How do I apply a method to a template argument ?

See more:

C++

I know the question seems vague, so here's the code :

VectF Class:

template <typename Type, int Size = 0>
class VectF : public Vect<Type>{
private:
    //

protected:
    static const std::size_t _DIM = Size;
    Type _values[_DIM];

public:

    // getters
    virtual std::size_t size() const {return _DIM;};
   
};

And the ModPol Class:

template <typename Type, const ConPol<Type>& Div>
class ModPol : public Pol<Type>, public VectF<Type, Div.size()>{
private:
    //

protected:
    //

public:
    // constructors & destructor
    ModPol();      
    virtual ~ModPol();

};

So as you see the ModPol template class inherits from two other templates. In one of those I would like to use the result of the .size() method on Div as a parameter. Unfortunately I get this error:

Quote:

on-type template argument of type
'std::size_t' (aka 'unsigned long') is not an integral constant
expression
...: public Pol<type>, public VectF<type,>{ //

Would someone know how to get around that error ? (Do not hesitate to answer with simple words as I think of myself as a beginner).

Cheers !