Re: [Boost-build] Adding "on target" variables "on the fly"

Subject: Re: [Boost-build] Adding "on target" variables "on the fly"
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2017-06-17 14:24:02

AMDG

On 06/17/2017 05:21 AM, Stefan Seefeld via Boost-build wrote:
> <snip>
> Here is the use-case:
> 
> I'm trying to implement a config check that consists of this chain of
> actions:
> 
> 1) determine whether the given Python version has the "numpy" module
> installed, and if so, report the associated include path
> 
> 2) with that include path, try-compile a little app to make sure all
> compiler flags work.
> 
> The problem (in the original bjam logic) is that all "on target"
> variables had to be defined before the scheduler's "update" function
> (the "update_now" rule in Jam lingua) would be called. I.e., it isn't
> possible for one target action to add or modify variables used in
> another, unless the two were built by separate calls to the "update_now"
> rule.
> <snip>

Can't you do this with __ACTION_RULE__?
http://www.boost.org/build/doc/html/jam/language.html#jam.language.variables.builtins.actionrule

In Christ,
Steven Watanabe