Re: [Boost-build] Boost.Jam problem with dependant includes

From: Rene Rivera (grafikrobot_at_[hidden])
Date: 2006-09-28 10:40:01

Fabien Chêne wrote:
> After a discussion on fr.comp.lang.c++ about Boost.[Build/Jam], James
> Kanze pointed out that dependant macros do not cause dependencies.
> According to §16.2.4, the following code is legal C++, and Boost.Jam
> don't care about toto.hpp as a dependency :
> 
> cat toto.cpp
> //------------------------------
> #define DEPENDANT_INCLUDE( s ) #s
> #include DEPENDANT_INCLUDE( toto.hpp )
> //------------------------------

> I think the documentation is not clear enough about this problematic
> limitation (the problem is the same with classic Jam).

bjam (and jam) do not have a restriction as to what to consider a header 
include dependency. The restriction is in formulating a search criteria 
in Boost.Build (or Jambase, respectively). 
<http://engineering.meta-comm.com/resources/cs-win32_metacomm/doc/html/jam/language.html#jam.language.variables.builtins.hdrscan>

> Someone to confirm/infirm that ? If confirmed, is there a workaround ?

The work around is to define the HDRSCAN (and/or HDRPATTERN) accordingly 
for the kinds of headers you want to handle. Except for Boost.Build2 
which sets the HDRSCAN in a somewhat more complicated, but more modular, 
manner. Is it Boost.Build2 you are asking about?

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