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Subject: Re: [Boost-build] Is there any way to preventBoost.Buildfromrecursively scanning header files for #includedirectives?
From: Johan Nilsson (r.johan.nilsson_at_[hidden])
Date: 2009-04-28 07:42:20


Lee Winter wrote:
> On Tue, Apr 28, 2009 at 3:16 AM, Johan Nilsson
> <r.johan.nilsson_at_[hidden]> wrote:
>> Lee Winter wrote:
>>>

[snip]

>>>
>>> Asa bebeficial side effect the collection of PSH files can also be
>>> useful for finding potential complexity reductions in the inclusion
>>> tree. Lakos mentions this as a potential performance improvement in
>>> his book about large scale software design.
>>
>> The Lakos book is one of my all-time favorites, but I can't remember
>> ever reading about PSH.
>
> It's not in there. The "this" I was referring to was the problem of
> complicated, duplicative, and outright unnecessary header file
> inclusion. Lakos describes how important it is to unsnarl the
> inclusion tree in order to avoid processing unnecessary and
> duplicative headers.
>
> PSH is just one way to make it easier to fix the real problem, which
> is bad header structure. It also reduces the build time by reducing
> the amount of scanning. But if you pay for the latter you have the
> info to accomplish the former as a cost-free side effect..

I was just about to say that this wasn't about bad header structure, and
that for large projects scanning/dependency checking will take time no
matter how well structured the source is ... but then I guess that wasn't
really your point.

Thanks / Johan


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