Re: [boost] Re: dangerous_cast<>

From: Greg Colvin (Gregory.Colvin_at_[hidden])
Date: 2002-12-08 15:16:24

It may be time to post a question to c++std-core_at_research.att.com.

At 12:59 PM 12/8/2002, you wrote:

>--- Gabriel Dos Reis <gdr_at_[hidden]> wrote:
>
>> I'm not saying I hold the truth.  I'm offering my reading, just as others
>> are doing.
>
>Yeah, that's ok. I meant: it's unlikely that we can really find a
>quote from the standard that says the last word here. Maybe the intent
>was to make reinterpret_casting to void* implementation-defined, maybe
>the intent was to make it legal and equivalent to static_cast<void*>
>or, maybe, the intent was to disallow it, exactly because such a
>conversion is already possible with static_cast. I don't see enough
>evidence to say which of the three possibilities is right, but maybe
>it's just me. Frankly, I would ask to the writer. I remember that
>Steve Adamczyk is the author of the paragraph about static_cast.
>Probably he also wrote the one about reinterpret_cast and can say us
>what was the intent. If you drop him a mail, I will be glad to be
>cc-ed.
>
> 
>[...]
>> |   char * p = ...
>> |   reinterpret_cast<char*>(p)
>> | 
>> | is illegal, because the sentence above talks about conversion to *a
>> | different* type. And the conversions that are not listed cannot be done with
>> | reinterpret_cast).
>> 
>> Well, some of us, by the very nature of our jobs have to make sense of
>> some dispositions in the Standard.  Which means we've to _interpret_
>> some portions.  I don't know of any compiler that rejects the
>> above on the ground of what you're saying.  Do you? 
>
>No. But it is an interpretation. Probably, faced with such a doubt a
>compiler writer goes making a quick test with Comeau online and just
>concludes that his interpretation is "too literal" :-) As you say,
>this is "making sense" of a disposition. That shouldn't happen, the
>standard should always have a precise and unambiguous meaning, but it
>happens in practice. And, to be fair, we should say that if reading
>the standard is difficult writing it is even more so.
>
>Genny.
>
>
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