Re: [Boost-users] [mpl] Is it possible to mpl_assert dependingonthe derivation of a class

Hughes, James wrote:

Just a quick addendum to this. I tried out a combination of the two - using a BOOST_STATIC_ASSERT((boost::is_base_of >::value)) inside the do_it function described above, and found what I thought was odd behaviour with is_base_of.

The following excerpt shows the behaviour

class A {};

class B : public A {};

typedef A C;

BOOST_STATIC_ASSERT((boost::is_base_of >::value)) // this passes

BOOST_STATIC_ASSERT((boost::is_base_of >::value)) // this fails

I would expect both to pass, as is_base_of should return true when both parameters are the same, and I thought that typedef did make classes the same/equivalent

http://www.boost.org/doc/html/boost_typetraits/reference.html#boost_typetrai...

Is there something I am missing about typedef? Or is boost::is_base_of unable to handles the aliasing?

James

Hi James, I tried this with GCC 4.2 and 3.4.6 under Linux. It passes for both cases. So it might be your compiler, which is doing something wrong. Martin