From: David B. Held (dheld_at_[hidden])
Date: 2003-02-02 03:09:01
"David Abrahams" <dave_at_[hidden]> wrote in message
> If eating the cake means "not having to support unmanaged adoption",
> I don't think so ;-)
Well, I meant support both, of course. How hard would it be to create
the generic managed c'tor?
> > [...]
> > Now, the first that happens is that storage(p) attempts to take
> > ownership of p.
> p is an auto_ptr<U>&, so how is that ever going to happen?
Well, this was sloppy wording. I meant that storage will try to
take ownership of p's resource.
> > For default storage, this is a no-throw operation. Let's say we're
> > moving p into a counted pointer. Now ownership has to allocate
> > a count, and might throw in the process. If it does, we either have
> > to clean up p, or we have to stuff the toothpaste back into the
> > tube.
> Both highly imprecise notions; I don't know what either means for sure
> in this context.
Substitute 'p' for 'p's resource', and maybe it will make more sense.
> > I see that shared_ptr solves this by violating RAII.
> I don't know what this means either. RAII is not something you can
> "violate". It's a technique or idiom.
By "violate RAII", I mean, use default construction with a try-catch
block rather than the initializer list. The "RAII philosophy" that you've
been preaching for the last week is that you almost never need a catch
block if you use RAII properly.
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