Re: [boost] version conflicts: is there a solution?

Subject: Re: [boost] version conflicts: is there a solution?
From: Artyom (artyomtnk_at_[hidden])
Date: 2009-06-24 10:38:02

There are many problems and this is not as simple as you think.
Because if you have two versions of foo() defined in header
files they may be exported and... collide.

See: http://stackoverflow.com/questions/836875/

This problem is much more significant at UNIX platforms where
all symbols are exported by default.

Think of

boost_1.38

boost/foo.hpp  
namespace boost {
  int foo() { return 1; }
}


boost_1.39

boost/foo.hpp  
namespace boost {
  int foo() { return 1; }
}

Now the library includes this header from 1.38 and automatically
exports foo outside. Now, you use 1.39 and may
get different values of foo().

You may do simple tests and find how bad this is.

So... NO You can't use two versions of boost in same project
especially at ELF platforms.

......

I just what to remind that there is a script I had written 
that renames boost namespace and macros preventing namespace collisions
of two different versions of Boost.

http://lists.boost.org/Archives/boost/2009/05/151816.php

So take a look on it, and give feedback, so I would be able to
submit it officially to Boost.

Artyom

> Having the definitions separated into different translation
> units doesn't seem 
> to be enough to prevent ODR violations according to the
> standard.  It gives a 
> list of requirements for multiple definitions in different
> translation units 
> in section 3.2.5.
>