[boost] Re: [build] relative vs absolute

From: Yuval Ronen (ronen_yuval_at_[hidden])
Date: 2005-05-22 04:57:58

"David Abrahams" <dave_at_[hidden]> wrote in message
news:ufywjju4b.fsf_at_boost-> > I've looked at the build system (i.e, Jam
files) and noticed that most of
> > time, the directories (include directories, link directories) are
specified
> > in absolute format - $(BOOST_ROOT)/whatever. However, not all of them
are
> > absolute. Some are relative - ../../../whatever. Other parts of the
Boost
> > tree, such as the html files, contain relative paths.
>
> Actually all the paths are relative.  $(BOOST_ROOT) expands to a
> relative path like ../../.. that is adjusted to a new appropriate
> value in each Jamfile.

I'd like to ask one more question, if possible.
How does it know how to expand $(BOOST_ROOT)?
If I'm standing in C:\libraries\boost_1_32_0\libs\python\test, for example,
how can it possibly know that "$(BOOST_ROOT)" is "../../.."? I can't think
of any algorithm that can reliably determine this. What am I missing?