Re: [boost] [core/noncopyable][test/boost::unit_test::singleton]massivetestfailures

Subject: Re: [boost] [core/noncopyable][test/boost::unit_test::singleton]massivetestfailures
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2014-08-21 12:21:25

On Thursday 21 August 2014 19:08:54 Peter Dimov wrote:
> Andrey Semashev wrote:
> > My point was that noncopyable should not impose any constraints on the
> > user's class beyond the ones needed. The fact that it did before C++11 is
> > not an advantage but the necessary evil people had to put up with.
> 
> What is your justification for this claim?

That's common sense, IMO. The side effects of noncopyable may be non-critical 
in most cases but not all. C++11 removes these side effects making noncopyable 
closer to what it actually should be.

> > Sure, but following that logic noncopyable shouldn't have existed in the
> > first place.
> 
> No, this does not follow (even though I agree that it shouldn't have existed
> :-). The fact that noncopyable only works for 99.4% of the uses does not
> 
> imply that it should not be provided.

...but we shouldn't make that 99.9%? I don't think I understand your point.

> > > Stated differently, were the changes driven by any kind of user demand?
> > 
> > Well, there was this ticket:
> > 
> > https://svn.boost.org/trac/boost/ticket/6578
> 
> Yes, I know. You'll note that it cites no reasons for the change and
> provides no examples of noncopyable's supposed inadequacy. It's just "C++11
> is shiny, let's make use of it!"

There are benefits from C++11 in noncopyable, it's not a change for nothing.