Re: [Boost-build] Better caching of configure checks

Subject: Re: [Boost-build] Better caching of configure checks
From: Lars Viklund (zao_at_[hidden])
Date: 2012-10-14 09:10:07

On Sat, Oct 13, 2012 at 06:12:26PM -0700, Steven Watanabe wrote:
> AMDG
> 
> 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.

What implications will this have for end users out of the box?

What kind of things will this cache in a typical build of the Boost
project?

Will I have to constantly obliterate this file as I change toolsets and
options in the same build dir, or when I change something around with
optional dependencies like the MPI library, whether ICU exists or not,
and suchlike?

If this has any of the above implications, I hope it's violently
mentioned and documented on the site, lest a bajillion build scripts
will stop working.

> The cache is stored in a file called
> project-cache.jam which is created in
> the directory specified by --build-dir
> (if this flag is passed) or in the
> directory containing Jamroot.
> 
> The --reconfigure option causes the
> cache to be regenerated from scratch.
> 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.)
> 
> 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.

-- 
Lars Viklund | zao_at_[hidden]