In a type trait, why do people use enum rather than static const for the value?

Question

For example, this is how I would write it, and it compiles and works just fine:

template struct is_pointer {
  static const bool valu         


        

Answer 1

Is it only because the static const variable uses a byte of memory, whereas the enum doesn't?

Yes, that's the reason.

static const bool value = true;

would occupy memory, while

enum { value = true };

doesn't.