Re: [Boost-build] question(s) about bjam code IV

Subject: Re: [Boost-build] question(s) about bjam code IV
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2017-10-27 17:26:19

AMDG

On 10/26/2017 09:26 PM, Stefan Seefeld via Boost-build wrote:
> 
> now I'm looking into target-specific variables. I have added a few callbacks to 
> bjam to be able to set and query target-specific variables at different stages 
> of the build.
> 
> I'm a bit puzzled right now, as the variables I set earlier are no longer 
> visible at some later point. It seems this is related to the various 
> "pushsettings" / "popsettings" etc. invocations that happen throughout the bjam 
> code.
> 

  This could be because the code is cheating slightly.
pushsettings moves the target variables into the
module (instead of copying).  We can get away with
this because the code between pushsettings and popsettings
never accesses the target variables.  You might need
to make a copy with copysettings.

> Could you please briefly explain what those do, and why they are needed ? I'm 
> not using modules, i.e. everything I do happens in the context of the "root 
> module". Do I still need to push and pop settings ?
> 

Any place with push and pop settings in make/make1 is
because the code needs to access a target local variable.
There are several special variables (SEARCH, LOCATE, HDRSCAN,
__ACTION_RULE__, etc) that can be target specific, in
addition to any variables named in the ACTION.

In Christ,
Steven Watanabe