[SOLVED] QTextEdit + Singleton = Memleak?

[Adelost]

I am using Qt 4.8.4 and if I make a singleton out of a QMainWindow and assign a QTextEdit, I get a huge memory leak. Any ideas?

@class Window : public QMainWindow
{
Q_OBJECT

private:
Window()
{
QTextEdit* textEdit = new QTextEdit(this);
this->setCentralWidget(textEdit);
textEdit->setPlainText(
"\n"
" INITIALIZING\n"
"\n"
" ~-_ Steamin'\n"
" -~ Hot\n"
" c|| COFFEE\n"
"");
}

public:
static Window* instance()
{
static Window instance;
return &instance;
}
};@

EDIT
Found a way to solve it! If I swap my lazy singleton to an ordinary singleton, things will work out.
@Window* instance()
{
// NOTE: "s_instance" is a static member variable
if(!s_instance)
s_instance = new Window();

return s_instance;
}@

[DerManu]

How do you know you get a huge memory leak? (Do you mean on termination of your program? Technically that's not a memory leak, more of a moral thing...)

[Adelost]

I tested it with Qt 5.0.2 as well, same result.

[quote author="DerManu" date="1368224963"](Do you mean on termination of your program?)[/quote] Yes during termination. Still feels quite bad thought.

My main looks like this:
@int main(int argc, char *argv[])
{
// Detect memory leaks
#if defined(DEBUG) | defined(_DEBUG)
_CrtSetDbgFlag( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );
#endif

// Create window
QApplication a(argc, argv);
Window* w = Window::instance();
w->show();

return a.exec();

}@

Haven't counted, but the memleak seems rather huge.
!http://i.imgur.com/gEnd0Tb.png(Memory leak QTextEdit.)!

[DerManu]

[quote author="Adelost" date="1368225736"]Yes during termination. Still feels quite bad thought.[/quote] Yes, you should feel a little dirty, that's okay.

Just a guess: Delete the singleton memory in a controlled fashion before QApplication goes out of scope. Or try hard to get rid of the singleton, in case you haven't done that yet.

[Adelost]

QTextEdit really doesn't like singletons it seems. Even if I delete the Widget manually still memleak. Gives me the creeps.
@Window()
{
QTextEdit* textEdit = new QTextEdit();
delete textEdit; // Deletes widget

// Still memleak, hmm...
}@

The only widget affected so far seem to be QTextEdit and QPlainTextEdit, ordinary widgets seems to work fine.

[Adelost]

Found a way to solve it! If I swap my lazy singleton to an ordinary singleton, things will work out.

@Window* instance()
{
if(!s_instance)
s_instance = new Window();

return s_instance;
}@