UniqueId.hpp

// Note: Experimental code, probably not production useful!

// Get a unique identifier based on the type, without modifying the type
// This will be unique for the runtime of the program, but is based on execution
// order, so it will possibly change the next time the program runs.
// Don't serialize it!

using UniqueIdType = uint64_t;

struct UniqueIdBase
{
  inline static UniqueIdType globalId = 0;
};

template <typename T>
struct UniqueId : public UniqueIdBase
{
  const static UniqueIdType Id()
  {
    const static UniqueIdType localId = ++UniqueIdBase::globalId;
    return localId;
  }
};

template <typename T>
UniqueIdType GetUniqueId()
{
  return UniqueId<T>::Id();
}

// Examples (these are the same):
// UniqueIdType id = GetUniqueId<int>();
// id = UniqueId<int>::Id();