Question about the interface classes

[Richard]

>
> a) EffectInterface inherits QObject, VolumeFaderEffectInterface  
> inherits
> QObject
> => obviously doesn't work because a VolumeFaderEffect  
> implementation would
> have to inherit both EffectInterface and VolumeFaderEffectInterface

Just wanted to shoot in, if I understand the problem correctly, that you
can solve this by using virtual base classes. If you e.g. specify:
class A;
class B : public virtual A
class C : public virtual A
class D : public B, public C

Then instances of D will only allocate one version of A.
Personally I feel that such a solution is messy, tough.... :)

-Ric