Re: Reinterpret cast and CRTP

From:
peter koch larsen <peter.koch.larsen@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Sun, 17 Jan 2010 07:18:58 CST
Message-ID:
<622c123b-4446-42cc-98e8-ffedead8a5e7@j14g2000yqm.googlegroups.com>
On 13 Jan., 14:35, Ulrich Eckhardt <eckha...@satorlaser.com> wrote:

peter koch larsen wrote:

On 12 Jan., 05:33, pfultz2 <pful...@yahoo.com> wrote:

When i use the curiously recurring template pattern, do i need to use
the reinterpret_cast to get the derived class or do i use the
static_cast?

[...]

Im under the assumption that a static cast wouldnt work since the
derived class is not known at compile time. And if it werent then
would a reinterpret_cast be safe, if it were always used this way??


The best would be to use a dynamic_cast. If this is not available to
you, you should use a static_cast.


In the given example it is not available because MyClass is not polymorphic,
it doesn't have any virtual functions, hence no RTTI and no dynamic cast.
That said, I would actually accept dynamic_cast for checking in diagnostic
mode, but that's all.


That is correct and what I meant with a dynamic_cast being available.
Apart from that, I overlooked that the cast happened in a "safe"
place, assuming that Base is always a base of Derived.
What I don't understand is your comment to your own post. There is no
polymorphism and in the actual case dynamic_cast will not be
available.

/Peter

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