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: Steven Watanabe (watanabesj_at_[hidden])
Date: 2017-12-09 03:12:48

AMDG

On 12/08/2017 08:00 PM, Stefan Seefeld via Boost wrote:
> On 08.12.2017 21:52, Steven Watanabe via Boost wrote:
>> <snip>
>> 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 ?
> 

  Step (2) is not necessary.  python-version is specifically
to avoid this step, by forcing the python3 build to
use a different build directory.

In Christ,
Steven Watanabe