Casting one C structure into another

Question

I have two identical (but differently named) C structures:

typedef struct {
      double x;
      double y;
      double z;
} CMAcceleration;


typedef struc         


        

Answer 1

Another version of the utility function making use of C99:

static inline struct Vector3d AccelerationToVector(struct CMAcceleration In)
{
    return (struct Vector3d){In.x, In.y, In.z};
}

With the compiler optimization turned up (e.g., -Os), this should turn into absolutely no object code when invoked.