[Development] Adoption of virtual_hook()

[Thiago Macieira]

On quarta-feira, 11 de abril de 2012 12.12.23, lars.knoll at nokia.com wrote:
> I was never a really big fan of adding lots of virtual_hook()'s to
> classes. vtable entries do come at a cost and in many cases it's not
> really required. I am certainly against blindly adding them to all our
> classes.

In KDE 3, we added virtual_hook() everywhere.

In KDE 4, we removed from all classes deriving from QObject. qt_metacall is 
our virtual hook.

For non-QObject classes which *already* have virtual tables, we should 
consider it. Fortunately, those classes are minority in Qt, we have very few 
of them.

And by consider, I don't mean "definitely use". Take QEvent, for example: it's 
virtual, but it has barely any virtual functions. It's unlikely we'll need a 
virtual_hook in it.

(In fact, QEvent is really bad: it's a copyable polymorphic class)
-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center
     Intel Sweden AB - Registration Number: 556189-6027
     Knarrarnäsgatan 15, 164 40 Kista, Stockholm, Sweden
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