Re: [boost] [CMake] what to do now?

Subject: Re: [boost] [CMake] what to do now?
From: Peter Dimov (lists_at_[hidden])
Date: 2016-04-14 13:01:38

Paul Fultz II wrote:

> How does [bpm] know what files are associated with which library? It seems 
> more difficult to figure that out installing all the libraries together.

It cheats by assuming that library 'foo' is always in $BOOST_ROOT/libs/foo, 
so it just removes the whole directory.

In principle, it could re-download the package and remove only the files it 
contains, or it could record the files somewhere so it would know what to 
remove. But for Boost specifically, this doesn't seem worth the bother, 
because libraries are indeed contained in their libs/ subdirectories.

> Although, I don't think its unreasonable for a library to track its own 
> dependencies.

It may be reasonable... but for a Boost library it's not going to be very 
reliable. Since Boost library maintainers nearly always work against a full 
checkout, libraries can acquire (and sometimes drop) dependencies via a 
one-line edit and it's very easy to forget to record this in a 
'requirements' file.

bpm relies on dependency information generated by boostdep, but I need to 
rework it to scan on its own. The additional problem here is that if you 
don't have the full checkout you don't know what module contains which 
header. At some point in the future #include <boost/foo/bar.hpp> may always 
mean the foo library, but we're not there yet and it's not clear if we'll 
ever be.