[Boost-build] How to use different toolsets for different files?

From: Jurko Gospodnetiæ (jurko.gospodnetic_at_[hidden])
Date: 2007-12-28 22:35:19

   Hi.

   I ran into a problem attempting to get one of our builds cleaned up 
using Boost Build.

   Project needs to build two sets of files - one generated using a 
toolset (e.g. msvc) and another generated using another one (e.g. a 
quickbook). Is it possible to get such a project to build from a build 
request (i.e. single command)?

   Here's a more detailed example.

   You have toolsets TA and TB. Toolset TA (think C++ compilers: msvc, 
gcc, intel...) can generate files of type A and toolset TB (think tools 
compiling internationalization messages, having nothing to do with what 
C++ compiler is used) can generate files of type B. I would like to run 
something like 'bjam TA TB' and get the following files built:

   bin/
     TA/
       /xxx.A
     TB/
       /yyy.B

   instead of getting an error that no viable generators have been found 
for building target xxx.A with toolset TB or target yyy.B with toolset TA.

   The only thing I can think of at the moment to achieve such an effect 
is to split the project into two separate projects - one building xxx.A 
and the other building yyy.B and then run their builds separately with 
different toolsets. But if I attempt to do that then I will again not be 
able to build both projects together from a shared master project.

   Perhaps I could hardcode it in the project to always use TA and TB 
for certain targets and ignore command-line options, but that would not 
work well as I would like to use different toolsets TA# of the same type 
for building xxx.A such as TA1, TA2, etc. and would not like the list of 
possible TA# toolsets hardcoded.

   Any ideas on how this should be handled?

   This could possibly be related to ticket #4 on trac 
(https://zigzag.cs.msu.su:7813/boost.build/ticket/4#preview).

   I guess the semantics I'd like here would be: build everything you 
can with all the toolsets I have given you, but do not complain if some 
of the targets can not be built using some of the specified toolsets 
(e.g attempting to generate documentation using a msvc toolset). It 
should still report errors for any explicitly requested targets that can 
not be built. If the current 'build all' semantics needs to be kept this 
could possibly be implemented by using some kind of an 'or' separator on 
the command-line between different toolsets telling Boost Build to build 
targets with at least one of the toolset values.

   Is there anything I'm missing that could go wrong if such semantics 
were used?

   Currently the project in question does this by not using an actual 
toolset for TB but defining its generators without any toolset 
requirements. That way Boost Build thinks targets built by 'TB' actually 
get built by TA and places all the targets under TA folders. However, 
this causes separate B targets to be built for each TA variation even 
though B targets do not depend on any of those variations.

   Best regards,
     Jurko Gospodnetiæ