Re: [Boost-build] Specifying define on command line

From: David Abrahams (dave_at_[hidden])
Date: 2007-08-05 17:07:53

on Sun Aug 05 2007, Vladimir Prus <ghost-AT-cs.msu.su> wrote:

> I see two solutions:
>
> 	1. Make 'free' features like 'define' and 'cflags' propagated. This
> 	will have undesirable effect that <define> set on some target
> 	will propagate to all dependencies.
> 	2. Make free features specified on the command like apply to
> 	all targets in the project located in ".", and any child project.
> 	The only concern I have about this approach is that it will
> 	still be impossible to specify define that will apply to all
> 	compilations. That is, if I have two projects A and B,
> 	in different directories with separate Jamroots, where A uses
> 	libraries from B, then:
>
> 		bjam define=FOO
>
> 	in A won't affect B.
>
> Anybody can comment on those alternative or propose better ones?

3. Free features on the command line apply globally.

3 is the simplest way to address the problem, and probably matches
most people's expectations.  I think 1 is the wrong way.  The command
line options are an expedient and blunt instrument for developers who
think they know what they're doing; I think they should be treated
altogether differently from build properties specified in Jamfiles,
which can be carefully tuned.

-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com
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