[boost] Re: compressed_pair requirements?

From: Eric Niebler (eric_at_[hidden])
Date: 2005-06-03 22:51:47

Howard Hinnant wrote:
> 
> The scary part is that we do so many useful things these days by 
> tentatively passing non-POD's past an ellipses, though only at compile 
> time, never at run time.  But the compiler is not making that distinction.
> 
> This is a big problem, and I suspect it will need to be addressed at the 
> standards level.  I don't have a solution yet.
> 

The solution is to not pass non-PODs through ellipses, of course. ;-)

   double is_mem_fun_ptr_tester(...);

   template<typename Class, typename Ret>
   char is_mem_fun_ptr_tester(Ret (Class::**)());

   template<typename T>
   struct is_member_function_pointer
   {
     BOOST_STATIC_CONSTANT(bool,
       value = 1==sizeof(is_mem_fun_ptr_tester(static_cast<T*>(0))));
   };

   typedef char test1[
     is_member_function_pointer<void (dummy::*)()>::value ];
   typedef char test2[
     !is_member_function_pointer<dummy>::value ];

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com