Re: [boost] [release] Boost 1.66.0 Beta 1 Release Candidate 1

Subject: Re: [boost] [release] Boost 1.66.0 Beta 1 Release Candidate 1
From: Stefan Seefeld (stefan_at_[hidden])
Date: 2017-12-09 03:00:18

Hi Steven,

On 08.12.2017 21:52, Steven Watanabe via Boost wrote:
> AMDG
>
> On 12/08/2017 07:36 PM, Stefan Seefeld via Boost wrote:
>> On 08.12.2017 21:32, Tom Kent via Boost wrote:
>>> That sounds tricky.
>>>
>>> Does that mean that I'd need to modify my user-config.jam file between the
>>> two builds? (I.e. only have one version of python in there at a time?)
>> I believe so, yes (though would prefer someone like Steven or Rene as
>> the real experts to confirm the whole issue, as I may miss something).
>>
>   I'm not really familiar with the python toolset,
> but user-config.jam can contain arbitrary code,
> so, if there isn't a better solution, you can
> fall back on something like this:
>
> # Adjust the build paths when python3 is in use.
> # Note: This applies to all targets, even those
> # unrelated to python, so it's probably a bad idea
> # to use the --use-python3 option for building anything
> # other than Boost.Python.
> import feature ;
> feature.feature python-version : 3 : propagated optional ;
>
> import modules ;
> import toolset ;
> # Allow command line switching
> if --use-python3 in [ modules.peek : ARGV ]
> {
>   project : requirements <python-version>3 ;
>   using python : 3.xx : ... ;
> }
> else
> {
>   using python : 2.xx : ... ;
> }

Can you elaborate a bit on what this will achieve ? It seems this simply
means the same user-config.jam file can be reused for two `b2`
invocations (one with `--use-python3` and one without). But the build
logic would still need to be augmented to:

1) run `b2` as before
2) remove the build tree for Boost.Python, i.e. everything under
`bin.v2/libs/python`
3) rerun `b2`, this time with additional `--use-python3 --with-python`
arguments, to only rebuild Boost.Python, this time with Python3.
4) collect all binaries from the staging area during packaging.

Correct ?

Thanks,

Stefan

-- 
      ...ich hab' noch einen Koffer in Berlin...