Using C++ Templates with C structs for introspection?

Question

I\'m doing some work in C++ for a company that has everything else written in C (using C isn\'t an option for me :( ). They have a number of data structures that are VERY simila

Answer 1

Yes, this isn't hard at all. Just put both an A and an Entry in a single object, and make the Entry a second-class citizen:

void setDefaultValues(Entry*); // You should be able to provide these.
struct Entry {
  int x;
  int y;
};
struct Indirect : public Entry { };
template struct EntryOr : public T, Indirect
{
  setDefaultValues(this);
};

// From C code
struct A {
  int x;
}

int main()
{
  EntryOr foo;
  foo.x = 5; // A::x
  std::cout << foo.x << foo.y; // Prints A::x and Entry::y
}

(Link)