Regards

[jpn]

Here's at least one issue that prevents it from launching for me:

void MWin::initialization(void) {
	...
	tableViewWidget = new MyMVC(list); // list is yet uninitialized
	...
	list = new QList<MTR::Book>; // it's being initialized somewhere here afterwards
	...
}

void MWin::initialization(void) {
	...
	tableViewWidget = new MyMVC(list); // list is yet uninitialized
	...
	list = new QList<MTR::Book>; // it's being initialized somewhere here afterwards
	...
}

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I would suggest allocating QList objects on the stack and passing them as references. Allocating them on the heap is more error prone. QList is an implicitly shared class so unmodified copies are cheap.

[marcel]

Yeah, that and correct the following from:

namespace MTR {
class Book;
class SBook;
}

namespace MTR {
class Book;
class SBook;
}

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to:

namespace MTR {
class Book;
struct SBook;
}

namespace MTR {
class Book;
struct SBook;
}

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I was getting a few warnings and a linker error because of this.

Regards

[mtrpoland]

Gentlemen, now all indeed does work. A nod of respect. Thank you very much. Now I see that the key was what highlighted jpn. It destabilized my application.