How can I detect whether a type is a visible base of another type?

Question

If I do

struct A{};
struct C:private A{};

typedef char (&yes)[1];
typedef char (&no)[2];

template 
struct Host
{
 operato         


        

Answer 1

Do you need something that can be evaluated at runtime, or will a simple compile time error suffice?

struct A {};
struct B : private A {};

int main()
{
   B b;

   // gives error C2243: 'static_cast' : conversion from 'B *' to 'A &' exists, but is inaccessible
   A& a = static_cast(b);

   return 0;
}