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Subject: Re: [Boost-build] how to add include directories for compile but not for scan
From: George Georgiev (george.georgiev.sf_at_[hidden])
Date: 2012-04-21 22:19:53


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.

Is this the variable you had in mind?


On Sat, Apr 21, 2012 at 5:21 PM, George Georgiev
<george.georgiev.sf_at_[hidden]> wrote:
> Hi Steven,
>> Well, you could use cxxflags.
> You know better than me that handling all compilers specifics on your
> own is not a fun. cxxflags is not used everywhere where include is. I
> guess compile-include is not the best name, what I really implemented
> is non-scan-include.
>> Do you have numbers?
> As you probably already know I am working on generation project. I
> have dependencies on multiple 3rd party open source projects because I
> am generating code against various of them. What is more I actually
> validate the generated code not just against one but several versions
> of the same libraries.
> For example based on my usage of boost libraries on my machine reduces
> the scanning time with about 4s (per version). And I do not use a very
> big portion of boost.
> I have no time to create real benchmarking, but this is very useful
> improvement for my use case.
>> bjam -sHDRCACHE=.jamdeps
> This does not work for me. I even can not find HDRCACHE mentioned in
> the code at all. I find HDR_CACHE but it does not work too. Could you
> please point me to more detailed documentation of this feature?
> Thanks,
> George
> On Sat, Apr 21, 2012 at 4:49 PM, Steven Watanabe <watanabesj_at_[hidden]> wrote:
>> On 04/21/2012 02:57 PM, George Georgiev wrote:
>>> Hi,
>>> It took me less than 15 minutes to implement <compile-include> builtin
>>> feature myself (for the compilers I need) and I am not so familiar
>>> with Boost Build system.
>>> I found several discussions about this topic, other people asking for
>>> this or very similar feature.
>> Well, you could use cxxflags.
>>> Is there arguments why this should not be an officially supported
>>> feature?
>> It adds extra complexity.  In addition
>> to the implementation it would need
>> documentation and tests.  Every new feature
>> makes it harder for users to find what
>> they need.
>>> The time savings especially for incremental build are
>>> significant.
>> Do you have numbers?  Also, have you tried
>> using HDRCACHE?  (e.g. bjam -sHDRCACHE=.jamdeps
>> will cause the results of #include scanning
>> to be stored in a file called .jamdeps).
>>> And it looks to me extremely cheap for implementation and
>>> maintenance.
>> In Christ,
>> Steven Watanabe
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