"David B. Held" <[EMAIL PROTECTED]> writes:
> I suppose we could do something like this:
>
> void scalar_storage::acquire(stored_type const& p)
> {
> pointee_ = p;
> }
>
> template <typename U>
> void ref_counted::acquire(U const& p)
> {
> }
>
> template <typename U>
> smart_ptr(U const& p)
> {
> try
> {
> storage_policy::acquire(p);
> ownership_policy::aquire(p);
> checking_policy::on_init(get_impl(*this));
> }
> catch (...)
> {
> storage_policy::destroy();
> throw;
> }
> }
>
> Ultimately, it's only slightly less efficient than the initializer list
> form, and
> now doesn't leak p when someone passes 'new X'.
It sure does if any of the bases or members of smart_ptr throws from
its constructor.
> Orthogonality is preserved, and angels from on high sing Hallelujah
> (ok, maybe the last part is stretching it). Taking ownership
> probably should be a separate step from construction anyway.
I dunno. Acquiring ownership at construction time is a key part of
the "one true meaning" of RAII (not the accepted meaning, which has
come to be "deallocating resources in destructors" -- a concept having
nothing to do with acquisition _or_ initialization). There's a good
reason for this, since it avoids the problem of leaking when a
constructor throws.
--
David Abrahams
[EMAIL PROTECTED] * http://www.boost-consulting.com
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