Re: [Boost-build] How to get Boost build to embed install path into library

From: Jonathan Biggar (jon_at_[hidden])
Date: 2008-07-23 10:41:24

Jurko Gospodnetić wrote:
>   Hi Jonathan.
> 
>> I need to embed a path generated from the install prefix into my 
>> library so it can find files at runtime.  This isn't hard to do, since 
>> I can use a <conditional> requirement to generate 
>> <cxx-flags>-DMYPATH=... from <install-default-prefix>, but here's the 
>> problem.  If the user uses bjam to build the library, and then calls 
>> bjam later and changes <install-default-prefix>, how do I get the 
>> library to rebuild with the new -D option?
> 
>   My suggestion is to define a new composite, non-incidental feature.
> 
>   However this is not supported for 'free' features that take 'any text' 
> as their value (because Boost Build currently encodes used properties 
> that affect the build as path to the built target and free feature 
> values would mess up that path). You would need to define a list of 
> possible tag values and then convert them to exact paths inside your 
> build script.

The last part is a problem, since the idea is to allow the user to build 
the library and install it wherever he likes, which isn't compatible 
with a preset list of feature values.

But I wonder if it's possible to declare the feature and then use 
feature.extend to add the value I need on the fly (derived by converting 
'/' to '-' from the user provided install path).  Or even simpler, just 
calculate the right value up front before declaring the feature.

I'll have to experiment and see if I can make that work.

-- 
Jon Biggar
Floorboard Software
jon_at_[hidden]
jon_at_[hidden]