[Development] Why does QLabel::pixmap() return `const QPixmap*`?

Olivier Goffart olivier at woboq.com
Sun Nov 30 09:35:24 CET 2014

On Sunday 30 November 2014 06:37:11 Kevin Kofler wrote:
> Sze Howe Koh wrote:
> > I'm curious about the rationale behind this API design. I can't think
> > of any other Qt function that returns an implicitly-shared object by
> > pointer, so this seems inconsistent. e.g. QWidget::font() returns a
> > QFont by const-ref.
> Probably because the pointer can be null. C++ does not allow null
> references. (The compiler might let you get away with it, but in principle,
> it is not allowed.)

That's not the reason because you can return a null pixmap (QPixmap::isNull).

I don't know the reason. It was probably always like that 
( http://doc.qt.digia.com/2.3/qlabel.html#a1bd68 )

I know that moc has work around for that kind of property so if the getter 
returns a pointer, it can deference it 


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