Re: [jamboost] Default build improvement

From: David Abrahams (dave_at_[hidden])
Date: 2003-03-07 08:50:05

Vladimir Prus <ghost_at_[hidden]> writes:

> However, there's one use case I'm not sure about:
>
> d1/Jamfile reads
>
> exe main : main.cpp ../d2/l ;
>
> d2/Jamfile reads:
>
> lib l : l.cpp : : <optimization>space ;
>
> The intention is to build "l" with space optimization, unless asked
> otherwise. Is this important use case?

I think so. What's the problem?

> And what to do in this case:
>
> lib l : l.cpp : : <rtti>off ;
>
> If we respect default default build, and build request does not include 
> <rtti>off, we'll be using link-incompatible properties for building
> "l".

When? I thought the new rule was that the target's default value for
a given feature is used unless the user-supplied default-build
explicitly contradicts that (?)

> Probably the solution is to say that default-build cannot change
> link incompatible properties.

I don't see why you'd want to say that. Suppose you have a
"target-architecture" feature. That would be link-incompatible. You
might want to build for one architecture by default, but allow the
user to specify a different architecture.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com