Re: Cost of dynamic_cast

From:
Ulrich Eckhardt <eckhardt@satorlaser.com>
Newsgroups:
microsoft.public.vc.language
Date:
Wed, 13 Sep 2006 18:01:55 +0200
Message-ID:
<jkmlt3-vkr.ln1@satorlaser.homedns.org>
Ole Nielsby wrote:

Tom Widmer [VC++ MVP] wrote:

[...] On Windows, [...] the same class [...] might be in the .exe
and in [...] .dlls. As a result, dynamic_cast actually performs
string comparisons [...]

Linux doesn't have this problem [...]


This explains it. The string comparisons was what really baffled me.


Nothing to do with Linux, this is compiler-specific and GCC will probably do
just pointer comparisons on win32, too, just as any other compiler might.

The better way is to avoid designs that rely heavily on dynamic_cast. Why
do you need to dynamic_cast?


For interpreting a dynamically typed programming language.


Even a dynamically typed language interpreter doesn't create new C++ types
at runtime... I'm still curious why you need so many dynamic_casts. Also, I
forgot to mention that in my last post, you might consider posting to
comp.lang.c++.moderated, which generally gives much better outcome for
non-VC specific problems.

happy hacking

Uli

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