c++member-pointers

Nested data member pointer - not possible?


The following reduced code sample does not do anything useful but two subsequent assignments to a data member pointer. The first assignment works, the second one gives a compiler error. Presumably because its to a nested member.

Question would be: Is it really just not possible to let a member pointer point to a nested member or am I missing any fancy syntax there?

struct Color {
    float Red;
    float Green;
    float Blue; };


struct Material {
    float Brightness;
    Color DiffuseColor; };


int main() {
    float Material::* ParamToAnimate;
    ParamToAnimate = &Material::Brightness;       // Ok
    ParamToAnimate = &Material::DiffuseColor.Red; // Error! *whimper*
    return 0; }

ATM I am working around by using byte offsets and a lot of casts. But that is ugly, I would better like to use those member pointers.

Yes, I know that question surely arised before (like nearly any question). Yes, I searched beforehand but found no satisfying answer.

Thanks for your time.


Solution

  • AFAIK, this is not possible. A pointer-to-member can only be formed by an expression of type &qualified_id, which is not your case.

    Vite Falcon's solution is probably the most appropriate.