QTimer and modeless dialog

[artome]

Hi,

I was faced with a very strange behavior. Not critical as I can do it other way but I would like to know why it happens.
I have a qt designer class that I use as a modeless dialog In a mainwindow application.

If i defined in my mainwindow.h a pointer to a QTimer variable my application always gives segfault at the call of the modeless dialog show(), regardless i do not even use or mention my QTimer pointer anywhere else in the program. Any no modeless dialogs work just fine.
For my application to work I only need to comment the Qtimer *timer declaration in mainwindow.h

I have no problem if i just define the timer in any of the mainwindow functions in mainwindow.cpp, and that's why this problem is not critical, but for me, at least, is very strange. It took me a large amount of hours to discovered that the segfault was due to the fact that I had a QTimer pointer defined in mainwindow.h as I couldn't spot any relation with that declaration, not even used anywhere else, and the modeless dialog.

kind regards,

[mvuori]

I would suggest that this happens because of either
1) A corrupted build - try a clean and rebuild

2) A compiler or linker bug

3) Some other hidden bug is the real culprit; this piece of code just is a catalyst

...Of course, you should not have unused variables in your code... Perhaps the problem would go away if you used the variable.

[amleto]

having an uninitialised pointer anywhere doesn't cause a seg fault inherently. I would suggest you still have a problem somewhere

[high_flyer]

To say what the problem is, we should be able to see your code.

[artome]

To say what the problem is, we should be able to see your code.

I understand that. However it is a huge amount of code. I'm going to try to replicate the problem with a small ad-hoc application as I'm really worried about having an hidden bug completely unrelated. I'm assembling an application to be used by many co-workers in academic and scientific environment and it is really big.

If I'm able to replicate the problem with a smaller code sample I'll post it again.

Many thanks.

[wysota]

Sometimes it is enough to run your program with a debugger and post the backtrace of the crash. Just be sure to build the application in debug mode.

[high_flyer]

a full clean and a rebuild might also help.