[Boost-build] How to get a default value for BOOST_BUILD_PATH ?

Subject: [Boost-build] How to get a default value for BOOST_BUILD_PATH ?
From: Samuel Debionne (samuel.debionne_at_[hidden])
Date: 2014-02-10 07:41:24

Hello,
I'm using Boost Build for my own project. Boost.Build is installed on my
system using "b2 install --prefix=/somewhere/bbv2".

This is working fine for the "hello" example.

For a specific project, I would like to add some custom rules to the
BBv2 path so I added a boost-build.jam at the root of the project :

MYPROJECT_ROOT = $(.boost-build-file:D) ;

BOOST_BUILD_PATH = $(DEFAULT_BOOST_BUILD_PATH) ;

if ! $(MYPROJECT_ROOT)/tools/build in $(BOOST_BUILD_PATH)
{
  BOOST_BUILD_PATH += $(MYPROJECT_ROOT)/tools/build ;
}

BOOST_BUILD = [ MATCH --boost-build=(.*) : $(ARGV) ] ;
BOOST_BUILD ?= $(BOOST_BUILD_PATH) ;
boost-build $(BOOST_BUILD) ;

My question is how should I define DEFAULT_BOOST_BUILD_PATH (something
like "../share/boost-build" relative to bjam executable path) ? Is there
such variable predefined ? If I could avoid defining it by hand that
would be great !

Samuel