"Robert Ramey" <ramey@rrsd.com> writes:

I have the following little test program

#include <boost/static_assert.hpp> #include <boost/type_traits/is_polymorphic.hpp>

struct vbase { };

struct derived : public virtual vbase { };

// VC 7.1, borland 5.51 and Commeau trap here (gcc 3.2 doesn't trap here!) BOOST_STATIC_ASSERT(boost::is_polymorphic<derived>::value);

I think this is a problem and I doubt we can implement an is_polymorphic that does the right thing on gcc for this case.

// everything including gcc traps here ! BOOST_STATIC_ASSERT(boost::is_polymorphic<vbase>::value);

One would expect it to. vbase is not polymorphic!

int main(int argc, char *argv[]) { }

This suggests to me that is_polymorphic returns true for a class derived virtually from a base class under the gcc compiler even though the base class has no virtual function!

Seems so. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com