Memory managment

[giu_sca]

hello,

i have a strange behavior in my app.

I have several QWidget in my app, for each QWidget I have created all object at run time, I haven't used GUI interface.
I have added to each object this attribute

setAttribute(Qt::WA_DeleteOnClose,true);

and I have declared them into my header files, but I have initialized in cpp files.
Other object are deleted in ~QWidget method using this statement

object->deleteLater

So, I navegate between Qwidgets using this statement

this->close();
frmCancella *can = new frmCancella();
can->showNormal();

frmCancella is my QWidget.

Sometimes when i navigate between QWidget, my application lost QWidget background image and later my application crashes.

I receive a message box that informe me about a stack overflow.

I don't know which component causes the problem, is there a method to understand where is the problem?

please help me
marrak

[danhicksbyron]

Well, if you say
this ->setAttribute(Qt::WA_DeleteOnClose,true);

and then say
this ->close();

you've kinda sucked all the oxygen out of the room.

"this" will become a "dangling pointer" and any further references to members of "this" object will be touching random bytes in storage.

I've never found it necessary to use DeleteOnClose or deleteLater. Normal use of the parenting mechanism takes care of 98% of storage management in Qt.

[giu_sca]

maybe i'm not clear in my explanation.

I had set "setAttribute(Qt::WA_DeleteOnClose,true);"

for each object into my QWidget, not on "this"

obj1->setAttribute(Qt::WA_DeleteOnClose,true);
obj2->setAttribute(Qt::WA_DeleteOnClose,true);
and so on

when i call another QWidget I use QWidget->close();

Initially i haven't used any "setAttribute(Qt::WA_DeleteOnClose,true); " statement, but i retrieve error memory message and the application crashes.

I'm walking alone in the dark.
^__^

[danhicksbyron]

You said you navigate between widgets using

this->close();
frmCancella *can = new frmCancella();
can->showNormal();

If the widget you're in when you do that has the DeleteOnClose attribute then it's going to go poof and leave you standing in midair.

[giu_sca]

sorry, but i haven't understood what you mean

[danhicksbyron]

Then I can't help you.

[giu_sca]

thanks a lot