[boost] Re: Interest in smart pointer with value semantics?

From: David B. Held (dheld_at_[hidden])
Date: 2004-01-03 03:18:22

"Thorsten Ottosen" <nesotto_at_[hidden]> wrote in message
news:bt5ip0$ge1$1_at_sea.gmane.org...
> [...]
> Having propagation of constness makes a lot of sense and
> would certainly make the smart pointers a lot smarter.

At first, I thought so too.  But then I thought about what raw pointers
do, and I decided that it was better to mimic the built-ins.  If you
always propagate constness, then you can't have a const ptr to a
non-const object.  Maybe that doesn't bother you, but perhaps there
is a scenario in which you want to be able to modify the pointee in
a function, but you don't want to accidentally reset() or release() the
pointer in that function.  Propagation of constness eliminates this
possibility.  The solution for deep-const is smart_ptr<T const>.  It's
not perfect, but I think it's the right thing to do.

> [...]
> smart_ptr< const T, deep_copy > ?

Yes, exactly.  That puts constness where it belongs.

Dave

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