[Boost-build] Using target alternatives

Subject: [Boost-build] Using target alternatives
From: Phil Bass (Phil.Bass_at_[hidden])
Date: 2008-09-12 05:35:54

I'm trying to use target alternatives to select one of two source files 
based on the version of the gcc toolset, but I just get "No best 
alternative" errors. The toolset versions are 1) the default version of 
gcc for the host machine (Intel X86) and 2) a cross-compiler for a 
PowerPC-based target.

My user-config.jam contains:

   using gcc : x86 : g++ ;       # X86     version
   using gcc : ppc : gcc-ppc ;   # PowerPC version

And my Jamfile contains:

   obj Stub_Types_obj : Stub_Types_i386.cpp : <toolset>gcc-x86 ;
   obj Stub_Types_obj : Stub_Types_ppc.cpp  : <toolset>gcc-ppc ;

I've tried the following command lines:

   bjam -n Stub_Types_obj
   bjam -n Stub_Types_obj toolset=gcc
   bjam -n Stub_Types_obj toolset=gcc-x86
   bjam -n Stub_Types_obj toolset=gcc-ppc

They all produce:

   error: No best alternative for ./Stub_Types_obj
       next alternative: required properties: <toolset>gcc-x86
           not matched
       next alternative: required properties: <toolset>gcc-ppc
           not matched

So I have two questions. First, is it possible to select by toolset 
version? (I haven't been able to find anything in the docs on this.) 
And, second, what should I be doing to create an object file from one of 
two source files depending on the selected toolset/version?

-- 
Phil Bass (pab_at_[hidden])
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