David Abrahams wrote:
Howard Hinnant <hinnant@twcny.rr.com> writes:
I haven't dug into boost::is_pointer, but I'm guessing it involves a tentative binding to an ellipsis:
template <class U> static two test(...);
5.2.2p7 says that binding a non-POD class type to an ellipsis has undefined behavior. CodeWarrior's behavior in this context is to try to pass the type by value by using the type's copy constructor, which in this case is private, and thus triggers the access error.
Metrowerks::is_pointer has a much simpler implementation.
We should probably be forwarding to the metrowerks implementation on 9.4, where it's available. Failing that we can check is_class first and avoid the rest of the check in that case.
I must be missing something. The trivial implementation of is_pointer: template<class T> struct is_pointer: mpl::false_ {}; template<class T> struct is_pointer<T*>: mpl::true_ {}; should work on everything except MSVC 6/7, right? So why isn't it being used?