Re: [Boost-build] Target paths idea

From: Jurko Gospodnetić (jurko.gospodnetic_at_[hidden])
Date: 2007-12-03 05:10:46

u  Hi.

> Or you could just not represent the feature when it has its default
> value, just as feature relevance worked in BBv1.

   That is the way BBv2 already works and that is not what I meant.

   I meant allowing a project to explicitly specify that it will use 
only one value for a given feature and so no matter how the feature is 
defined (whether it has a default value or not, whether its build folder 
is created when its default value is used, whether the specified value 
is the feature's default value or not...) the build system will not 
create a folder for that feature or allow the project to be built using 
a different feature value.

   Here's an example:

   'runtime-link' feature has 'dynamic' set as its default value and I 
do believe the 'runtime-link-dynamic' folder is never created. However 
we have projects (many in fact) that use static 'runtime-link' feature 
value, and they must never use dynamically linked runtime libraries. For 
those projects, the build folder 'runtime-link-static' created by Boost 
Build is redundant and could be skipped.

   My suggestion would allow such projects to specify such 'fixed' 
feature values which would allow them to:

     1. Not create such unnecessary build folders, thus reducing the 
build folder path length and making the folder path easier to read when 
in the context of that project.

     2. Create subprojects that can only be built with one feature value 
and have them ignored/not-built if the main project is built with a 
different feature value (useful e.g. if you have client/admin build 
types for the master project and some sub-projects are products that 
make sense only in admin mode builds and you do not want their client 
mode builds to be even attempted).

   Hope I have not managed to mess up the explanation again... :-))

   Best regards,
     Jurko Gospodnetić