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Subject: Re: [Boost-build] Better caching of configure checks
From: Jürgen Hunold (jhunold_at_[hidden])
Date: 2012-10-15 16:41:58

Hi Steven,

On Saturday, 13. October 2012 18:12:26 Steven Watanabe wrote:
> The attached patch implements a cache that
> stores the results of all configure checks.
> This reduces the no-op build time
> for msvc-11.0 in BOOST_ROOT with no extra
> options from 8 seconds to 3 seconds for me.

Nice work. This really speeds things up.

> The --reconfigure option causes the
> cache to be regenerated from scratch.

This needs to be documented very well. I wonder if "--configure" would be more
consistent. But that might be bikeshedding from my side ;-)

Is there an option to force reconfiguration or disabling the cache from site-
config.jam or user-config.jam? This might come handy when setting up 3rdparty
libraries. This requires some experimenting and dirty caches can get in the
way *fast*. This is what is annoying with CMake...

> I think that passing -a should also clear
> the cache, but I put that off, since
> the engine doesn't expose most of its
> flags to Jam code. (I'd rather not
> duplicate the option parsing logic
> either.)

Yes, this can be refactored later.

> I've tested this with msvc-9.0express,
> msvc-10.0express, and msvc-11.0 on
> Windows 7 and with gcc-4.5.1, gcc-4.7.2,
> and clang on linux.
> Any thoughts on this before I commit it?

I'd like this to be mentionened *at least* in "b2 --help" output somewhere at
the top. And of course in the getting started guide(s).



* Dipl.-Math. Jürgen Hunold  ! 
* voice: ++49 4257 300       ! Fährstraße 1
* fax  : ++49 4257 300       ! 31609 Balge/Sebbenhausen
*             ! Germany

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