Re: [Boost-build] Run target dependency on exe without getting transitive usage requirements

Subject: Re: [Boost-build] Run target dependency on exe without getting transitive usage requirements
From: Chambers, Matthew (matt.chambers42_at_[hidden])
Date: 2019-03-11 18:44:11

On 3/11/2019 1:41 PM, Steven Watanabe via Boost-build wrote:
> The only way to prevent usage-requirements from propagating
> upwards is to create a custom target class that filters them
> out.  In this particular case, you can probably work around it
> by building the run target's executable separately.
>
> run a.cpp ; -> exe a : a.cpp ; run a ;
How does this work? What prevents 'a' from running before 'a' is built?

> As Stefan pointed out, we have no good way to determine
> what should propagate and what should not, so we always
> propagate everything (with a few hard-coded exceptions. Grrrr.)
Seems like we this might require the opposite of <use>'s difference from <dependency>: something that makes something depend on something 
else being built first, but ignores all its requirements

Thanks,
-Matt