Writing to statusBar causes bug in my application

[amleto]

int* p;
*p; <--- bang!

You deref an uninitialised pointer and you get a crash. Did you use your debugger yet? You haven't mentioned anything, and it should be your first point of call**. You should be looking for horses before you blame zebras...

**
edit: oh yes, you said you can't expand it. Didn't that seem strange to you? I wonder why it's not working? Probably because it hasn't been initialised...

[Yes]

int* p;
*p; <--- bang!

Ah, okay this is what you meant with un-initialized. Yes that is very likely. I thought this was what d_stranz was referring to when he mentioned memory corruption, since an un-initialized pointer easily can lead to memory corruption (I guess), and I thought you were referring to an uninitialized float (since the bug was that I got a very strange value for a float, although I didn't mention it).

Did you use your debugger yet?

No, I'm sorry I haven't had the opportunity yet, so maybe it's stupid of me to ask more questions. But I am going to do it soon and get back to this thread when I have found the reason for the bug.

edit: oh yes, you said you can't expand it. Didn't that seem strange to you? I wonder why it's not working? Probably because it hasn't been initialised...

Do you mean that the ui object hasn't been initialized? The ui object must have been initialized, since my main window constructor definition starts like this:

mainwin::mainwin(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::mainwin)
{

mainwin::mainwin(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::mainwin)
{

To copy to clipboard, switch view to plain text mode 

and that's the constructor I use when I'm creating the mainwin object, so the ui object has been initialized with an initializer.

I'm thinking that the ui object has been corrupted, and that I have some uninitialized pointer somewhere that I'm using, like you said. But how can I find places where I'm dereferring uninitialized pointers?

[Spitfire]

What about objects inside ui?
Are you calling ui->setupUi(this)?

I'm guessing you are, otherwise you wouldn't see anything, but I may be wrong.

[amleto]

But how can I find places where I'm dereferring uninitialized pointers?

attach your debugger when your program crashes / look at the call stack when debugging and the error occurs.