Re: [boost] [Booster] Or boost is useless for library developers

Subject: Re: [boost] [Booster] Or boost is useless for library developers
From: Gennadiy Rozental (rogeeff_at_[hidden])
Date: 2010-05-20 16:57:07

David Abrahams <dave <at> boostpro.com> writes:

> 
> At Thu, 20 May 2010 10:16:03 -0500,
> Christian Holmquist wrote:
> > 
> > On 19 May 2010 18:54, David Abrahams <dave <at> boostpro.com> 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.”
> > >
> > > http://www.cpptalk.net/image-vp103267.html#103267

I was not trying to proof a theorem, but general trend (and my experience as
well) is that template based solution in comparison with *semantically*
identical solution based on runtime polymorphism usually takes longer to compile
and produce larger code. Fun fact: in company I work for, the fear of code bloat
and longer compilation/link time (admittedly based on some bad experience) lead
to almost every instance of vector and shared_ptr to be explicitly instantiated.
Hoverer much I dislike it I can't tell 200 developers "it's ugly - let's add 10
min to your compilation/link time". 

> > What I find strange is that Boost librariy developers, in general, seems to
> > agree that template bloat is of no or little concern, 
> 
> I don't.  You can see that from the design of Boost.Python, which
> assiduously tries to get everything that can be static into the
> library binary.

I myself is very heavy Boost.Python user. And in this case in spite of the fact
that my code is probably longest to compile, I believe that for the most part
Boost.Python got this balance right. Not everyone in a team agree with me though.

Gennadiy