[G_Morgan]

Simply enough I'm writing a math library that detects the abilities of the CPU (whether it has 3DNow, SSE, etc) and then modifies the behaviour of some class members to utilise an optimal implementation. I'm having trouble setting up the pointers correctly. I have the class definition

class O3DMVector {
public:
    float x, y, z, w;
    
    O3DMVector() {
        x = 0.0f; y = 0.0f; z = 0.0f; w = 1.0f;
    }
    inline float getLength() {
        return (*getLengthPtr)(*this);
    }
private:
    static float (*getLengthPtr)(O3DMVector &);
};

I also have some implementation details

float cGetLength(O3DMVector &v);

float (O3DMVector::*getLengthPtr)(O3DMVector &) = &cGetLength;

float cGetLength(O3DMVector &v) {
    return sqrt(v.x * v.x + v.y * v.y + v.z * v.z);
}

This gives me the error output

O3DMVector.cpp:5: error: cannot convert ‘float (*)(O3DMVector&)’ to ‘float (O3DMVector::*)(O3DMVector&)’ in initialization

I've tried modifying line 5 to read

float O3DMVector::(*getLengthPtr)(O3DMVector &) = &cGetLength;

This gives a different error

O3DMVector.cpp:5: error: expected unqualified-id before ‘(’ token

Anyone know what I have to do to get this working?