Re: Practical Implementation of Private Inheritance

On Mar 21, 8:05 pm, sk.sma...@gmail.com wrote:


The usual case is when one is inheriting implementation, but not
interface. There are numerous examples in my own work, for
example: AssocArrayOf<> from HashTableImpl, FixedLengthAllocator<>
from AbstractFixedLengthAllocator, almost all of my ostream and
istream classes from StreambufWrapper. The first two cases
could almost be considered a pattern: a template class inherits
from a non-template base class which contains the
type-independent code. In the last, I use virtual inheritance
to ensure that the concerned sub-object is constructed first,
before the base class I really want to inherit from.

I also have a lot of classes which inherit privately from
UncopiableObject. Arguably, this should be public inheritance,
since the fact that they inherit from this class has a
significant impact on their public interface. But
UncopiableObject doesn't have a virtual destructor, and I don't
want people upcasting pointers to it.

In my application code (not present at my site), I also
occasionally make use of mixins, and will often use private
inheritance there.

For a more detailed discussion, and yet more examples, you might
try Barton and Nackman. They're pretty rigorous about it.

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