Consider the following standard CRTP example:
#include<iostream>
template<class Derived>
struct Base {
void f() { static_cast<Derived *>(this)->f(); }
void g() { static_cast<Derived *>(this)->g(); }
};
struct Foo : public Base<Foo> {
void f()
{
std::cout << 42 << std::endl; }
};
int main()
{
Foo foo;
foo.f(); // just OK
foo.g(); // this will stack overflow and segfault
}
If this was regular virtual inheritance I could have mark virtual f and g methods as pure like :
struct Base
{
virtual void f()= 0;
virtual void g()= 0;
};
and get a compile time error about Foo being abstract. But CRTP offers no such protection. Can I implement it somehow? Runtime check is acceptable too. I thought about comparing this-> f pointer with static_cast <Derived *> (this)->f, but didn't manage to make it work.
