Re: [Boost-users] [TR1] How to say BOOST_USE_BOOST_TR1

Subject: Re: [Boost-users] [TR1] How to say BOOST_USE_BOOST_TR1
From: Markus Werle (numerical.simulation_at_[hidden])
Date: 2009-02-26 03:52:11

John Maddock <john <at> johnmaddock.co.uk> writes:

> 
> > I'd like to
> > #include <boost/tr1/*.hpp>
> > while at the same time state that I am *not*
> > interested in the compiler's TR1 implementation
> > (vc9 ...)
> >
> > Any MACRO BOST_HAS_NO_TR1 I missed?
> > The opposite (BOOST_HAS_TR1) exists.
> 
> Unfortunately you can't do that: the std::tr1 namespace has already been 
> polluted by the vendors implementation so we can't add ours in there as 
> well.

I have not included the TR1 headers of my compiler, so 
the pollution could be avoided. 
I expect boost/tr1/*.hpp to include the corresponding
compiler's header only if configured in that way.

> You can of course use boost::whatever directly, rather than 
> std::tr1::whatever.

Boost::whatevers are quite different from their TR1 sisters. 
(missing operator<< etc.) 
So I am really interested in the implications of those differences 
and want to have my code use std::* wherever possible. 
Boost contains a TR1 implementation, but unfortunately I face difficulties
to enfiorce its usage. This I find odd. 

Can we have the inclusion decision mechanisms be changed 
to something similar to:

#if (defined(BOOST_HAS_TR1_TUPLE) && !defined(BOOST_USE_BOOST_TR1_IMPL)) 
#  ifdef BOOST_HAS_INCLUDE_NEXT
#     include_next BOOST_TR1_HEADER(tuple)
#  else
#     include <boost/tr1/detail/config_all.hpp>
#     include BOOST_TR1_STD_HEADER(BOOST_TR1_PATH(tuple))
#  endif
#else
...

Or are we going to run into trouble because another std header might 
include the compiler's tr1 stuff again?

Markus