[Q] Boost-Build V2

18 Aug 2003

      Dear Listmembers,

since a few weeks I'm using boost within a development system
which should be changed towards operating system independence. 
As boost-buil V2 has a lot of nice features I wanted to base
the build process on it.  Unfortunatly it's very confusing 
to get all the information I need and sometimes it is not clear
to which boost-build version (v1 or v2) some documentation 
belongs to. I hope this list is the right place to ask some
questions about this.

I'm going to describe the my current setup first (which is
a little bit longish in order to cover all important points,
hopefully) and afterwards I'll explain the problems.

The scenario: We have some self-made class libraries which
depend on downloaded packages (one is boost). So I thought 
of using the (usage-)dependency features of boost-build v2 
for automatically using the right include paths and the 
according libraries. (I'm using milestone 6 of boost-build)

root
 | 
 + pkgs + boost_1_30_0
 |      |
 |      + log4cpp_0.3.4b + include
 |                       + lib
 |
 + mylib + include
 |       + src
 | 
 + myapps + testapp + src

The idea was to separate the information of which package versions to 
use and where libraries and include files reside. 

For this I put a Jamfile into 'pkgs' which consist of the following entries
(OS independence not included right now)

-------------------------------------------------------------------

project pkgs ;

BOOST   = boost_1_30_0 ;
LOG4CPP = log4cpp-0.3.4b ;

# system libraries
lib winsock : : <name>Ws2_32.lib ;
lib advapi  : : <name>Advapi32.lib ;

alias all : log4cpp boost ;
alias boost : : <include>$(BOOST) ;

lib log4cpp
    :
    : <file>$(LOG4CPP)/msvc6/log4cpp/Release/log4cpp.lib  <variant>release
    :
    : <library>winsock <library>advapi
    ;
lib log4cpp
    :
    : <file>$(LOG4CPP)/msvc6/log4cpp/Debug/log4cpp.lib <variant>debug
    :
    : <library>winsock <library>advapi
    ;
-------------------------------------------------------------------

and the Jamfile in 'root' (where project-root.jam and boost-build.jam 
resides) contains 

-------------------------------------------------------------------

project MyProject
    : default-build debug <link>static
    ;

use-project /pkgs : ./pkgs ;
use-project /MyLib: ./mylib ;

-------------------------------------------------------------------

The Jamfile in 'mylib' uses several of the libraries defined in 
'pkgs' 

-------------------------------------------------------------------
project MyLib
    : usage-requirements <include>./include
    : requirements       <include>./include
    : source-location ./src
    ;

LIBSRC =
    [ .. whatever ..]
    ;

lib MyLib  : $(LIBSRC) : : : <library>/pkgs//log4cpp ;
lib MyLib2 : $(LIBSRC) : : : <library>/pkgs//all ;

-------------------------------------------------------------------

and  the application 'testapp' depends on 'mylib'
-------------------------------------------------------------------
project testapp
    : requirements <library>/MyLib//MyLib
    : source-location ./src
    ;

exe test 
    : testapp.cpp
    ;

exe test2
    : testapp.cpp
    : 
    : <library>/MyLib//MyLib2
    ;
-------------------------------------------------------------------

Problems/Questions
==================
- I had to put a (empty) 'project-root.jam' file into 'pkgs'.
  Otherwise I get the error message:

    error: default build can be specified only in first alternative
    main target is  ../../../pkgs/log4cpp

  Any ideas why this happens?

-  the library dependcies for 'log4cpp' are correct and the 
   appropriate library is linked BUT the include depencies 
   are not used (neither for boost nor for log4cpp).
   I had to add the paths once more into the Jamfile in 'root'
   to make them available. After the changes the Jamfile looks 
   like this

-------------------------------------------------------------------
BOOST   = pkgs/boost_1_30_0 ;
LOG4CPP = pkgs/log4cpp-0.3.4b ;

project MyProject
    : default-build debug <link>static
    : requirements
      <include>$(BOOST)
      <include>$(LOG4CPP)/include
    ;

use-project /pkgs : ./pkgs ;
use-project /MyLib: ./mylib ;

-------------------------------------------------------------------

   This is not what I wanted because now the paths to the 
   package directies appear twice, once in root/Jamfile and once in
   root/pkgs/Jamfile.

Thanks you very much !

Best Regards,
Chris Drexler