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Subject: Re: [boost] [utility/value_init] boost::value_initialized<T> direct-initialized?
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2010-04-08 16:52:50

Niels Dekker wrote:
> Robert Stewart wrote:
> > Given that, I have to agree with Fernando that initialize is
> > merely a superset of value_initialize and can be harder to explain
> > unless it derives from value_initialize (even if it shares nothing
> > from the base and only makes clear that it is a superset).
> Thanks, Robert. But do you mean public inheritance? You know, I once
> considered having initialized<T> publicly derived from
> value_initialized<T>:
> But then I
> realized that it would imply that any "initialized" object is also a
> value_initialized object. While certainly an initialized
> object does not need to be value-initialized.

That is what I meant. A value_initialized object isn't stuck with its initialized value, is it? IOW, you can change the value later, at which point the object is no longer in a value-initialized state. Is that wrong? Is that a violation of the class' purpose? No. Likewise, an initialized instance allows for both forms of initialization; it is only concerned with some initialization having occurred. From value_initialized's standpoint, the object just has a value beyond what value-initialization would have given just as if an assignment had been done.

Rob Stewart robert.stewart_at_[hidden]
Software Engineer, Core Software using std::disclaimer;
Susquehanna International Group, LLP

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