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Subject: Re: [ub] type punning through congruent base class?
From: Tony Van Eerd (tvaneerd_at_[hidden])
Date: 2014-01-17 12:05:36


>
> Going back to constructor, what C++ has done is to automatically
> "bless" or perform the conceptial equivalent of access that stamps the
> effective type of the object. That also highlights why C++ is
> carefully in what can be done between the timeframe where storage is obtained and
> initialization is complete (e.g. the effective type/dynamic type is
> stamped.)
>

I think that is the way forward. After the constructor, the memory has been blessed/stamped/whatever.

The "object" returned from malloc is a "sequence of N unsigned char objects" (purposely quoting from 3.9's definition of 'object representation'). ie ready to be an object of whatever type, but not yet blessed beyond the base type unsigned char. (You could try to say it isn't even an array of unsigned char, but I don't think that will help.)

You then need to go at least some distance down the road of C's "effective type".

Tony
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