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From: David Abrahams (david.abrahams_at_[hidden])
Date: 2001-09-29 08:24:51

----- Original Message -----
From: "Eric Ford" <eford_at_[hidden]>

> I haven't been paying attention to the discussions about a boost build
> system for libraries requiring code not in header files. In principle
> that could generate a header file with constants such as these that
> were necessary for some functions. The only alternative I can see is
> a lot of ugly #ifdef's or code that will only compile with a deplate
> depth of significantly greater than 17. Using a build system to
> generate headers would be somewhat inelegant. On the plus side, it
> would introduce the least possible overhead, since the constants would
> just be constants (after the first compile) and not need to be
> calculated either at run time or at compile time. However, I'm not
> sure if this would be acceptable to the rest of the boost crew. I
> could understand some being very opposed to relying on machine
> generated header files.

There is already precedent for it. Various libraries, including the Python
and PREPROCESSOR libraries, include generated headers.

> Comments from the boost powers that be? Is this functionality that
> the boost build system could provide?

Sure, if somebody writes the generator program. Boost.Build already works
with lex and yacc / flex and bison.

> How far in the future before
> such a build system is functional? Ready to be included in the boost
> distribution?

Well, it's already functional and AFAIK in the distribution, but there are
lots of things still on the TODO list. My work on the build system is going
to be a bit slow in the immediate future while I seek employment.

  David Abrahams, C++ library designer for hire

        C++ Booster (
          email: david.abrahams_at_[hidden]

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