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Subject: Re: [Boost-build] how to add include directories for compile but not for scan
From: Nogradi, Chris (Chris.Nogradi_at_[hidden])
Date: 2012-04-23 14:57:28

Isn't time still wasted searching for the missing system includes in the normal include paths?


-----Original Message-----
From: boost-build-bounces_at_[hidden] [mailto:boost-build-bounces_at_[hidden]] On Behalf Of George Georgiev
Sent: Saturday, April 21, 2012 11:04 PM
To: steven_at_[hidden]; Boost.Build developer's and user's list
Subject: Re: [Boost-build] how to add include directories for compile but not for scan

> How much is the total no-op build time?
for a build against one version of boost it is ~7s with all includes
scanned and it is reduced to ~3s when the boost is no-scan-include.

When the change is small (a few cpp files) it basically reduces the
time for the build with ~50%

The proportion is not so significant with other libraries. The only
other beast is QT. There the improvement is insignificantly better.

It does not seem so match, but once the feature is implemented it is a
pure improvement without any trade off.

Thank you for looking into this.


On Sat, Apr 21, 2012 at 8:33 PM, Steven Watanabe <watanabesj_at_[hidden]> wrote:
> On 04/21/2012 07:19 PM, George Georgiev wrote:
>> Hi,
>> I found it I believe. At least if I specify HCACHEFILE bjam generates
>> a file that looks like enumeration of headers.
>> Unfortunately, this has zero effect over the performance. The
>> performance is so the same, I am not sure this file is actually used
>> in the next build process at all.
> It's possible that it doesn't work correctly.
> I haven't tested it much. Anyway, at some
> point after 1.50 I'll look into your
> optimization. Right now, any work I do
> on Boost.Build is targeted at making sure
> all the current changes get into 1.50.
>> Is this the variable you had in mind?
> Yep.
> In Christ,
> Steven Watanabe
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