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Subject: Re: [boost] [Booster] Or boost is useless for library developers
From: Christian Holmquist (c.holmquist_at_[hidden])
Date: 2010-05-20 11:16:03

On 19 May 2010 18:54, David Abrahams <dave_at_[hidden]> wrote:

> At Wed, 19 May 2010 19:49:33 +0000 (UTC),
> Gennadiy Rozental wrote:
> >
> > Templates do lead to the larger code size and larger compilation
> > time. You can hardly argue with that.
> I certainly can. It all depends how they are used. If you use other
> means of polymorphism (e.g. virtual functions) on a fine-grained
> level, the cost in code size of dispatching to trivial functions that
> could otherwise be inlined can easily overwhelm “template code bloat.”
In that conversation you say that:
"As far as I know, getting everything just right involves walking the
line between static and dynamic polymorphism, compiling some generic
things down to object code, and leaving others to be "instantiated"

I think nobody can object to that, and the discussion/problem is about where
to draw the line. But I could have misunderstood =)

What I find strange is that Boost librariy developers, in general, seems to
agree that template bloat is of no or little concern, #include dependencies
is of no or little concern, and compilation time for end-user is of
absolutely no concern. A few developers bothers with this, and their work I
appreciate very much.
The one -big- concern is that every piece of code is visible so that it can
be inlined in every compilation unit. For performance.
Why so?
Performance is a very complicated matter as everybody knows, and inlining is
no holy grail. Performance is improved by analysis of a running program and
taking proper action,
but the more time I sit around waiting for compilation to finish after minor
modification the less time I can spend on such activities.

It would, I think, be beneficial to Boost if the standpoint on header only
was less strict, and that ideas about hiding implementation details in .cpp
files were not looked upon as craziness. =)

Looking forward to a wrapped up Boost btw, if Booster ever comes to life!


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