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Subject: Re: [boost] C++ announcements coming tomorrow
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2012-11-04 16:14:57

> Yes, it does. Taking aim at GCC instead, a huge amount of GNU code will
> not compile without --std=gnu++11 instead of --std=c++11. Even more of
> it won't compile without a POSIX environment--even ignoring the build
> system and autotools. The point is that, in many cases, portability
> should be accidental. I.e. with relatively few platform-specific
> exceptions (which should be isolated and generalized) programming is
> done against the abstract machine specified by the C++ standard. That's
> the compiler user's part of the contract. The compiler developer's part
> of the contract is to implement a compiler that compiles the language
> specified by the C++ standard.

I'd say you idealize too much. Surely, a lot of code can be written in
a platform-agnostic way, relying on the standard C++ only. But there is
a significant range of tasks that benefit from compiler extensions, and
that's not only OS-dependent things. Take manual vectorization for
instance, this is a CPU-specific thing which by definition cannot be
fixed in the standard. Generalized implementations are possible but
IMHO they will never be as efficient. Or multi-module interfaces - the
differences between OS implementations are too deep. Or for how long
the "long long int" type was an extension?

Look at extensions from another perspective. They are often a
playground to test new features that may eventually, after usage
experience is gathered, go into standard as a new feature. Only
extensions are available here and now and not in a few years when the
new std paper rolls out. This is pretty much like how it goes with libraries.

Don't get me wrong, I'm all for fully conforming compilers. But
objectively extensions are useful in some domains and eventually are a
good thing. You don't need them, you don't use them. But should you
need them, it's good they are there.

> Sure, lack of full support for the language and the presence of bugs are
> a huge problems. However, towards the end of 2012, I'm not particularly
> irrated by the current state of C++11 conformance. I am irrated by set
> in stone "won't fix" responses to bug reports and broken,
> mis-implemented features.

I agree, this disappoints a lot.

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