Shibboleth Developers

[Derek Atkins <>]

So in other words I should be able to safely dynamic_cast<> any
of my own objects, but I may need to work around times where I
cast a SAML or Shib object.  What about when I use a saml object's
clone() method -- is that safe to dynamic_cast<> back to itself?

-derek

Scott Cantor 
<>
 writes:

> > This implies that all uses of dynamic_cast<> are subject to 
> > this bug, eh?  That means I need to fix my code as well.
> 
> I think it's probably possible to use it in some contexts, mostly if
> you're within the same body of code that built the object and would have
> implemented the RTTI supporting code. It also appears to be safe in
> executables that are totally linked in advance.
> 
> It seems to come up more in cases where you write one library that casts
> an object implemented in a second library, so any casting of SAML
> objects down would most likely break.
> 
> > Where is it safe and where is it not safe to use C-casts?
> 
> Any time you really know the pointer's real type, you're safe, barring
> unforeseen errors. OTOH, if for example you have a collection of common
> objects (say, oh, an assertion's statements) with no way to know what
> type of statement each one is, there's no possible way to make it safe.
> You simply act like you're in C, and you stick additional functions or
> data in to tell you what the story is. That's all dynamic_cast and
> typeinfo are anyway, but the compiler does it for you.
> 
> -- Scott
> 

-- 
       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
       

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