[boost] New config macro : BOOST_CXX0X_REFERENCE_COLLAPSING

From: AlisdairM (alisdair.meredith_at_[hidden])
Date: 2007-01-02 18:39:10

Recently there was some discussion about adding config support for
C++0x features.

The attached test would pass for compilers implementing Core Issue 106
- reference collapsing.

There are a couple of associated issues:

  Is this our preferred naming convention?
  Does the config generating script need updating to support it?
  Which compilers already implement the feature?
  Can any existing libraries put the detected feature to use?

For reference, here is the source for the test case extracted from the
attached file:

template < typename T >
struct test_holder
{
    typedef T & type;
};

typedef test_holder< int & >::type wrap_test;

This will be a compile time failure on platforms that do not support
the feature, but it must be actively enabled on a per-compiler basis in
the compiler config files.

-- 
AlisdairM